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// mgo - MongoDB driver for Go
//
// Copyright (c) 2010-2012 - Gustavo Niemeyer <gustavo@niemeyer.net>
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
package mgo
import (
"crypto/md5"
"encoding/hex"
"errors"
"fmt"
"labix.org/v2/mgo/bson"
"math"
"net"
"net/url"
"reflect"
"sort"
"strconv"
"strings"
"sync"
"time"
)
type mode int
const (
Eventual mode = 0
Monotonic mode = 1
Strong mode = 2
)
// When changing the Session type, check if newSession and copySession
// need to be updated too.
type Session struct {
m sync.RWMutex
cluster_ *mongoCluster
slaveSocket *mongoSocket
masterSocket *mongoSocket
slaveOk bool
consistency mode
queryConfig query
safeOp *queryOp
syncTimeout time.Duration
sockTimeout time.Duration
defaultdb string
sourcedb string
dialCred *Credential
creds []Credential
}
type Database struct {
Session *Session
Name string
}
type Collection struct {
Database *Database
Name string // "collection"
FullName string // "db.collection"
}
type Query struct {
m sync.Mutex
session *Session
query // Enables default settings in session.
}
type query struct {
op queryOp
prefetch float64
limit int32
}
type getLastError struct {
CmdName int "getLastError"
W interface{} "w,omitempty"
WTimeout int "wtimeout,omitempty"
FSync bool "fsync,omitempty"
J bool "j,omitempty"
}
type Iter struct {
m sync.Mutex
gotReply sync.Cond
session *Session
server *mongoServer
docData queue
err error
op getMoreOp
prefetch float64
limit int32
docsToReceive int
docsBeforeMore int
timeout time.Duration
timedout bool
}
var ErrNotFound = errors.New("not found")
const defaultPrefetch = 0.25
// Dial establishes a new session to the cluster identified by the given seed
// server(s). The session will enable communication with all of the servers in
// the cluster, so the seed servers are used only to find out about the cluster
// topology.
//
// Dial will timeout after 10 seconds if a server isn't reached. The returned
// session will timeout operations after one minute by default if servers
// aren't available. To customize the timeout, see DialWithTimeout,
// SetSyncTimeout, and SetSocketTimeout.
//
// This method is generally called just once for a given cluster. Further
// sessions to the same cluster are then established using the New or Copy
// methods on the obtained session. This will make them share the underlying
// cluster, and manage the pool of connections appropriately.
//
// Once the session is not useful anymore, Close must be called to release the
// resources appropriately.
//
// The seed servers must be provided in the following format:
//
// [mongodb://][user:pass@]host1[:port1][,host2[:port2],...][/database][?options]
//
// For example, it may be as simple as:
//
// localhost
//
// Or more involved like:
//
// mongodb://myuser:mypass@localhost:40001,otherhost:40001/mydb
//
// If the port number is not provided for a server, it defaults to 27017.
//
// The username and password provided in the URL will be used to authenticate
// into the database named after the slash at the end of the host names, or
// into the "admin" database if none is provided. The authentication information
// will persist in sessions obtained through the New method as well.
//
// The following connection options are supported after the question mark:
//
// connect=direct
//
// Disables the automatic replica set server discovery logic, and
// forces the use of servers provided only (even if secondaries).
// Note that to talk to a secondary the consistency requirements
// must be relaxed to Monotonic or Eventual via SetMode.
//
//
// authSource=<db>
//
// Informs the database used to establish credentials and privileges
// with a MongoDB server. Defaults to the database name provided via
// the URL path, and "admin" if that's unset.
//
//
// authMechanism=<mechanism>
//
// Defines the protocol for credential negotiation. Defaults to "MONGODB-CR",
// which is the default username/password challenge-response mechanism.
//
//
// gssapiServiceName=<name>
//
// Defines the service name to use when authenticating with the GSSAPI
// mechanism. Defaults to "mongodb".
//
//
// Relevant documentation:
//
// http://docs.mongodb.org/manual/reference/connection-string/
//
func Dial(url string) (*Session, error) {
session, err := DialWithTimeout(url, 10*time.Second)
if err == nil {
session.SetSyncTimeout(1 * time.Minute)
session.SetSocketTimeout(1 * time.Minute)
}
return session, err
}
// DialWithTimeout works like Dial, but uses timeout as the amount of time to
// wait for a server to respond when first connecting and also on follow up
// operations in the session. If timeout is zero, the call may block
// forever waiting for a connection to be made.
//
// See SetSyncTimeout for customizing the timeout for the session.
func DialWithTimeout(url string, timeout time.Duration) (*Session, error) {
uinfo, err := parseURL(url)
if err != nil {
return nil, err
}
direct := false
mechanism := ""
service := ""
source := ""
for k, v := range uinfo.options {
switch k {
case "authSource":
source = v
case "authMechanism":
mechanism = v
case "gssapiServiceName":
service = v
case "connect":
if v == "direct" {
direct = true
break
}
if v == "replicaSet" {
break
}
fallthrough
default:
return nil, errors.New("unsupported connection URL option: " + k + "=" + v)
}
}
info := DialInfo{
Addrs: uinfo.addrs,
Direct: direct,
Timeout: timeout,
Database: uinfo.db,
Username: uinfo.user,
Password: uinfo.pass,
Mechanism: mechanism,
Service: service,
Source: source,
}
return DialWithInfo(&info)
}
// DialInfo holds options for establishing a session with a MongoDB cluster.
// To use a URL, see the Dial function.
type DialInfo struct {
// Addrs holds the addresses for the seed servers.
Addrs []string
// Direct informs whether to establish connections only with the
// specified seed servers, or to obtain information for the whole
// cluster and establish connections with further servers too.
Direct bool
// Timeout is the amount of time to wait for a server to respond when
// first connecting and on follow up operations in the session. If
// timeout is zero, the call may block forever waiting for a connection
// to be established.
Timeout time.Duration
// FailFast will cause connection and query attempts to fail faster when
// the server is unavailable, instead of retrying until the configured
// timeout period. Note that an unavailable server may silently drop
// packets instead of rejecting them, in which case it's impossible to
// distinguish it from a slow server, so the timeout stays relevant.
FailFast bool
// Database is the default database name used when the Session.DB method
// is called with an empty name, and is also used during the intial
// authenticatoin if Source is unset.
Database string
// Source is the database used to establish credentials and privileges
// with a MongoDB server. Defaults to the value of Database, if that is
// set, or "admin" otherwise.
Source string
// Service defines the service name to use when authenticating with the GSSAPI
// mechanism. Defaults to "mongodb".
Service string
// Mechanism defines the protocol for credential negotiation.
// Defaults to "MONGODB-CR".
Mechanism string
// Username and Password inform the credentials for the initial authentication
// done on the database defined by the Source field. See Session.Login.
Username string
Password string
// DialServer optionally specifies the dial function for establishing
// connections with the MongoDB servers.
DialServer func(addr *ServerAddr) (net.Conn, error)
// WARNING: This field is obsolete. See DialServer above.
Dial func(addr net.Addr) (net.Conn, error)
}
// ServerAddr represents the address for establishing a connection to an
// individual MongoDB server.
type ServerAddr struct {
str string
tcp *net.TCPAddr
}
// String returns the address that was provided for the server before resolution.
func (addr *ServerAddr) String() string {
return addr.str
}
// TCPAddr returns the resolved TCP address for the server.
func (addr *ServerAddr) TCPAddr() *net.TCPAddr {
return addr.tcp
}
// DialWithInfo establishes a new session to the cluster identified by info.
func DialWithInfo(info *DialInfo) (*Session, error) {
addrs := make([]string, len(info.Addrs))
for i, addr := range info.Addrs {
p := strings.LastIndexAny(addr, "]:")
if p == -1 || addr[p] != ':' {
// XXX This is untested. The test suite doesn't use the standard port.
addr += ":27017"
}
addrs[i] = addr
}
cluster := newCluster(addrs, info.Direct, info.FailFast, dialer{info.Dial, info.DialServer})
session := newSession(Eventual, cluster, info.Timeout)
session.defaultdb = info.Database
if session.defaultdb == "" {
session.defaultdb = "test"
}
session.sourcedb = info.Source
if session.sourcedb == "" {
session.sourcedb = info.Database
if session.sourcedb == "" {
session.sourcedb = "admin"
}
}
if info.Username != "" {
source := session.sourcedb
if info.Source == "" && (info.Mechanism == "GSSAPI" || info.Mechanism == "PLAIN") {
source = "$external"
}
session.dialCred = &Credential{
Username: info.Username,
Password: info.Password,
Mechanism: info.Mechanism,
Service: info.Service,
Source: source,
}
session.creds = []Credential{*session.dialCred}
}
cluster.Release()
// People get confused when we return a session that is not actually
// established to any servers yet (e.g. what if url was wrong). So,
// ping the server to ensure there's someone there, and abort if it
// fails.
if err := session.Ping(); err != nil {
session.Close()
return nil, err
}
session.SetMode(Strong, true)
return session, nil
}
func isOptSep(c rune) bool {
return c == ';' || c == '&'
}
type urlInfo struct {
addrs []string
user string
pass string
db string
options map[string]string
}
func parseURL(s string) (*urlInfo, error) {
if strings.HasPrefix(s, "mongodb://") {
s = s[10:]
}
info := &urlInfo{options: make(map[string]string)}
if c := strings.Index(s, "?"); c != -1 {
for _, pair := range strings.FieldsFunc(s[c+1:], isOptSep) {
l := strings.SplitN(pair, "=", 2)
if len(l) != 2 || l[0] == "" || l[1] == "" {
return nil, errors.New("connection option must be key=value: " + pair)
}
info.options[l[0]] = l[1]
}
s = s[:c]
}
if c := strings.Index(s, "@"); c != -1 {
pair := strings.SplitN(s[:c], ":", 2)
if len(pair) > 2 || pair[0] == "" {
return nil, errors.New("credentials must be provided as user:pass@host")
}
var err error
info.user, err = url.QueryUnescape(pair[0])
if err != nil {
return nil, fmt.Errorf("cannot unescape username in URL: %q", pair[0])
}
if len(pair) > 1 {
info.pass, err = url.QueryUnescape(pair[1])
if err != nil {
return nil, fmt.Errorf("cannot unescape password in URL")
}
}
s = s[c+1:]
}
if c := strings.Index(s, "/"); c != -1 {
info.db = s[c+1:]
s = s[:c]
}
info.addrs = strings.Split(s, ",")
return info, nil
}
func newSession(consistency mode, cluster *mongoCluster, timeout time.Duration) (session *Session) {
cluster.Acquire()
session = &Session{cluster_: cluster, syncTimeout: timeout, sockTimeout: timeout}
debugf("New session %p on cluster %p", session, cluster)
session.SetMode(consistency, true)
session.SetSafe(&Safe{})
session.queryConfig.prefetch = defaultPrefetch
return session
}
func copySession(session *Session, keepCreds bool) (s *Session) {
cluster := session.cluster()
cluster.Acquire()
if session.masterSocket != nil {
session.masterSocket.Acquire()
}
if session.slaveSocket != nil {
session.slaveSocket.Acquire()
}
var creds []Credential
if keepCreds {
creds = make([]Credential, len(session.creds))
copy(creds, session.creds)
} else if session.dialCred != nil {
creds = []Credential{*session.dialCred}
}
scopy := *session
scopy.m = sync.RWMutex{}
scopy.creds = creds
s = &scopy
debugf("New session %p on cluster %p (copy from %p)", s, cluster, session)
return s
}
// LiveServers returns a list of server addresses which are
// currently known to be alive.
func (s *Session) LiveServers() (addrs []string) {
s.m.RLock()
addrs = s.cluster().LiveServers()
s.m.RUnlock()
return addrs
}
// DB returns a value representing the named database. If name
// is empty, the database name provided in the dialed URL is
// used instead. If that is also empty, "test" is used as a
// fallback in a way equivalent to the mongo shell.
//
// Creating this value is a very lightweight operation, and
// involves no network communication.
func (s *Session) DB(name string) *Database {
if name == "" {
name = s.defaultdb
}
return &Database{s, name}
}
// C returns a value representing the named collection.
//
// Creating this value is a very lightweight operation, and
// involves no network communication.
func (db *Database) C(name string) *Collection {
return &Collection{db, name, db.Name + "." + name}
}
// With returns a copy of db that uses session s.
func (db *Database) With(s *Session) *Database {
newdb := *db
newdb.Session = s
return &newdb
}
// With returns a copy of c that uses session s.
func (c *Collection) With(s *Session) *Collection {
newdb := *c.Database
newdb.Session = s
newc := *c
newc.Database = &newdb
return &newc
}
// GridFS returns a GridFS value representing collections in db that
// follow the standard GridFS specification.
// The provided prefix (sometimes known as root) will determine which
// collections to use, and is usually set to "fs" when there is a
// single GridFS in the database.
//
// See the GridFS Create, Open, and OpenId methods for more details.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/GridFS
// http://www.mongodb.org/display/DOCS/GridFS+Tools
// http://www.mongodb.org/display/DOCS/GridFS+Specification
//
func (db *Database) GridFS(prefix string) *GridFS {
return newGridFS(db, prefix)
}
// Run issues the provided command on the db database and unmarshals
// its result in the respective argument. The cmd argument may be either
// a string with the command name itself, in which case an empty document of
// the form bson.M{cmd: 1} will be used, or it may be a full command document.
//
// Note that MongoDB considers the first marshalled key as the command
// name, so when providing a command with options, it's important to
// use an ordering-preserving document, such as a struct value or an
// instance of bson.D. For instance:
//
// db.Run(bson.D{{"create", "mycollection"}, {"size", 1024}})
//
// For privilleged commands typically run on the "admin" database, see
// the Run method in the Session type.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Commands
// http://www.mongodb.org/display/DOCS/List+of+Database+CommandSkips
//
func (db *Database) Run(cmd interface{}, result interface{}) error {
if name, ok := cmd.(string); ok {
cmd = bson.D{{name, 1}}
}
return db.C("$cmd").Find(cmd).One(result)
}
// Credential holds details to authenticate with a MongoDB server.
type Credential struct {
// Username and Password hold the basic details for authentication.
// Password is optional with some authentication mechanisms.
Username string
Password string
// Source is the database used to establish credentials and privileges
// with a MongoDB server. Defaults to the default database provided
// during dial, or "admin" if that was unset.
Source string
// Service defines the service name to use when authenticating with the GSSAPI
// mechanism. Defaults to "mongodb".
Service string
// Mechanism defines the protocol for credential negotiation.
// Defaults to "MONGODB-CR".
Mechanism string
}
// Login authenticates with MongoDB using the provided credential. The
// authentication is valid for the whole session and will stay valid until
// Logout is explicitly called for the same database, or the session is
// closed.
func (db *Database) Login(user, pass string) error {
return db.Session.Login(&Credential{Username: user, Password: pass, Source: db.Name})
}
// Login authenticates with MongoDB using the provided credential. The
// authentication is valid for the whole session and will stay valid until
// Logout is explicitly called for the same database, or the session is
// closed.
func (s *Session) Login(cred *Credential) error {
socket, err := s.acquireSocket(true)
if err != nil {
return err
}
defer socket.Release()
credCopy := *cred
if cred.Source == "" {
if cred.Mechanism == "GSSAPI" {
credCopy.Source = "$external"
} else {
credCopy.Source = s.sourcedb
}
}
err = socket.Login(credCopy)
if err != nil {
return err
}
s.m.Lock()
s.creds = append(s.creds, credCopy)
s.m.Unlock()
return nil
}
func (s *Session) socketLogin(socket *mongoSocket) error {
for _, cred := range s.creds {
if err := socket.Login(cred); err != nil {
return err
}
}
return nil
}
// Logout removes any established authentication credentials for the database.
func (db *Database) Logout() {
session := db.Session
dbname := db.Name
session.m.Lock()
found := false
for i, cred := range session.creds {
if cred.Source == dbname {
copy(session.creds[i:], session.creds[i+1:])
session.creds = session.creds[:len(session.creds)-1]
found = true
break
}
}
if found {
if session.masterSocket != nil {
session.masterSocket.Logout(dbname)
}
if session.slaveSocket != nil {
session.slaveSocket.Logout(dbname)
}
}
session.m.Unlock()
}
// LogoutAll removes all established authentication credentials for the session.
func (s *Session) LogoutAll() {
s.m.Lock()
for _, cred := range s.creds {
if s.masterSocket != nil {
s.masterSocket.Logout(cred.Source)
}
if s.slaveSocket != nil {
s.slaveSocket.Logout(cred.Source)
}
}
s.creds = s.creds[0:0]
s.m.Unlock()
}
// User represents a MongoDB user.
//
// Relevant documentation:
//
// http://docs.mongodb.org/manual/reference/privilege-documents/
// http://docs.mongodb.org/manual/reference/user-privileges/
//
type User struct {
// Username is how the user identifies itself to the system.
Username string `bson:"user"`
// Password is the plaintext password for the user. If set,
// the UpsertUser method will hash it into PasswordHash and
// unset it before the user is added to the database.
Password string `bson:",omitempty"`
// PasswordHash is the MD5 hash of Username+":mongo:"+Password.
PasswordHash string `bson:"pwd,omitempty"`
// CustomData holds arbitrary data admins decide to associate
// with this user, such as the full name or employee id.
CustomData interface{} `bson:"customData,omitempty"`
// Roles indicates the set of roles the user will be provided.
// See the Role constants.
Roles []Role `bson:"roles"`
// OtherDBRoles allows assigning roles in other databases from
// user documents inserted in the admin database. This field
// only works in the admin database.
OtherDBRoles map[string][]Role `bson:"otherDBRoles,omitempty"`
// UserSource indicates where to look for this user's credentials.
// It may be set to a database name, or to "$external" for
// consulting an external resource such as Kerberos. UserSource
// must not be set if Password or PasswordHash are present.
//
// WARNING: This setting was only ever supported in MongoDB 2.4,
// and is now obsolete.
UserSource string `bson:"userSource,omitempty"`
}
type Role string
const (
// Relevant documentation:
//
// http://docs.mongodb.org/manual/reference/user-privileges/
//
RoleRoot Role = "root"
RoleRead Role = "read"
RoleReadAny Role = "readAnyDatabase"
RoleReadWrite Role = "readWrite"
RoleReadWriteAny Role = "readWriteAnyDatabase"
RoleDBAdmin Role = "dbAdmin"
RoleDBAdminAny Role = "dbAdminAnyDatabase"
RoleUserAdmin Role = "userAdmin"
RoleUserAdminAny Role = "userAdminAnyDatabase"
RoleClusterAdmin Role = "clusterAdmin"
)
// UpsertUser updates the authentication credentials and the roles for
// a MongoDB user within the db database. If the named user doesn't exist
// it will be created.
//
// This method should only be used from MongoDB 2.4 and on. For older
// MongoDB releases, use the obsolete AddUser method instead.
//
// Relevant documentation:
//
// http://docs.mongodb.org/manual/reference/user-privileges/
// http://docs.mongodb.org/manual/reference/privilege-documents/
//
func (db *Database) UpsertUser(user *User) error {
if user.Username == "" {
return fmt.Errorf("user has no Username")
}
if (user.Password != "" || user.PasswordHash != "") && user.UserSource != "" {
return fmt.Errorf("user has both Password/PasswordHash and UserSource set")
}
if len(user.OtherDBRoles) > 0 && db.Name != "admin" {
return fmt.Errorf("user with OtherDBRoles is only supported in admin database")
}
// Attempt to run this using 2.6+ commands.
rundb := db
if user.UserSource != "" {
// Compatibility logic for the userSource field of MongoDB <= 2.4.X
rundb = db.Session.DB(user.UserSource)
}
err := rundb.runUserCmd("updateUser", user)
if e, ok := err.(*QueryError); ok && e.Code == 11 {
return rundb.runUserCmd("createUser", user)
}
if !isNoCmd(err) {
return err
}
// Command does not exist. Fallback to pre-2.6 behavior.
var set, unset bson.D
if user.Password != "" {
psum := md5.New()
psum.Write([]byte(user.Username + ":mongo:" + user.Password))
set = append(set, bson.DocElem{"pwd", hex.EncodeToString(psum.Sum(nil))})
unset = append(unset, bson.DocElem{"userSource", 1})
} else if user.PasswordHash != "" {
set = append(set, bson.DocElem{"pwd", user.PasswordHash})
unset = append(unset, bson.DocElem{"userSource", 1})
}
if user.UserSource != "" {
set = append(set, bson.DocElem{"userSource", user.UserSource})
unset = append(unset, bson.DocElem{"pwd", 1})
}
if user.Roles != nil || user.OtherDBRoles != nil {
set = append(set, bson.DocElem{"roles", user.Roles})
if len(user.OtherDBRoles) > 0 {
set = append(set, bson.DocElem{"otherDBRoles", user.OtherDBRoles})
} else {
unset = append(unset, bson.DocElem{"otherDBRoles", 1})
}
}
users := db.C("system.users")
err = users.Update(bson.D{{"user", user.Username}}, bson.D{{"$unset", unset}, {"$set", set}})
if err == ErrNotFound {
set = append(set, bson.DocElem{"user", user.Username})
if user.Roles == nil && user.OtherDBRoles == nil {
// Roles must be sent, as it's the way MongoDB distinguishes
// old-style documents from new-style documents in pre-2.6.
set = append(set, bson.DocElem{"roles", user.Roles})
}
err = users.Insert(set)
}
return err
}
func isNoCmd(err error) bool {
e, ok := err.(*QueryError)
return ok && strings.HasPrefix(e.Message, "no such cmd:")
}
func (db *Database) runUserCmd(cmdName string, user *User) error {
//if user.UserSource != "" && (user.UserSource != "$external" || db.Name != "$external") {
// return fmt.Errorf("MongoDB 2.6+ does not support the UserSource setting")
//}
cmd := make(bson.D, 0, 16)
cmd = append(cmd, bson.DocElem{cmdName, user.Username})
if user.Password != "" {
cmd = append(cmd, bson.DocElem{"pwd", user.Password})
}
var roles []interface{}
for _, role := range user.Roles {
roles = append(roles, role)
}
for db, dbroles := range user.OtherDBRoles {
for _, role := range dbroles {
roles = append(roles, bson.D{{"role", role}, {"db", db}})
}
}
if roles != nil || user.Roles != nil || cmdName == "createUser" {
cmd = append(cmd, bson.DocElem{"roles", roles})
}
return db.Run(cmd, nil)
}
// AddUser creates or updates the authentication credentials of user within
// the db database.
//
// WARNING: This method is obsolete and should only be used with MongoDB 2.2
// or earlier. For MongoDB 2.4 and on, use UpsertUser instead.
func (db *Database) AddUser(username, password string, readOnly bool) error {
// Try to emulate the old behavior on 2.6+
user := &User{Username: username, Password: password}
if db.Name == "admin" {
if readOnly {
user.Roles = []Role{RoleReadAny}
} else {
user.Roles = []Role{RoleReadWriteAny}
}
} else {
if readOnly {
user.Roles = []Role{RoleRead}
} else {
user.Roles = []Role{RoleReadWrite}
}
}
err := db.runUserCmd("updateUser", user)
if e, ok := err.(*QueryError); ok && e.Code == 11 {
return db.runUserCmd("createUser", user)
}
if !isNoCmd(err) {
return err
}
// Command doesn't exist. Fallback to pre-2.6 behavior.
psum := md5.New()
psum.Write([]byte(username + ":mongo:" + password))
digest := hex.EncodeToString(psum.Sum(nil))
c := db.C("system.users")
_, err = c.Upsert(bson.M{"user": username}, bson.M{"$set": bson.M{"user": username, "pwd": digest, "readOnly": readOnly}})
return err
}
// RemoveUser removes the authentication credentials of user from the database.
func (db *Database) RemoveUser(user string) error {
err := db.Run(bson.D{{"dropUser", user}}, nil)
if isNoCmd(err) {
users := db.C("system.users")
return users.Remove(bson.M{"user": user})
}
return err
}
type indexSpec struct {
Name, NS string
Key bson.D
Unique bool ",omitempty"
DropDups bool "dropDups,omitempty"
Background bool ",omitempty"
Sparse bool ",omitempty"
Bits, Min, Max int ",omitempty"
ExpireAfter int "expireAfterSeconds,omitempty"
}
type Index struct {
Key []string // Index key fields; prefix name with dash (-) for descending order
Unique bool // Prevent two documents from having the same index key
DropDups bool // Drop documents with the same index key as a previously indexed one
Background bool // Build index in background and return immediately
Sparse bool // Only index documents containing the Key fields
ExpireAfter time.Duration // Periodically delete docs with indexed time.Time older than that.
Name string // Index name, computed by EnsureIndex
Bits, Min, Max int // Properties for spatial indexes
}
func parseIndexKey(key []string) (name string, realKey bson.D, err error) {
var order interface{}
for _, field := range key {
raw := field
if name != "" {
name += "_"
}
var kind string
if field != "" {
if field[0] == '$' {
if c := strings.Index(field, ":"); c > 1 && c < len(field)-1 {
kind = field[1:c]
field = field[c+1:]
name += field + "_" + kind
}
}
switch field[0] {
case '$':
// Logic above failed. Reset and error.
field = ""
case '@':
order = "2d"
field = field[1:]
// The shell used to render this field as key_ instead of key_2d,
// and mgo followed suit. This has been fixed in recent server
// releases, and mgo followed as well.
name += field + "_2d"
case '-':
order = -1
field = field[1:]
name += field + "_-1"
case '+':
field = field[1:]
fallthrough
default:
if kind == "" {
order = 1
name += field + "_1"
} else {
order = kind
}
}
}
if field == "" || kind != "" && order != kind {
return "", nil, fmt.Errorf(`invalid index key: want "[$<kind>:][-]<field name>", got %q`, raw)
}
realKey = append(realKey, bson.DocElem{field, order})
}
if name == "" {
return "", nil, errors.New("invalid index key: no fields provided")
}
return
}
// EnsureIndexKey ensures an index with the given key exists, creating it
// if necessary.
//
// This example:
//
// err := collection.EnsureIndexKey("a", "b")
//
// Is equivalent to:
//
// err := collection.EnsureIndex(mgo.Index{Key: []string{"a", "b"}})
//
// See the EnsureIndex method for more details.
func (c *Collection) EnsureIndexKey(key ...string) error {
return c.EnsureIndex(Index{Key: key})
}
// EnsureIndex ensures an index with the given key exists, creating it with
// the provided parameters if necessary.
//
// Once EnsureIndex returns successfully, following requests for the same index
// will not contact the server unless Collection.DropIndex is used to drop the
// same index, or Session.ResetIndexCache is called.
//
// For example:
//
// index := Index{
// Key: []string{"lastname", "firstname"},
// Unique: true,
// DropDups: true,
// Background: true, // See notes.
// Sparse: true,
// }
// err := collection.EnsureIndex(index)
//
// The Key value determines which fields compose the index. The index ordering
// will be ascending by default. To obtain an index with a descending order,
// the field name should be prefixed by a dash (e.g. []string{"-time"}).
//
// If Unique is true, the index must necessarily contain only a single
// document per Key. With DropDups set to true, documents with the same key
// as a previously indexed one will be dropped rather than an error returned.
//
// If Background is true, other connections will be allowed to proceed using
// the collection without the index while it's being built. Note that the
// session executing EnsureIndex will be blocked for as long as it takes for
// the index to be built.
//
// If Sparse is true, only documents containing the provided Key fields will be
// included in the index. When using a sparse index for sorting, only indexed
// documents will be returned.
//
// If ExpireAfter is non-zero, the server will periodically scan the collection
// and remove documents containing an indexed time.Time field with a value
// older than ExpireAfter. See the documentation for details:
//
// http://docs.mongodb.org/manual/tutorial/expire-data
//
// Other kinds of indexes are also supported through that API. Here is an example:
//
// index := Index{
// Key: []string{"$2d:loc"},
// Bits: 26,
// }
// err := collection.EnsureIndex(index)
//
// The example above requests the creation of a "2d" index for the "loc" field.
//
// The 2D index bounds may be changed using the Min and Max attributes of the
// Index value. The default bound setting of (-180, 180) is suitable for
// latitude/longitude pairs.
//
// The Bits parameter sets the precision of the 2D geohash values. If not
// provided, 26 bits are used, which is roughly equivalent to 1 foot of
// precision for the default (-180, 180) index bounds.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Indexes
// http://www.mongodb.org/display/DOCS/Indexing+Advice+and+FAQ
// http://www.mongodb.org/display/DOCS/Indexing+as+a+Background+Operation
// http://www.mongodb.org/display/DOCS/Geospatial+Indexing
// http://www.mongodb.org/display/DOCS/Multikeys
//
func (c *Collection) EnsureIndex(index Index) error {
name, realKey, err := parseIndexKey(index.Key)
if err != nil {
return err
}
session := c.Database.Session
cacheKey := c.FullName + "\x00" + name
if session.cluster().HasCachedIndex(cacheKey) {
return nil
}
spec := indexSpec{
Name: name,
NS: c.FullName,
Key: realKey,
Unique: index.Unique,
DropDups: index.DropDups,
Background: index.Background,
Sparse: index.Sparse,
Bits: index.Bits,
Min: index.Min,
Max: index.Max,
ExpireAfter: int(index.ExpireAfter / time.Second),
}
session = session.Clone()
defer session.Close()
session.SetMode(Strong, false)
session.EnsureSafe(&Safe{})
db := c.Database.With(session)
err = db.C("system.indexes").Insert(&spec)
if err == nil {
session.cluster().CacheIndex(cacheKey, true)
}
session.Close()
return err
}
// DropIndex removes the index with key from the collection.
//
// The key value determines which fields compose the index. The index ordering
// will be ascending by default. To obtain an index with a descending order,
// the field name should be prefixed by a dash (e.g. []string{"-time"}).
//
// For example:
//
// err := collection.DropIndex("lastname", "firstname")
//
// See the EnsureIndex method for more details on indexes.
func (c *Collection) DropIndex(key ...string) error {
name, _, err := parseIndexKey(key)
if err != nil {
return err
}
session := c.Database.Session
cacheKey := c.FullName + "\x00" + name
session.cluster().CacheIndex(cacheKey, false)
session = session.Clone()
defer session.Close()
session.SetMode(Strong, false)
db := c.Database.With(session)
result := struct {
ErrMsg string
Ok bool
}{}
err = db.Run(bson.D{{"dropIndexes", c.Name}, {"index", name}}, &result)
if err != nil {
return err
}
if !result.Ok {
return errors.New(result.ErrMsg)
}
return nil
}
// Indexes returns a list of all indexes for the collection.
//
// For example, this snippet would drop all available indexes:
//
// indexes, err := collection.Indexes()
// if err != nil {
// return err
// }
// for _, index := range indexes {
// err = collection.DropIndex(index.Key...)
// if err != nil {
// return err
// }
// }
//
// See the EnsureIndex method for more details on indexes.
func (c *Collection) Indexes() (indexes []Index, err error) {
query := c.Database.C("system.indexes").Find(bson.M{"ns": c.FullName})
iter := query.Sort("name").Iter()
for {
var spec indexSpec
if !iter.Next(&spec) {
break
}
index := Index{
Name: spec.Name,
Key: simpleIndexKey(spec.Key),
Unique: spec.Unique,
DropDups: spec.DropDups,
Background: spec.Background,
Sparse: spec.Sparse,
ExpireAfter: time.Duration(spec.ExpireAfter) * time.Second,
}
indexes = append(indexes, index)
}
err = iter.Close()
return
}
func simpleIndexKey(realKey bson.D) (key []string) {
for i := range realKey {
field := realKey[i].Name
vi, ok := realKey[i].Value.(int)
if !ok {
vf, _ := realKey[i].Value.(float64)
vi = int(vf)
}
if vi == 1 {
key = append(key, field)
continue
}
if vi == -1 {
key = append(key, "-"+field)
continue
}
if vs, ok := realKey[i].Value.(string); ok {
key = append(key, "$"+vs+":"+field)
continue
}
panic("Got unknown index key type for field " + field)
}
return
}
// ResetIndexCache() clears the cache of previously ensured indexes.
// Following requests to EnsureIndex will contact the server.
func (s *Session) ResetIndexCache() {
s.cluster().ResetIndexCache()
}
// New creates a new session with the same parameters as the original
// session, including consistency, batch size, prefetching, safety mode,
// etc. The returned session will use sockets from the pool, so there's
// a chance that writes just performed in another session may not yet
// be visible.
//
// Login information from the original session will not be copied over
// into the new session unless it was provided through the initial URL
// for the Dial function.
//
// See the Copy and Clone methods.
//
func (s *Session) New() *Session {
s.m.Lock()
scopy := copySession(s, false)
s.m.Unlock()
scopy.Refresh()
return scopy
}
// Copy works just like New, but preserves the exact authentication
// information from the original session.
func (s *Session) Copy() *Session {
s.m.Lock()
scopy := copySession(s, true)
s.m.Unlock()
scopy.Refresh()
return scopy
}
// Clone works just like Copy, but also reuses the same socket as the original
// session, in case it had already reserved one due to its consistency
// guarantees. This behavior ensures that writes performed in the old session
// are necessarily observed when using the new session, as long as it was a
// strong or monotonic session. That said, it also means that long operations
// may cause other goroutines using the original session to wait.
func (s *Session) Clone() *Session {
s.m.Lock()
scopy := copySession(s, true)
s.m.Unlock()
return scopy
}
// Close terminates the session. It's a runtime error to use a session
// after it has been closed.
func (s *Session) Close() {
s.m.Lock()
if s.cluster_ != nil {
debugf("Closing session %p", s)
s.unsetSocket()
s.cluster_.Release()
s.cluster_ = nil
}
s.m.Unlock()
}
func (s *Session) cluster() *mongoCluster {
if s.cluster_ == nil {
panic("Session already closed")
}
return s.cluster_
}
// Refresh puts back any reserved sockets in use and restarts the consistency
// guarantees according to the current consistency setting for the session.
func (s *Session) Refresh() {
s.m.Lock()
s.slaveOk = s.consistency != Strong
s.unsetSocket()
s.m.Unlock()
}
// SetMode changes the consistency mode for the session.
//
// In the Strong consistency mode reads and writes will always be made to
// the primary server using a unique connection so that reads and writes are
// fully consistent, ordered, and observing the most up-to-date data.
// This offers the least benefits in terms of distributing load, but the
// most guarantees. See also Monotonic and Eventual.
//
// In the Monotonic consistency mode reads may not be entirely up-to-date,
// but they will always see the history of changes moving forward, the data
// read will be consistent across sequential queries in the same session,
// and modifications made within the session will be observed in following
// queries (read-your-writes).
//
// In practice, the Monotonic mode is obtained by performing initial reads
// on a unique connection to an arbitrary secondary, if one is available,
// and once the first write happens, the session connection is switched over
// to the primary server. This manages to distribute some of the reading
// load with secondaries, while maintaining some useful guarantees.
//
// In the Eventual consistency mode reads will be made to any secondary in the
// cluster, if one is available, and sequential reads will not necessarily
// be made with the same connection. This means that data may be observed
// out of order. Writes will of course be issued to the primary, but
// independent writes in the same Eventual session may also be made with
// independent connections, so there are also no guarantees in terms of
// write ordering (no read-your-writes guarantees either).
//
// The Eventual mode is the fastest and most resource-friendly, but is
// also the one offering the least guarantees about ordering of the data
// read and written.
//
// If refresh is true, in addition to ensuring the session is in the given
// consistency mode, the consistency guarantees will also be reset (e.g.
// a Monotonic session will be allowed to read from secondaries again).
// This is equivalent to calling the Refresh function.
//
// Shifting between Monotonic and Strong modes will keep a previously
// reserved connection for the session unless refresh is true or the
// connection is unsuitable (to a secondary server in a Strong session).
func (s *Session) SetMode(consistency mode, refresh bool) {
s.m.Lock()
debugf("Session %p: setting mode %d with refresh=%v (master=%p, slave=%p)", s, consistency, refresh, s.masterSocket, s.slaveSocket)
s.consistency = consistency
if refresh {
s.slaveOk = s.consistency != Strong
s.unsetSocket()
} else if s.consistency == Strong {
s.slaveOk = false
} else if s.masterSocket == nil {
s.slaveOk = true
}
s.m.Unlock()
}
// Mode returns the current consistency mode for the session.
func (s *Session) Mode() mode {
s.m.RLock()
mode := s.consistency
s.m.RUnlock()
return mode
}
// SetSyncTimeout sets the amount of time an operation with this session
// will wait before returning an error in case a connection to a usable
// server can't be established. Set it to zero to wait forever. The
// default value is 7 seconds.
func (s *Session) SetSyncTimeout(d time.Duration) {
s.m.Lock()
s.syncTimeout = d
s.m.Unlock()
}
// SetSocketTimeout sets the amount of time to wait for a non-responding
// socket to the database before it is forcefully closed.
func (s *Session) SetSocketTimeout(d time.Duration) {
s.m.Lock()
s.sockTimeout = d
if s.masterSocket != nil {
s.masterSocket.SetTimeout(d)
}
if s.slaveSocket != nil {
s.slaveSocket.SetTimeout(d)
}
s.m.Unlock()
}
// SetCursorTimeout changes the standard timeout period that the server
// enforces on created cursors. The only supported value right now is
// 0, which disables the timeout. The standard server timeout is 10 minutes.
func (s *Session) SetCursorTimeout(d time.Duration) {
s.m.Lock()
if d == 0 {
s.queryConfig.op.flags |= flagNoCursorTimeout
} else {
panic("SetCursorTimeout: only 0 (disable timeout) supported for now")
}
s.m.Unlock()
}
// SetBatch sets the default batch size used when fetching documents from the
// database. It's possible to change this setting on a per-query basis as
// well, using the Query.Batch method.
//
// The default batch size is defined by the database itself. As of this
// writing, MongoDB will use an initial size of min(100 docs, 4MB) on the
// first batch, and 4MB on remaining ones.
func (s *Session) SetBatch(n int) {
if n == 1 {
// Server interprets 1 as -1 and closes the cursor (!?)
n = 2
}
s.m.Lock()
s.queryConfig.op.limit = int32(n)
s.m.Unlock()
}
// SetPrefetch sets the default point at which the next batch of results will be
// requested. When there are p*batch_size remaining documents cached in an
// Iter, the next batch will be requested in background. For instance, when
// using this:
//
// session.SetBatch(200)
// session.SetPrefetch(0.25)
//
// and there are only 50 documents cached in the Iter to be processed, the
// next batch of 200 will be requested. It's possible to change this setting on
// a per-query basis as well, using the Prefetch method of Query.
//
// The default prefetch value is 0.25.
func (s *Session) SetPrefetch(p float64) {
s.m.Lock()
s.queryConfig.prefetch = p
s.m.Unlock()
}
// See SetSafe for details on the Safe type.
type Safe struct {
W int // Min # of servers to ack before success
WMode string // Write mode for MongoDB 2.0+ (e.g. "majority")
WTimeout int // Milliseconds to wait for W before timing out
FSync bool // Should servers sync to disk before returning success
J bool // Wait for next group commit if journaling; no effect otherwise
}
// Safe returns the current safety mode for the session.
func (s *Session) Safe() (safe *Safe) {
s.m.Lock()
defer s.m.Unlock()
if s.safeOp != nil {
cmd := s.safeOp.query.(*getLastError)
safe = &Safe{WTimeout: cmd.WTimeout, FSync: cmd.FSync, J: cmd.J}
switch w := cmd.W.(type) {
case string:
safe.WMode = w
case int:
safe.W = w
}
}
return
}
// SetSafe changes the session safety mode.
//
// If the safe parameter is nil, the session is put in unsafe mode, and writes
// become fire-and-forget, without error checking. The unsafe mode is faster
// since operations won't hold on waiting for a confirmation.
//
// If the safe parameter is not nil, any changing query (insert, update, ...)
// will be followed by a getLastError command with the specified parameters,
// to ensure the request was correctly processed.
//
// The safe.W parameter determines how many servers should confirm a write
// before the operation is considered successful. If set to 0 or 1, the
// command will return as soon as the primary is done with the request.
// If safe.WTimeout is greater than zero, it determines how many milliseconds
// to wait for the safe.W servers to respond before returning an error.
//
// Starting with MongoDB 2.0.0 the safe.WMode parameter can be used instead
// of W to request for richer semantics. If set to "majority" the server will
// wait for a majority of members from the replica set to respond before
// returning. Custom modes may also be defined within the server to create
// very detailed placement schemas. See the data awareness documentation in
// the links below for more details (note that MongoDB internally reuses the
// "w" field name for WMode).
//
// If safe.FSync is true and journaling is disabled, the servers will be
// forced to sync all files to disk immediately before returning. If the
// same option is true but journaling is enabled, the server will instead
// await for the next group commit before returning.
//
// Since MongoDB 2.0.0, the safe.J option can also be used instead of FSync
// to force the server to wait for a group commit in case journaling is
// enabled. The option has no effect if the server has journaling disabled.
//
// For example, the following statement will make the session check for
// errors, without imposing further constraints:
//
// session.SetSafe(&mgo.Safe{})
//
// The following statement will force the server to wait for a majority of
// members of a replica set to return (MongoDB 2.0+ only):
//
// session.SetSafe(&mgo.Safe{WMode: "majority"})
//
// The following statement, on the other hand, ensures that at least two
// servers have flushed the change to disk before confirming the success
// of operations:
//
// session.EnsureSafe(&mgo.Safe{W: 2, FSync: true})
//
// The following statement, on the other hand, disables the verification
// of errors entirely:
//
// session.SetSafe(nil)
//
// See also the EnsureSafe method.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/getLastError+Command
// http://www.mongodb.org/display/DOCS/Verifying+Propagation+of+Writes+with+getLastError
// http://www.mongodb.org/display/DOCS/Data+Center+Awareness
//
func (s *Session) SetSafe(safe *Safe) {
s.m.Lock()
s.safeOp = nil
s.ensureSafe(safe)
s.m.Unlock()
}
// EnsureSafe compares the provided safety parameters with the ones
// currently in use by the session and picks the most conservative
// choice for each setting.
//
// That is:
//
// - safe.WMode is always used if set.
// - safe.W is used if larger than the current W and WMode is empty.
// - safe.FSync is always used if true.
// - safe.J is used if FSync is false.
// - safe.WTimeout is used if set and smaller than the current WTimeout.
//
// For example, the following statement will ensure the session is
// at least checking for errors, without enforcing further constraints.
// If a more conservative SetSafe or EnsureSafe call was previously done,
// the following call will be ignored.
//
// session.EnsureSafe(&mgo.Safe{})
//
// See also the SetSafe method for details on what each option means.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/getLastError+Command
// http://www.mongodb.org/display/DOCS/Verifying+Propagation+of+Writes+with+getLastError
// http://www.mongodb.org/display/DOCS/Data+Center+Awareness
//
func (s *Session) EnsureSafe(safe *Safe) {
s.m.Lock()
s.ensureSafe(safe)
s.m.Unlock()
}
func (s *Session) ensureSafe(safe *Safe) {
if safe == nil {
return
}
var w interface{}
if safe.WMode != "" {
w = safe.WMode
} else if safe.W > 0 {
w = safe.W
}
var cmd getLastError
if s.safeOp == nil {
cmd = getLastError{1, w, safe.WTimeout, safe.FSync, safe.J}
} else {
// Copy. We don't want to mutate the existing query.
cmd = *(s.safeOp.query.(*getLastError))
if cmd.W == nil {
cmd.W = w
} else if safe.WMode != "" {
cmd.W = safe.WMode
} else if i, ok := cmd.W.(int); ok && safe.W > i {
cmd.W = safe.W
}
if safe.WTimeout > 0 && safe.WTimeout < cmd.WTimeout {
cmd.WTimeout = safe.WTimeout
}
if safe.FSync {
cmd.FSync = true
cmd.J = false
} else if safe.J && !cmd.FSync {
cmd.J = true
}
}
s.safeOp = &queryOp{
query: &cmd,
collection: "admin.$cmd",
limit: -1,
}
}
// Run issues the provided command on the "admin" database and
// and unmarshals its result in the respective argument. The cmd
// argument may be either a string with the command name itself, in
// which case an empty document of the form bson.M{cmd: 1} will be used,
// or it may be a full command document.
//
// Note that MongoDB considers the first marshalled key as the command
// name, so when providing a command with options, it's important to
// use an ordering-preserving document, such as a struct value or an
// instance of bson.D. For instance:
//
// db.Run(bson.D{{"create", "mycollection"}, {"size", 1024}})
//
// For commands on arbitrary databases, see the Run method in
// the Database type.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Commands
// http://www.mongodb.org/display/DOCS/List+of+Database+CommandSkips
//
func (s *Session) Run(cmd interface{}, result interface{}) error {
return s.DB("admin").Run(cmd, result)
}
// SelectServers restricts communication to servers configured with the
// given tags. For example, the following statement restricts servers
// used for reading operations to those with both tag "disk" set to
// "ssd" and tag "rack" set to 1:
//
// session.SelectSlaves(bson.D{{"disk", "ssd"}, {"rack", 1}})
//
// Multiple sets of tags may be provided, in which case the used server
// must match all tags within any one set.
//
// If a connection was previously assigned to the session due to the
// current session mode (see Session.SetMode), the tag selection will
// only be enforced after the session is refreshed.
//
// Relevant documentation:
//
// http://docs.mongodb.org/manual/tutorial/configure-replica-set-tag-sets
//
func (s *Session) SelectServers(tags ...bson.D) {
s.m.Lock()
s.queryConfig.op.serverTags = tags
s.m.Unlock()
}
// Ping runs a trivial ping command just to get in touch with the server.
func (s *Session) Ping() error {
return s.Run("ping", nil)
}
// Fsync flushes in-memory writes to disk on the server the session
// is established with. If async is true, the call returns immediately,
// otherwise it returns after the flush has been made.
func (s *Session) Fsync(async bool) error {
return s.Run(bson.D{{"fsync", 1}, {"async", async}}, nil)
}
// FsyncLock locks all writes in the specific server the session is
// established with and returns. Any writes attempted to the server
// after it is successfully locked will block until FsyncUnlock is
// called for the same server.
//
// This method works on secondaries as well, preventing the oplog from
// being flushed while the server is locked, but since only the server
// connected to is locked, for locking specific secondaries it may be
// necessary to establish a connection directly to the secondary (see
// Dial's connect=direct option).
//
// As an important caveat, note that once a write is attempted and
// blocks, follow up reads will block as well due to the way the
// lock is internally implemented in the server. More details at:
//
// https://jira.mongodb.org/browse/SERVER-4243
//
// FsyncLock is often used for performing consistent backups of
// the database files on disk.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/fsync+Command
// http://www.mongodb.org/display/DOCS/Backups
//
func (s *Session) FsyncLock() error {
return s.Run(bson.D{{"fsync", 1}, {"lock", true}}, nil)
}
// FsyncUnlock releases the server for writes. See FsyncLock for details.
func (s *Session) FsyncUnlock() error {
return s.DB("admin").C("$cmd.sys.unlock").Find(nil).One(nil) // WTF?
}
// Find prepares a query using the provided document. The document may be a
// map or a struct value capable of being marshalled with bson. The map
// may be a generic one using interface{} for its key and/or values, such as
// bson.M, or it may be a properly typed map. Providing nil as the document
// is equivalent to providing an empty document such as bson.M{}.
//
// Further details of the query may be tweaked using the resulting Query value,
// and then executed to retrieve results using methods such as One, For,
// Iter, or Tail.
//
// In case the resulting document includes a field named $err or errmsg, which
// are standard ways for MongoDB to return query errors, the returned err will
// be set to a *QueryError value including the Err message and the Code. In
// those cases, the result argument is still unmarshalled into with the
// received document so that any other custom values may be obtained if
// desired.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Querying
// http://www.mongodb.org/display/DOCS/Advanced+Queries
//
func (c *Collection) Find(query interface{}) *Query {
session := c.Database.Session
session.m.RLock()
q := &Query{session: session, query: session.queryConfig}
session.m.RUnlock()
q.op.query = query
q.op.collection = c.FullName
return q
}
// FindId is a convenience helper equivalent to:
//
// query := collection.Find(bson.M{"_id": id})
//
// See the Find method for more details.
func (c *Collection) FindId(id interface{}) *Query {
return c.Find(bson.D{{"_id", id}})
}
type Pipe struct {
session *Session
collection *Collection
pipeline interface{}
}
// Pipe prepares a pipeline to aggregate. The pipeline document
// must be a slice built in terms of the aggregation framework language.
//
// For example:
//
// pipe := collection.Pipe([]bson.M{{"$match": bson.M{"name": "Otavio"}}})
// iter := pipe.Iter()
//
// Relevant documentation:
//
// http://docs.mongodb.org/manual/reference/aggregation
// http://docs.mongodb.org/manual/applications/aggregation
// http://docs.mongodb.org/manual/tutorial/aggregation-examples
//
func (c *Collection) Pipe(pipeline interface{}) *Pipe {
session := c.Database.Session
return &Pipe{
session: session,
collection: c,
pipeline: pipeline,
}
}
// Iter executes the pipeline and returns an iterator capable of going
// over all the generated results.
func (p *Pipe) Iter() *Iter {
iter := &Iter{
session: p.session,
timeout: -1,
}
iter.gotReply.L = &iter.m
var result struct{ Result []bson.Raw }
c := p.collection
iter.err = c.Database.Run(bson.D{{"aggregate", c.Name}, {"pipeline", p.pipeline}}, &result)
if iter.err != nil {
return iter
}
for i := range result.Result {
iter.docData.Push(result.Result[i].Data)
}
return iter
}
// All works like Iter.All.
func (p *Pipe) All(result interface{}) error {
return p.Iter().All(result)
}
// One executes the pipeline and unmarshals the first item from the
// result set into the result parameter.
// It returns ErrNotFound if no items are generated by the pipeline.
func (p *Pipe) One(result interface{}) error {
iter := p.Iter()
if iter.Next(result) {
return nil
}
if err := iter.Err(); err != nil {
return err
}
return ErrNotFound
}
type LastError struct {
Err string
Code, N, Waited int
FSyncFiles int `bson:"fsyncFiles"`
WTimeout bool
UpdatedExisting bool `bson:"updatedExisting"`
UpsertedId interface{} `bson:"upserted"`
}
func (err *LastError) Error() string {
return err.Err
}
type queryError struct {
Err string "$err"
ErrMsg string
Assertion string
Code int
AssertionCode int "assertionCode"
LastError *LastError "lastErrorObject"
}
type QueryError struct {
Code int
Message string
Assertion bool
}
func (err *QueryError) Error() string {
return err.Message
}
// IsDup returns whether err informs of a duplicate key error because
// a primary key index or a secondary unique index already has an entry
// with the given value.
func IsDup(err error) bool {
// Besides being handy, helps with MongoDB bugs SERVER-7164 and SERVER-11493.
// What follows makes me sad. Hopefully conventions will be more clear over time.
switch e := err.(type) {
case *LastError:
return e.Code == 11000 || e.Code == 11001 || e.Code == 12582 || e.Code == 16460 && strings.Contains(e.Err, " E11000 ")
case *QueryError:
return e.Code == 11000 || e.Code == 11001 || e.Code == 12582
}
return false
}
// Insert inserts one or more documents in the respective collection. In
// case the session is in safe mode (see the SetSafe method) and an error
// happens while inserting the provided documents, the returned error will
// be of type *LastError.
func (c *Collection) Insert(docs ...interface{}) error {
_, err := c.writeQuery(&insertOp{c.FullName, docs, 0})
return err
}
// Update finds a single document matching the provided selector document
// and modifies it according to the update document.
// If the session is in safe mode (see SetSafe) a ErrNotFound error is
// returned if a document isn't found, or a value of type *LastError
// when some other error is detected.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Updating
// http://www.mongodb.org/display/DOCS/Atomic+Operations
//
func (c *Collection) Update(selector interface{}, update interface{}) error {
lerr, err := c.writeQuery(&updateOp{c.FullName, selector, update, 0})
if err == nil && lerr != nil && !lerr.UpdatedExisting {
return ErrNotFound
}
return err
}
// UpdateId is a convenience helper equivalent to:
//
// err := collection.Update(bson.M{"_id": id}, update)
//
// See the Update method for more details.
func (c *Collection) UpdateId(id interface{}, update interface{}) error {
return c.Update(bson.D{{"_id", id}}, update)
}
// ChangeInfo holds details about the outcome of an update operation.
type ChangeInfo struct {
Updated int // Number of existing documents updated
Removed int // Number of documents removed
UpsertedId interface{} // Upserted _id field, when not explicitly provided
}
// UpdateAll finds all documents matching the provided selector document
// and modifies them according to the update document.
// If the session is in safe mode (see SetSafe) details of the executed
// operation are returned in info or an error of type *LastError when
// some problem is detected. It is not an error for the update to not be
// applied on any documents because the selector doesn't match.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Updating
// http://www.mongodb.org/display/DOCS/Atomic+Operations
//
func (c *Collection) UpdateAll(selector interface{}, update interface{}) (info *ChangeInfo, err error) {
lerr, err := c.writeQuery(&updateOp{c.FullName, selector, update, 2})
if err == nil && lerr != nil {
info = &ChangeInfo{Updated: lerr.N}
}
return info, err
}
// Upsert finds a single document matching the provided selector document
// and modifies it according to the update document. If no document matching
// the selector is found, the update document is applied to the selector
// document and the result is inserted in the collection.
// If the session is in safe mode (see SetSafe) details of the executed
// operation are returned in info, or an error of type *LastError when
// some problem is detected.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Updating
// http://www.mongodb.org/display/DOCS/Atomic+Operations
//
func (c *Collection) Upsert(selector interface{}, update interface{}) (info *ChangeInfo, err error) {
lerr, err := c.writeQuery(&updateOp{c.FullName, selector, update, 1})
if err == nil && lerr != nil {
info = &ChangeInfo{}
if lerr.UpdatedExisting {
info.Updated = lerr.N
} else {
info.UpsertedId = lerr.UpsertedId
}
}
return info, err
}
// UpsertId is a convenience helper equivalent to:
//
// info, err := collection.Upsert(bson.M{"_id": id}, update)
//
// See the Upsert method for more details.
func (c *Collection) UpsertId(id interface{}, update interface{}) (info *ChangeInfo, err error) {
return c.Upsert(bson.D{{"_id", id}}, update)
}
// Remove finds a single document matching the provided selector document
// and removes it from the database.
// If the session is in safe mode (see SetSafe) a ErrNotFound error is
// returned if a document isn't found, or a value of type *LastError
// when some other error is detected.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Removing
//
func (c *Collection) Remove(selector interface{}) error {
lerr, err := c.writeQuery(&deleteOp{c.FullName, selector, 1})
if err == nil && lerr != nil && lerr.N == 0 {
return ErrNotFound
}
return err
}
// RemoveId is a convenience helper equivalent to:
//
// err := collection.Remove(bson.M{"_id": id})
//
// See the Remove method for more details.
func (c *Collection) RemoveId(id interface{}) error {
return c.Remove(bson.D{{"_id", id}})
}
// RemoveAll finds all documents matching the provided selector document
// and removes them from the database. In case the session is in safe mode
// (see the SetSafe method) and an error happens when attempting the change,
// the returned error will be of type *LastError.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Removing
//
func (c *Collection) RemoveAll(selector interface{}) (info *ChangeInfo, err error) {
lerr, err := c.writeQuery(&deleteOp{c.FullName, selector, 0})
if err == nil && lerr != nil {
info = &ChangeInfo{Removed: lerr.N}
}
return info, err
}
// DropDatabase removes the entire database including all of its collections.
func (db *Database) DropDatabase() error {
return db.Run(bson.D{{"dropDatabase", 1}}, nil)
}
// DropCollection removes the entire collection including all of its documents.
func (c *Collection) DropCollection() error {
return c.Database.Run(bson.D{{"drop", c.Name}}, nil)
}
// The CollectionInfo type holds metadata about a collection.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/createCollection+Command
// http://www.mongodb.org/display/DOCS/Capped+Collections
//
type CollectionInfo struct {
// DisableIdIndex prevents the automatic creation of the index
// on the _id field for the collection.
DisableIdIndex bool
// ForceIdIndex enforces the automatic creation of the index
// on the _id field for the collection. Capped collections,
// for example, do not have such an index by default.
ForceIdIndex bool
// If Capped is true new documents will replace old ones when
// the collection is full. MaxBytes must necessarily be set
// to define the size when the collection wraps around.
// MaxDocs optionally defines the number of documents when it
// wraps, but MaxBytes still needs to be set.
Capped bool
MaxBytes int
MaxDocs int
}
// Create explicitly creates the c collection with details of info.
// MongoDB creates collections automatically on use, so this method
// is only necessary when creating collection with non-default
// characteristics, such as capped collections.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/createCollection+Command
// http://www.mongodb.org/display/DOCS/Capped+Collections
//
func (c *Collection) Create(info *CollectionInfo) error {
cmd := make(bson.D, 0, 4)
cmd = append(cmd, bson.DocElem{"create", c.Name})
if info.Capped {
if info.MaxBytes < 1 {
return fmt.Errorf("Collection.Create: with Capped, MaxBytes must also be set")
}
cmd = append(cmd, bson.DocElem{"capped", true})
cmd = append(cmd, bson.DocElem{"size", info.MaxBytes})
if info.MaxDocs > 0 {
cmd = append(cmd, bson.DocElem{"max", info.MaxDocs})
}
}
if info.DisableIdIndex {
cmd = append(cmd, bson.DocElem{"autoIndexId", false})
}
if info.ForceIdIndex {
cmd = append(cmd, bson.DocElem{"autoIndexId", true})
}
return c.Database.Run(cmd, nil)
}
// Batch sets the batch size used when fetching documents from the database.
// It's possible to change this setting on a per-session basis as well, using
// the Batch method of Session.
//
// The default batch size is defined by the database itself. As of this
// writing, MongoDB will use an initial size of min(100 docs, 4MB) on the
// first batch, and 4MB on remaining ones.
func (q *Query) Batch(n int) *Query {
if n == 1 {
// Server interprets 1 as -1 and closes the cursor (!?)
n = 2
}
q.m.Lock()
q.op.limit = int32(n)
q.m.Unlock()
return q
}
// Prefetch sets the point at which the next batch of results will be requested.
// When there are p*batch_size remaining documents cached in an Iter, the next
// batch will be requested in background. For instance, when using this:
//
// query.Batch(200).Prefetch(0.25)
//
// and there are only 50 documents cached in the Iter to be processed, the
// next batch of 200 will be requested. It's possible to change this setting on
// a per-session basis as well, using the SetPrefetch method of Session.
//
// The default prefetch value is 0.25.
func (q *Query) Prefetch(p float64) *Query {
q.m.Lock()
q.prefetch = p
q.m.Unlock()
return q
}
// Skip skips over the n initial documents from the query results. Note that
// this only makes sense with capped collections where documents are naturally
// ordered by insertion time, or with sorted results.
func (q *Query) Skip(n int) *Query {
q.m.Lock()
q.op.skip = int32(n)
q.m.Unlock()
return q
}
// Limit restricts the maximum number of documents retrieved to n, and also
// changes the batch size to the same value. Once n documents have been
// returned by Next, the following call will return ErrNotFound.
func (q *Query) Limit(n int) *Query {
q.m.Lock()
switch {
case n == 1:
q.limit = 1
q.op.limit = -1
case n == math.MinInt32: // -MinInt32 == -MinInt32
q.limit = math.MaxInt32
q.op.limit = math.MinInt32 + 1
case n < 0:
q.limit = int32(-n)
q.op.limit = int32(n)
default:
q.limit = int32(n)
q.op.limit = int32(n)
}
q.m.Unlock()
return q
}
// Select enables selecting which fields should be retrieved for the results
// found. For example, the following query would only retrieve the name field:
//
// err := collection.Find(nil).Select(bson.M{"name": 1}).One(&result)
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Retrieving+a+Subset+of+Fields
//
func (q *Query) Select(selector interface{}) *Query {
q.m.Lock()
q.op.selector = selector
q.m.Unlock()
return q
}
// Sort asks the database to order returned documents according to the
// provided field names. A field name may be prefixed by - (minus) for
// it to be sorted in reverse order.
//
// For example:
//
// query1 := collection.Find(nil).Sort("firstname", "lastname")
// query2 := collection.Find(nil).Sort("-age")
// query3 := collection.Find(nil).Sort("$natural")
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Sorting+and+Natural+Order
//
func (q *Query) Sort(fields ...string) *Query {
// TODO // query4 := collection.Find(nil).Sort("score:{$meta:textScore}")
q.m.Lock()
var order bson.D
for _, field := range fields {
n := 1
if field != "" {
switch field[0] {
case '+':
field = field[1:]
case '-':
n = -1
field = field[1:]
}
}
if field == "" {
panic("Sort: empty field name")
}
order = append(order, bson.DocElem{field, n})
}
q.op.options.OrderBy = order
q.op.hasOptions = true
q.m.Unlock()
return q
}
// Explain returns a number of details about how the MongoDB server would
// execute the requested query, such as the number of objects examined,
// the number of time the read lock was yielded to allow writes to go in,
// and so on.
//
// For example:
//
// m := bson.M{}
// err := collection.Find(bson.M{"filename": name}).Explain(m)
// if err == nil {
// fmt.Printf("Explain: %#v\n", m)
// }
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Optimization
// http://www.mongodb.org/display/DOCS/Query+Optimizer
//
func (q *Query) Explain(result interface{}) error {
q.m.Lock()
clone := &Query{session: q.session, query: q.query}
q.m.Unlock()
clone.op.options.Explain = true
clone.op.hasOptions = true
if clone.op.limit > 0 {
clone.op.limit = -q.op.limit
}
iter := clone.Iter()
if iter.Next(result) {
return nil
}
return iter.Close()
}
// Hint will include an explicit "hint" in the query to force the server
// to use a specified index, potentially improving performance in some
// situations. The provided parameters are the fields that compose the
// key of the index to be used. For details on how the indexKey may be
// built, see the EnsureIndex method.
//
// For example:
//
// query := collection.Find(bson.M{"firstname": "Joe", "lastname": "Winter"})
// query.Hint("lastname", "firstname")
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Optimization
// http://www.mongodb.org/display/DOCS/Query+Optimizer
//
func (q *Query) Hint(indexKey ...string) *Query {
q.m.Lock()
_, realKey, err := parseIndexKey(indexKey)
q.op.options.Hint = realKey
q.op.hasOptions = true
q.m.Unlock()
if err != nil {
panic(err)
}
return q
}
// Snapshot will force the performed query to make use of an available
// index on the _id field to prevent the same document from being returned
// more than once in a single iteration. This might happen without this
// setting in situations when the document changes in size and thus has to
// be moved while the iteration is running.
//
// Because snapshot mode traverses the _id index, it may not be used with
// sorting or explicit hints. It also cannot use any other index for the
// query.
//
// Even with snapshot mode, items inserted or deleted during the query may
// or may not be returned; that is, this mode is not a true point-in-time
// snapshot.
//
// The same effect of Snapshot may be obtained by using any unique index on
// field(s) that will not be modified (best to use Hint explicitly too).
// A non-unique index (such as creation time) may be made unique by
// appending _id to the index when creating it.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/How+to+do+Snapshotted+Queries+in+the+Mongo+Database
//
func (q *Query) Snapshot() *Query {
q.m.Lock()
q.op.options.Snapshot = true
q.op.hasOptions = true
q.m.Unlock()
return q
}
// LogReplay enables an option that optimizes queries that are typically
// made on the MongoDB oplog for replaying it. This is an internal
// implementation aspect and most likely uninteresting for other uses.
// It has seen at least one use case, though, so it's exposed via the API.
func (q *Query) LogReplay() *Query {
q.m.Lock()
q.op.flags |= flagLogReplay
q.m.Unlock()
return q
}
func checkQueryError(fullname string, d []byte) error {
l := len(d)
if l < 16 {
return nil
}
if d[5] == '$' && d[6] == 'e' && d[7] == 'r' && d[8] == 'r' && d[9] == '\x00' && d[4] == '\x02' {
goto Error
}
if len(fullname) < 5 || fullname[len(fullname)-5:] != ".$cmd" {
return nil
}
for i := 0; i+8 < l; i++ {
if d[i] == '\x02' && d[i+1] == 'e' && d[i+2] == 'r' && d[i+3] == 'r' && d[i+4] == 'm' && d[i+5] == 's' && d[i+6] == 'g' && d[i+7] == '\x00' {
goto Error
}
}
return nil
Error:
result := &queryError{}
bson.Unmarshal(d, result)
logf("queryError: %#v\n", result)
if result.LastError != nil {
return result.LastError
}
if result.Err == "" && result.ErrMsg == "" {
return nil
}
if result.AssertionCode != 0 && result.Assertion != "" {
return &QueryError{Code: result.AssertionCode, Message: result.Assertion, Assertion: true}
}
if result.Err != "" {
return &QueryError{Code: result.Code, Message: result.Err}
}
return &QueryError{Code: result.Code, Message: result.ErrMsg}
}
// One executes the query and unmarshals the first obtained document into the
// result argument. The result must be a struct or map value capable of being
// unmarshalled into by gobson. This function blocks until either a result
// is available or an error happens. For example:
//
// err := collection.Find(bson.M{"a", 1}).One(&result)
//
// In case the resulting document includes a field named $err or errmsg, which
// are standard ways for MongoDB to return query errors, the returned err will
// be set to a *QueryError value including the Err message and the Code. In
// those cases, the result argument is still unmarshalled into with the
// received document so that any other custom values may be obtained if
// desired.
//
func (q *Query) One(result interface{}) (err error) {
q.m.Lock()
session := q.session
op := q.op // Copy.
q.m.Unlock()
socket, err := session.acquireSocket(true)
if err != nil {
return err
}
defer socket.Release()
op.flags |= session.slaveOkFlag()
op.limit = -1
data, err := socket.SimpleQuery(&op)
if err != nil {
return err
}
if data == nil {
return ErrNotFound
}
if result != nil {
err = bson.Unmarshal(data, result)
if err == nil {
debugf("Query %p document unmarshaled: %#v", q, result)
} else {
debugf("Query %p document unmarshaling failed: %#v", q, err)
return err
}
}
return checkQueryError(op.collection, data)
}
// The DBRef type implements support for the database reference MongoDB
// convention as supported by multiple drivers. This convention enables
// cross-referencing documents between collections and databases using
// a structure which includes a collection name, a document id, and
// optionally a database name.
//
// See the FindRef methods on Session and on Database.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Database+References
//
type DBRef struct {
Collection string `bson:"$ref"`
Id interface{} `bson:"$id"`
Database string `bson:"$db,omitempty"`
}
// NOTE: Order of fields for DBRef above does matter, per documentation.
// FindRef returns a query that looks for the document in the provided
// reference. If the reference includes the DB field, the document will
// be retrieved from the respective database.
//
// See also the DBRef type and the FindRef method on Session.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Database+References
//
func (db *Database) FindRef(ref *DBRef) *Query {
var c *Collection
if ref.Database == "" {
c = db.C(ref.Collection)
} else {
c = db.Session.DB(ref.Database).C(ref.Collection)
}
return c.FindId(ref.Id)
}
// FindRef returns a query that looks for the document in the provided
// reference. For a DBRef to be resolved correctly at the session level
// it must necessarily have the optional DB field defined.
//
// See also the DBRef type and the FindRef method on Database.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Database+References
//
func (s *Session) FindRef(ref *DBRef) *Query {
if ref.Database == "" {
panic(errors.New(fmt.Sprintf("Can't resolve database for %#v", ref)))
}
c := s.DB(ref.Database).C(ref.Collection)
return c.FindId(ref.Id)
}
// CollectionNames returns the collection names present in database.
func (db *Database) CollectionNames() (names []string, err error) {
c := len(db.Name) + 1
iter := db.C("system.namespaces").Find(nil).Iter()
var result *struct{ Name string }
for iter.Next(&result) {
if strings.Index(result.Name, "$") < 0 || strings.Index(result.Name, ".oplog.$") >= 0 {
names = append(names, result.Name[c:])
}
}
if err := iter.Close(); err != nil {
return nil, err
}
sort.Strings(names)
return names, nil
}
type dbNames struct {
Databases []struct {
Name string
Empty bool
}
}
// DatabaseNames returns the names of non-empty databases present in the cluster.
func (s *Session) DatabaseNames() (names []string, err error) {
var result dbNames
err = s.Run("listDatabases", &result)
if err != nil {
return nil, err
}
for _, db := range result.Databases {
if !db.Empty {
names = append(names, db.Name)
}
}
sort.Strings(names)
return names, nil
}
// Iter executes the query and returns an iterator capable of going over all
// the results. Results will be returned in batches of configurable
// size (see the Batch method) and more documents will be requested when a
// configurable number of documents is iterated over (see the Prefetch method).
func (q *Query) Iter() *Iter {
q.m.Lock()
session := q.session
op := q.op
prefetch := q.prefetch
limit := q.limit
q.m.Unlock()
iter := &Iter{
session: session,
prefetch: prefetch,
limit: limit,
timeout: -1,
}
iter.gotReply.L = &iter.m
iter.op.collection = op.collection
iter.op.limit = op.limit
iter.op.replyFunc = iter.replyFunc()
iter.docsToReceive++
op.replyFunc = iter.op.replyFunc
op.flags |= session.slaveOkFlag()
socket, err := session.acquireSocket(true)
if err != nil {
iter.err = err
} else {
iter.server = socket.Server()
err = socket.Query(&op)
if err != nil {
// Must lock as the query above may call replyFunc.
iter.m.Lock()
iter.err = err
iter.m.Unlock()
}
socket.Release()
}
return iter
}
// Tail returns a tailable iterator. Unlike a normal iterator, a
// tailable iterator may wait for new values to be inserted in the
// collection once the end of the current result set is reached,
// A tailable iterator may only be used with capped collections.
//
// The timeout parameter indicates how long Next will block waiting
// for a result before timing out. If set to -1, Next will not
// timeout, and will continue waiting for a result for as long as
// the cursor is valid and the session is not closed. If set to 0,
// Next times out as soon as it reaches the end of the result set.
// Otherwise, Next will wait for at least the given number of
// seconds for a new document to be available before timing out.
//
// On timeouts, Next will unblock and return false, and the Timeout
// method will return true if called. In these cases, Next may still
// be called again on the same iterator to check if a new value is
// available at the current cursor position, and again it will block
// according to the specified timeoutSecs. If the cursor becomes
// invalid, though, both Next and Timeout will return false and
// the query must be restarted.
//
// The following example demonstrates timeout handling and query
// restarting:
//
// iter := collection.Find(nil).Sort("$natural").Tail(5 * time.Second)
// for {
// for iter.Next(&result) {
// fmt.Println(result.Id)
// lastId = result.Id
// }
// if iter.Err() != nil {
// return iter.Close()
// }
// if iter.Timeout() {
// continue
// }
// query := collection.Find(bson.M{"_id": bson.M{"$gt": lastId}})
// iter = query.Sort("$natural").Tail(5 * time.Second)
// }
// iter.Close()
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Tailable+Cursors
// http://www.mongodb.org/display/DOCS/Capped+Collections
// http://www.mongodb.org/display/DOCS/Sorting+and+Natural+Order
//
func (q *Query) Tail(timeout time.Duration) *Iter {
q.m.Lock()
session := q.session
op := q.op
prefetch := q.prefetch
q.m.Unlock()
iter := &Iter{session: session, prefetch: prefetch}
iter.gotReply.L = &iter.m
iter.timeout = timeout
iter.op.collection = op.collection
iter.op.limit = op.limit
iter.op.replyFunc = iter.replyFunc()
iter.docsToReceive++
op.replyFunc = iter.op.replyFunc
op.flags |= flagTailable | flagAwaitData | session.slaveOkFlag()
socket, err := session.acquireSocket(true)
if err != nil {
iter.err = err
} else {
iter.server = socket.Server()
err = socket.Query(&op)
if err != nil {
// Must lock as the query above may call replyFunc.
iter.m.Lock()
iter.err = err
iter.m.Unlock()
}
socket.Release()
}
return iter
}
func (s *Session) slaveOkFlag() (flag queryOpFlags) {
s.m.RLock()
if s.slaveOk {
flag = flagSlaveOk
}
s.m.RUnlock()
return
}
// Err returns nil if no errors happened during iteration, or the actual
// error otherwise.
//
// In case a resulting document included a field named $err or errmsg, which are
// standard ways for MongoDB to report an improper query, the returned value has
// a *QueryError type, and includes the Err message and the Code.
func (iter *Iter) Err() error {
iter.m.Lock()
err := iter.err
iter.m.Unlock()
if err == ErrNotFound {
return nil
}
return err
}
// Close kills the server cursor used by the iterator, if any, and returns
// nil if no errors happened during iteration, or the actual error otherwise.
//
// Server cursors are automatically closed at the end of an iteration, which
// means close will do nothing unless the iteration was interrupted before
// the server finished sending results to the driver. If Close is not called
// in such a situation, the cursor will remain available at the server until
// the default cursor timeout period is reached. No further problems arise.
//
// Close is idempotent. That means it can be called repeatedly and will
// return the same result every time.
//
// In case a resulting document included a field named $err or errmsg, which are
// standard ways for MongoDB to report an improper query, the returned value has
// a *QueryError type.
func (iter *Iter) Close() error {
iter.m.Lock()
iter.killCursor()
err := iter.err
iter.m.Unlock()
if err == ErrNotFound {
return nil
}
return err
}
func (iter *Iter) killCursor() error {
if iter.op.cursorId != 0 {
socket, err := iter.acquireSocket()
if err == nil {
// TODO Batch kills.
err = socket.Query(&killCursorsOp{[]int64{iter.op.cursorId}})
socket.Release()
}
if err != nil && (iter.err == nil || iter.err == ErrNotFound) {
iter.err = err
}
iter.op.cursorId = 0
return err
}
return nil
}
// Timeout returns true if Next returned false due to a timeout of
// a tailable cursor. In those cases, Next may be called again to continue
// the iteration at the previous cursor position.
func (iter *Iter) Timeout() bool {
iter.m.Lock()
result := iter.timedout
iter.m.Unlock()
return result
}
// Next retrieves the next document from the result set, blocking if necessary.
// This method will also automatically retrieve another batch of documents from
// the server when the current one is exhausted, or before that in background
// if pre-fetching is enabled (see the Query.Prefetch and Session.SetPrefetch
// methods).
//
// Next returns true if a document was successfully unmarshalled onto result,
// and false at the end of the result set or if an error happened.
// When Next returns false, the Err method should be called to verify if
// there was an error during iteration.
//
// For example:
//
// iter := collection.Find(nil).Iter()
// for iter.Next(&result) {
// fmt.Printf("Result: %v\n", result.Id)
// }
// if err := iter.Close(); err != nil {
// return err
// }
//
func (iter *Iter) Next(result interface{}) bool {
iter.m.Lock()
iter.timedout = false
timeout := time.Time{}
for iter.err == nil && iter.docData.Len() == 0 && (iter.docsToReceive > 0 || iter.op.cursorId != 0) {
if iter.docsToReceive == 0 {
if iter.timeout >= 0 {
if timeout.IsZero() {
timeout = time.Now().Add(iter.timeout)
}
if time.Now().After(timeout) {
iter.timedout = true
iter.m.Unlock()
return false
}
}
iter.getMore()
if iter.err != nil {
break
}
}
iter.gotReply.Wait()
}
// Exhaust available data before reporting any errors.
if docData, ok := iter.docData.Pop().([]byte); ok {
if iter.limit > 0 {
iter.limit--
if iter.limit == 0 {
if iter.docData.Len() > 0 {
iter.m.Unlock()
panic(fmt.Errorf("data remains after limit exhausted: %d", iter.docData.Len()))
}
iter.err = ErrNotFound
if iter.killCursor() != nil {
iter.m.Unlock()
return false
}
}
}
if iter.op.cursorId != 0 && iter.err == nil {
if iter.docsBeforeMore == 0 {
iter.getMore()
}
iter.docsBeforeMore-- // Goes negative.
}
iter.m.Unlock()
err := bson.Unmarshal(docData, result)
if err != nil {
debugf("Iter %p document unmarshaling failed: %#v", iter, err)
iter.m.Lock()
if iter.err == nil {
iter.err = err
}
iter.m.Unlock()
return false
}
debugf("Iter %p document unmarshaled: %#v", iter, result)
// XXX Only have to check first document for a query error?
err = checkQueryError(iter.op.collection, docData)
if err != nil {
iter.m.Lock()
if iter.err == nil {
iter.err = err
}
iter.m.Unlock()
return false
}
return true
} else if iter.err != nil {
debugf("Iter %p returning false: %s", iter, iter.err)
iter.m.Unlock()
return false
} else if iter.op.cursorId == 0 {
iter.err = ErrNotFound
debugf("Iter %p exhausted with cursor=0", iter)
iter.m.Unlock()
return false
}
panic("unreachable")
}
// All retrieves all documents from the result set into the provided slice
// and closes the iterator.
//
// The result argument must necessarily be the address for a slice. The slice
// may be nil or previously allocated.
//
// WARNING: Obviously, All must not be used with result sets that may be
// potentially large, since it may consume all memory until the system
// crashes. Consider building the query with a Limit clause to ensure the
// result size is bounded.
//
// For instance:
//
// var result []struct{ Value int }
// iter := collection.Find(nil).Limit(100).Iter()
// err := iter.All(&result)
// if err != nil {
// return err
// }
//
func (iter *Iter) All(result interface{}) error {
resultv := reflect.ValueOf(result)
if resultv.Kind() != reflect.Ptr || resultv.Elem().Kind() != reflect.Slice {
panic("result argument must be a slice address")
}
slicev := resultv.Elem()
slicev = slicev.Slice(0, slicev.Cap())
elemt := slicev.Type().Elem()
i := 0
for {
if slicev.Len() == i {
elemp := reflect.New(elemt)
if !iter.Next(elemp.Interface()) {
break
}
slicev = reflect.Append(slicev, elemp.Elem())
slicev = slicev.Slice(0, slicev.Cap())
} else {
if !iter.Next(slicev.Index(i).Addr().Interface()) {
break
}
}
i++
}
resultv.Elem().Set(slicev.Slice(0, i))
return iter.Close()
}
// All works like Iter.All.
func (q *Query) All(result interface{}) error {
return q.Iter().All(result)
}
// The For method is obsolete and will be removed in a future release.
// See Iter as an elegant replacement.
func (q *Query) For(result interface{}, f func() error) error {
return q.Iter().For(result, f)
}
// The For method is obsolete and will be removed in a future release.
// See Iter as an elegant replacement.
func (iter *Iter) For(result interface{}, f func() error) (err error) {
valid := false
v := reflect.ValueOf(result)
if v.Kind() == reflect.Ptr {
v = v.Elem()
switch v.Kind() {
case reflect.Map, reflect.Ptr, reflect.Interface, reflect.Slice:
valid = v.IsNil()
}
}
if !valid {
panic("For needs a pointer to nil reference value. See the documentation.")
}
zero := reflect.Zero(v.Type())
for {
v.Set(zero)
if !iter.Next(result) {
break
}
err = f()
if err != nil {
return err
}
}
return iter.Err()
}
func (iter *Iter) acquireSocket() (*mongoSocket, error) {
socket, err := iter.session.acquireSocket(true)
if err != nil {
return nil, err
}
if socket.Server() != iter.server {
// Socket server changed during iteration. This may happen
// with Eventual sessions, if a Refresh is done, or if a
// monotonic session gets a write and shifts from secondary
// to primary. Our cursor is in a specific server, though.
iter.session.m.Lock()
sockTimeout := iter.session.sockTimeout
iter.session.m.Unlock()
socket.Release()
socket, _, err = iter.server.AcquireSocket(0, sockTimeout)
if err != nil {
return nil, err
}
err := iter.session.socketLogin(socket)
if err != nil {
socket.Release()
return nil, err
}
}
return socket, nil
}
func (iter *Iter) getMore() {
socket, err := iter.acquireSocket()
if err != nil {
iter.err = err
return
}
defer socket.Release()
debugf("Iter %p requesting more documents", iter)
if iter.limit > 0 {
limit := iter.limit - int32(iter.docsToReceive) - int32(iter.docData.Len())
if limit < iter.op.limit {
iter.op.limit = limit
}
}
if err := socket.Query(&iter.op); err != nil {
iter.err = err
}
iter.docsToReceive++
}
type countCmd struct {
Count string
Query interface{}
Limit int32 ",omitempty"
Skip int32 ",omitempty"
}
// Count returns the total number of documents in the result set.
func (q *Query) Count() (n int, err error) {
q.m.Lock()
session := q.session
op := q.op
limit := q.limit
q.m.Unlock()
c := strings.Index(op.collection, ".")
if c < 0 {
return 0, errors.New("Bad collection name: " + op.collection)
}
dbname := op.collection[:c]
cname := op.collection[c+1:]
result := struct{ N int }{}
err = session.DB(dbname).Run(countCmd{cname, op.query, limit, op.skip}, &result)
return result.N, err
}
// Count returns the total number of documents in the collection.
func (c *Collection) Count() (n int, err error) {
return c.Find(nil).Count()
}
type distinctCmd struct {
Collection string "distinct"
Key string
Query interface{} ",omitempty"
}
// Distinct returns a list of distinct values for the given key within
// the result set. The list of distinct values will be unmarshalled
// in the "values" key of the provided result parameter.
//
// For example:
//
// var result []int
// err := collection.Find(bson.M{"gender": "F"}).Distinct("age", &result)
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/Aggregation
//
func (q *Query) Distinct(key string, result interface{}) error {
q.m.Lock()
session := q.session
op := q.op // Copy.
q.m.Unlock()
c := strings.Index(op.collection, ".")
if c < 0 {
return errors.New("Bad collection name: " + op.collection)
}
dbname := op.collection[:c]
cname := op.collection[c+1:]
var doc struct{ Values bson.Raw }
err := session.DB(dbname).Run(distinctCmd{cname, key, op.query}, &doc)
if err != nil {
return err
}
return doc.Values.Unmarshal(result)
}
type mapReduceCmd struct {
Collection string "mapreduce"
Map string ",omitempty"
Reduce string ",omitempty"
Finalize string ",omitempty"
Limit int32 ",omitempty"
Out interface{}
Query interface{} ",omitempty"
Sort interface{} ",omitempty"
Scope interface{} ",omitempty"
Verbose bool ",omitempty"
}
type mapReduceResult struct {
Results bson.Raw
Result bson.Raw
TimeMillis int64 "timeMillis"
Counts struct{ Input, Emit, Output int }
Ok bool
Err string
Timing *MapReduceTime
}
type MapReduce struct {
Map string // Map Javascript function code (required)
Reduce string // Reduce Javascript function code (required)
Finalize string // Finalize Javascript function code (optional)
Out interface{} // Output collection name or document. If nil, results are inlined into the result parameter.
Scope interface{} // Optional global scope for Javascript functions
Verbose bool
}
type MapReduceInfo struct {
InputCount int // Number of documents mapped
EmitCount int // Number of times reduce called emit
OutputCount int // Number of documents in resulting collection
Database string // Output database, if results are not inlined
Collection string // Output collection, if results are not inlined
Time int64 // Time to run the job, in nanoseconds
VerboseTime *MapReduceTime // Only defined if Verbose was true
}
type MapReduceTime struct {
Total int64 // Total time, in nanoseconds
Map int64 "mapTime" // Time within map function, in nanoseconds
EmitLoop int64 "emitLoop" // Time within the emit/map loop, in nanoseconds
}
// MapReduce executes a map/reduce job for documents covered by the query.
// That kind of job is suitable for very flexible bulk aggregation of data
// performed at the server side via Javascript functions.
//
// Results from the job may be returned as a result of the query itself
// through the result parameter in case they'll certainly fit in memory
// and in a single document. If there's the possibility that the amount
// of data might be too large, results must be stored back in an alternative
// collection or even a separate database, by setting the Out field of the
// provided MapReduce job. In that case, provide nil as the result parameter.
//
// These are some of the ways to set Out:
//
// nil
// Inline results into the result parameter.
//
// bson.M{"replace": "mycollection"}
// The output will be inserted into a collection which replaces any
// existing collection with the same name.
//
// bson.M{"merge": "mycollection"}
// This option will merge new data into the old output collection. In
// other words, if the same key exists in both the result set and the
// old collection, the new key will overwrite the old one.
//
// bson.M{"reduce": "mycollection"}
// If documents exist for a given key in the result set and in the old
// collection, then a reduce operation (using the specified reduce
// function) will be performed on the two values and the result will be
// written to the output collection. If a finalize function was
// provided, this will be run after the reduce as well.
//
// bson.M{...., "db": "mydb"}
// Any of the above options can have the "db" key included for doing
// the respective action in a separate database.
//
// The following is a trivial example which will count the number of
// occurrences of a field named n on each document in a collection, and
// will return results inline:
//
// job := &mgo.MapReduce{
// Map: "function() { emit(this.n, 1) }",
// Reduce: "function(key, values) { return Array.sum(values) }",
// }
// var result []struct { Id int "_id"; Value int }
// _, err := collection.Find(nil).MapReduce(job, &result)
// if err != nil {
// return err
// }
// for _, item := range result {
// fmt.Println(item.Value)
// }
//
// This function is compatible with MongoDB 1.7.4+.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/MapReduce
//
func (q *Query) MapReduce(job *MapReduce, result interface{}) (info *MapReduceInfo, err error) {
q.m.Lock()
session := q.session
op := q.op // Copy.
limit := q.limit
q.m.Unlock()
c := strings.Index(op.collection, ".")
if c < 0 {
return nil, errors.New("Bad collection name: " + op.collection)
}
dbname := op.collection[:c]
cname := op.collection[c+1:]
cmd := mapReduceCmd{
Collection: cname,
Map: job.Map,
Reduce: job.Reduce,
Finalize: job.Finalize,
Out: fixMROut(job.Out),
Scope: job.Scope,
Verbose: job.Verbose,
Query: op.query,
Sort: op.options.OrderBy,
Limit: limit,
}
if cmd.Out == nil {
cmd.Out = bson.M{"inline": 1}
}
var doc mapReduceResult
err = session.DB(dbname).Run(&cmd, &doc)
if err != nil {
return nil, err
}
if doc.Err != "" {
return nil, errors.New(doc.Err)
}
info = &MapReduceInfo{
InputCount: doc.Counts.Input,
EmitCount: doc.Counts.Emit,
OutputCount: doc.Counts.Output,
Time: doc.TimeMillis * 1e6,
}
if doc.Result.Kind == 0x02 {
err = doc.Result.Unmarshal(&info.Collection)
info.Database = dbname
} else if doc.Result.Kind == 0x03 {
var v struct{ Collection, Db string }
err = doc.Result.Unmarshal(&v)
info.Collection = v.Collection
info.Database = v.Db
}
if doc.Timing != nil {
info.VerboseTime = doc.Timing
info.VerboseTime.Total *= 1e6
info.VerboseTime.Map *= 1e6
info.VerboseTime.EmitLoop *= 1e6
}
if err != nil {
return nil, err
}
if result != nil {
return info, doc.Results.Unmarshal(result)
}
return info, nil
}
// The "out" option in the MapReduce command must be ordered. This was
// found after the implementation was accepting maps for a long time,
// so rather than breaking the API, we'll fix the order if necessary.
// Details about the order requirement may be seen in MongoDB's code:
//
// http://goo.gl/L8jwJX
//
func fixMROut(out interface{}) interface{} {
outv := reflect.ValueOf(out)
if outv.Kind() != reflect.Map || outv.Type().Key() != reflect.TypeOf("") {
return out
}
outs := make(bson.D, outv.Len())
outTypeIndex := -1
for i, k := range outv.MapKeys() {
ks := k.String()
outs[i].Name = ks
outs[i].Value = outv.MapIndex(k).Interface()
switch ks {
case "normal", "replace", "merge", "reduce", "inline":
outTypeIndex = i
}
}
if outTypeIndex > 0 {
outs[0], outs[outTypeIndex] = outs[outTypeIndex], outs[0]
}
return outs
}
// Change holds fields for running a findAndModify MongoDB command via
// the Query.Apply method.
type Change struct {
Update interface{} // The update document
Upsert bool // Whether to insert in case the document isn't found
Remove bool // Whether to remove the document found rather than updating
ReturnNew bool // Should the modified document be returned rather than the old one
}
type findModifyCmd struct {
Collection string "findAndModify"
Query, Update, Sort, Fields interface{} ",omitempty"
Upsert, Remove, New bool ",omitempty"
}
type valueResult struct {
Value bson.Raw
LastError LastError "lastErrorObject"
}
// Apply runs the findAndModify MongoDB command, which allows updating, upserting
// or removing a document matching a query and atomically returning either the old
// version (the default) or the new version of the document (when ReturnNew is true).
// If no objects are found Apply returns ErrNotFound.
//
// The Sort and Select query methods affect the result of Apply. In case
// multiple documents match the query, Sort enables selecting which document to
// act upon by ordering it first. Select enables retrieving only a selection
// of fields of the new or old document.
//
// This simple example increments a counter and prints its new value:
//
// change := mgo.Change{
// Update: bson.M{"$inc": bson.M{"n": 1}},
// ReturnNew: true,
// }
// info, err = col.Find(M{"_id": id}).Apply(change, &doc)
// fmt.Println(doc.N)
//
// This method depends on MongoDB >= 2.0 to work properly.
//
// Relevant documentation:
//
// http://www.mongodb.org/display/DOCS/findAndModify+Command
// http://www.mongodb.org/display/DOCS/Updating
// http://www.mongodb.org/display/DOCS/Atomic+Operations
//
func (q *Query) Apply(change Change, result interface{}) (info *ChangeInfo, err error) {
q.m.Lock()
session := q.session
op := q.op // Copy.
q.m.Unlock()
c := strings.Index(op.collection, ".")
if c < 0 {
return nil, errors.New("bad collection name: " + op.collection)
}
dbname := op.collection[:c]
cname := op.collection[c+1:]
cmd := findModifyCmd{
Collection: cname,
Update: change.Update,
Upsert: change.Upsert,
Remove: change.Remove,
New: change.ReturnNew,
Query: op.query,
Sort: op.options.OrderBy,
Fields: op.selector,
}
session = session.Clone()
defer session.Close()
session.SetMode(Strong, false)
var doc valueResult
err = session.DB(dbname).Run(&cmd, &doc)
if err != nil {
if qerr, ok := err.(*QueryError); ok && qerr.Message == "No matching object found" {
return nil, ErrNotFound
}
return nil, err
}
if doc.LastError.N == 0 {
return nil, ErrNotFound
}
if doc.Value.Kind != 0x0A {
err = doc.Value.Unmarshal(result)
if err != nil {
return nil, err
}
}
info = &ChangeInfo{}
lerr := &doc.LastError
if lerr.UpdatedExisting {
info.Updated = lerr.N
} else if change.Remove {
info.Removed = lerr.N
} else if change.Upsert {
info.UpsertedId = lerr.UpsertedId
}
return info, nil
}
// The BuildInfo type encapsulates details about the running MongoDB server.
//
// Note that the VersionArray field was introduced in MongoDB 2.0+, but it is
// internally assembled from the Version information for previous versions.
// In both cases, VersionArray is guaranteed to have at least 4 entries.
type BuildInfo struct {
Version string
VersionArray []int `bson:"versionArray"` // On MongoDB 2.0+; assembled from Version otherwise
GitVersion string `bson:"gitVersion"`
SysInfo string `bson:"sysInfo"`
Bits int
Debug bool
MaxObjectSize int `bson:"maxBsonObjectSize"`
}
// VersionAtLeast returns whether the BuildInfo version is greater than or
// equal to the provided version number. If more than one number is
// provided, numbers will be considered as major, minor, and so on.
func (bi *BuildInfo) VersionAtLeast(version ...int) bool {
for i := range version {
if i == len(bi.VersionArray) {
return false
}
if bi.VersionArray[i] < version[i] {
return false
}
}
return true
}
// BuildInfo retrieves the version and other details about the
// running MongoDB server.
func (s *Session) BuildInfo() (info BuildInfo, err error) {
err = s.Run(bson.D{{"buildInfo", "1"}}, &info)
if len(info.VersionArray) == 0 {
for _, a := range strings.Split(info.Version, ".") {
i, err := strconv.Atoi(a)
if err != nil {
break
}
info.VersionArray = append(info.VersionArray, i)
}
}
for len(info.VersionArray) < 4 {
info.VersionArray = append(info.VersionArray, 0)
}
return
}
// ---------------------------------------------------------------------------
// Internal session handling helpers.
func (s *Session) acquireSocket(slaveOk bool) (*mongoSocket, error) {
// Read-only lock to check for previously reserved socket.
s.m.RLock()
if s.masterSocket != nil {
socket := s.masterSocket
socket.Acquire()
s.m.RUnlock()
return socket, nil
}
if s.slaveSocket != nil && s.slaveOk && slaveOk {
socket := s.slaveSocket
socket.Acquire()
s.m.RUnlock()
return socket, nil
}
s.m.RUnlock()
// No go. We may have to request a new socket and change the session,
// so try again but with an exclusive lock now.
s.m.Lock()
defer s.m.Unlock()
if s.masterSocket != nil {
s.masterSocket.Acquire()
return s.masterSocket, nil
}
if s.slaveSocket != nil && s.slaveOk && slaveOk {
s.slaveSocket.Acquire()
return s.slaveSocket, nil
}
// Still not good. We need a new socket.
sock, err := s.cluster().AcquireSocket(slaveOk && s.slaveOk, s.syncTimeout, s.sockTimeout, s.queryConfig.op.serverTags)
if err != nil {
return nil, err
}
// Authenticate the new socket.
if err = s.socketLogin(sock); err != nil {
sock.Release()
return nil, err
}
// Keep track of the new socket, if necessary.
// Note that, as a special case, if the Eventual session was
// not refreshed (s.slaveSocket != nil), it means the developer
// asked to preserve an existing reserved socket, so we'll
// keep a master one around too before a Refresh happens.
if s.consistency != Eventual || s.slaveSocket != nil {
s.setSocket(sock)
}
// Switch over a Monotonic session to the master.
if !slaveOk && s.consistency == Monotonic {
s.slaveOk = false
}
return sock, nil
}
// setSocket binds socket to this section.
func (s *Session) setSocket(socket *mongoSocket) {
info := socket.Acquire()
if info.Master {
if s.masterSocket != nil {
panic("setSocket(master) with existing master socket reserved")
}
s.masterSocket = socket
} else {
if s.slaveSocket != nil {
panic("setSocket(slave) with existing slave socket reserved")
}
s.slaveSocket = socket
}
}
// unsetSocket releases any slave and/or master sockets reserved.
func (s *Session) unsetSocket() {
if s.masterSocket != nil {
s.masterSocket.Release()
}
if s.slaveSocket != nil {
s.slaveSocket.Release()
}
s.masterSocket = nil
s.slaveSocket = nil
}
func (iter *Iter) replyFunc() replyFunc {
return func(err error, op *replyOp, docNum int, docData []byte) {
iter.m.Lock()
iter.docsToReceive--
if err != nil {
iter.err = err
debugf("Iter %p received an error: %s", iter, err.Error())
} else if docNum == -1 {
debugf("Iter %p received no documents (cursor=%d).", iter, op.cursorId)
if op != nil && op.cursorId != 0 {
// It's a tailable cursor.
iter.op.cursorId = op.cursorId
} else {
iter.err = ErrNotFound
}
} else {
rdocs := int(op.replyDocs)
if docNum == 0 {
iter.docsToReceive += rdocs - 1
docsToProcess := iter.docData.Len() + rdocs
if iter.limit == 0 || int32(docsToProcess) < iter.limit {
iter.docsBeforeMore = docsToProcess - int(iter.prefetch*float64(rdocs))
} else {
iter.docsBeforeMore = -1
}
iter.op.cursorId = op.cursorId
}
// XXX Handle errors and flags.
debugf("Iter %p received reply document %d/%d (cursor=%d)", iter, docNum+1, rdocs, op.cursorId)
iter.docData.Push(docData)
}
iter.gotReply.Broadcast()
iter.m.Unlock()
}
}
// writeQuery runs the given modifying operation, potentially followed up
// by a getLastError command in case the session is in safe mode. The
// LastError result is made available in lerr, and if lerr.Err is set it
// will also be returned as err.
func (c *Collection) writeQuery(op interface{}) (lerr *LastError, err error) {
s := c.Database.Session
dbname := c.Database.Name
socket, err := s.acquireSocket(dbname == "local")
if err != nil {
return nil, err
}
defer socket.Release()
s.m.RLock()
safeOp := s.safeOp
s.m.RUnlock()
if safeOp == nil {
return nil, socket.Query(op)
} else {
var mutex sync.Mutex
var replyData []byte
var replyErr error
mutex.Lock()
query := *safeOp // Copy the data.
query.collection = dbname + ".$cmd"
query.replyFunc = func(err error, reply *replyOp, docNum int, docData []byte) {
replyData = docData
replyErr = err
mutex.Unlock()
}
err = socket.Query(op, &query)
if err != nil {
return nil, err
}
mutex.Lock() // Wait.
if replyErr != nil {
return nil, replyErr // XXX TESTME
}
if hasErrMsg(replyData) {
// Looks like getLastError itself failed.
err = checkQueryError(query.collection, replyData)
if err != nil {
return nil, err
}
}
result := &LastError{}
bson.Unmarshal(replyData, &result)
debugf("Result from writing query: %#v", result)
if result.Err != "" {
return result, result
}
return result, nil
}
panic("unreachable")
}
func hasErrMsg(d []byte) bool {
l := len(d)
for i := 0; i+8 < l; i++ {
if d[i] == '\x02' && d[i+1] == 'e' && d[i+2] == 'r' && d[i+3] == 'r' && d[i+4] == 'm' && d[i+5] == 's' && d[i+6] == 'g' && d[i+7] == '\x00' {
return true
}
}
return false
}
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