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Merge pull request #888 from aaronlehmann/config-env-vars

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More flexible environment variable overrides
This commit is contained in:
Stephen Day 2015-09-10 17:01:30 -07:00
commit 1cdcc0462a
4 changed files with 288 additions and 85 deletions
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15
configuration/configuration.go
View file

@ -11,7 +11,10 @@ import (
)
// Configuration is a versioned registry configuration, intended to be provided by a yaml file, and
// optionally modified by environment variables
// optionally modified by environment variables.
//
// Note that yaml field names should never include _ characters, since this is the separator used
// in environment variable names.
type Configuration struct {
// Version is the version which defines the format of the rest of the configuration
Version Version `yaml:"version"`
@ -305,6 +308,8 @@ type Storage map[string]Parameters
// Type returns the storage driver type, such as filesystem or s3
func (storage Storage) Type() string {
var storageType []string
// Return only key in this map
for k := range storage {
switch k {
@ -317,9 +322,15 @@ func (storage Storage) Type() string {
case "redirect":
// allow configuration of redirect
default:
return k
storageType = append(storageType, k)
}
}
if len(storageType) > 1 {
panic("multiple storage drivers specified in configuration or environment: " + strings.Join(storageType, ", "))
}
if len(storageType) == 1 {
return storageType[0]
}
return ""
}

140
configuration/configuration_test.go
View file

@ -4,6 +4,8 @@ import (
"bytes"
"net/http"
"os"
"reflect"
"strings"
"testing"
. "gopkg.in/check.v1"
@ -203,6 +205,8 @@ func (suite *ConfigSuite) TestParseIncomplete(c *C) {
suite.expectedConfig.Notifications = Notifications{}
suite.expectedConfig.HTTP.Headers = nil
// Note: this also tests that REGISTRY_STORAGE and
// REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY can be used together
os.Setenv("REGISTRY_STORAGE", "filesystem")
os.Setenv("REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY", "/tmp/testroot")
os.Setenv("REGISTRY_AUTH", "silly")
@ -256,17 +260,6 @@ func (suite *ConfigSuite) TestParseWithDifferentEnvStorageType(c *C) {
c.Assert(config, DeepEquals, suite.expectedConfig)
}
// TestParseWithExtraneousEnvStorageParams validates that environment variables
// that change parameters out of the scope of the specified storage type are
// ignored.
func (suite *ConfigSuite) TestParseWithExtraneousEnvStorageParams(c *C) {
os.Setenv("REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY", "/tmp/testroot")
config, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
c.Assert(err, IsNil)
c.Assert(config, DeepEquals, suite.expectedConfig)
}
// TestParseWithDifferentEnvStorageTypeAndParams validates that providing an environment variable
// that changes the storage type will be reflected in the parsed Configuration struct and that
// environment storage parameters will also be included
@ -346,6 +339,131 @@ func (suite *ConfigSuite) TestParseInvalidVersion(c *C) {
c.Assert(err, NotNil)
}
// TestParseExtraneousVars validates that environment variables referring to
// nonexistent variables don't cause side effects.
func (suite *ConfigSuite) TestParseExtraneousVars(c *C) {
suite.expectedConfig.Reporting.Bugsnag.Endpoint = "localhost:8080"
// A valid environment variable
os.Setenv("REGISTRY_REPORTING_BUGSNAG_ENDPOINT", "localhost:8080")
// Environment variables which shouldn't set config items
os.Setenv("registry_REPORTING_NEWRELIC_LICENSEKEY", "NewRelicLicenseKey")
os.Setenv("REPORTING_NEWRELIC_NAME", "some NewRelic NAME")
os.Setenv("REGISTRY_DUCKS", "quack")
os.Setenv("REGISTRY_REPORTING_ASDF", "ghjk")
config, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
c.Assert(err, IsNil)
c.Assert(config, DeepEquals, suite.expectedConfig)
}
// TestParseEnvVarImplicitMaps validates that environment variables can set
// values in maps that don't already exist.
func (suite *ConfigSuite) TestParseEnvVarImplicitMaps(c *C) {
readonly := make(map[string]interface{})
readonly["enabled"] = true
maintenance := make(map[string]interface{})
maintenance["readonly"] = readonly
suite.expectedConfig.Storage["maintenance"] = maintenance
os.Setenv("REGISTRY_STORAGE_MAINTENANCE_READONLY_ENABLED", "true")
config, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
c.Assert(err, IsNil)
c.Assert(config, DeepEquals, suite.expectedConfig)
}
// TestParseEnvWrongTypeMap validates that incorrectly attempting to unmarshal a
// string over existing map fails.
func (suite *ConfigSuite) TestParseEnvWrongTypeMap(c *C) {
os.Setenv("REGISTRY_STORAGE_S3", "somestring")
_, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
c.Assert(err, NotNil)
}
// TestParseEnvWrongTypeStruct validates that incorrectly attempting to
// unmarshal a string into a struct fails.
func (suite *ConfigSuite) TestParseEnvWrongTypeStruct(c *C) {
os.Setenv("REGISTRY_STORAGE_LOG", "somestring")
_, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
c.Assert(err, NotNil)
}
// TestParseEnvWrongTypeSlice validates that incorrectly attempting to
// unmarshal a string into a slice fails.
func (suite *ConfigSuite) TestParseEnvWrongTypeSlice(c *C) {
os.Setenv("REGISTRY_LOG_HOOKS", "somestring")
_, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
c.Assert(err, NotNil)
}
// TestParseEnvMany tests several environment variable overrides.
// The result is not checked - the goal of this test is to detect panics
// from misuse of reflection.
func (suite *ConfigSuite) TestParseEnvMany(c *C) {
os.Setenv("REGISTRY_VERSION", "0.1")
os.Setenv("REGISTRY_LOG_LEVEL", "debug")
os.Setenv("REGISTRY_LOG_FORMATTER", "json")
os.Setenv("REGISTRY_LOG_HOOKS", "json")
os.Setenv("REGISTRY_LOG_FIELDS", "abc: xyz")
os.Setenv("REGISTRY_LOG_HOOKS", "- type: asdf")
os.Setenv("REGISTRY_LOGLEVEL", "debug")
os.Setenv("REGISTRY_STORAGE", "s3")
os.Setenv("REGISTRY_AUTH_PARAMS", "param1: value1")
os.Setenv("REGISTRY_AUTH_PARAMS_VALUE2", "value2")
os.Setenv("REGISTRY_AUTH_PARAMS_VALUE2", "value2")
_, err := Parse(bytes.NewReader([]byte(configYamlV0_1)))
c.Assert(err, IsNil)
}
func checkStructs(c *C, t reflect.Type, structsChecked map[string]struct{}) {
for t.Kind() == reflect.Ptr || t.Kind() == reflect.Map || t.Kind() == reflect.Slice {
t = t.Elem()
}
if t.Kind() != reflect.Struct {
return
}
if _, present := structsChecked[t.String()]; present {
// Already checked this type
return
}
structsChecked[t.String()] = struct{}{}
byUpperCase := make(map[string]int)
for i := 0; i < t.NumField(); i++ {
sf := t.Field(i)
// Check that the yaml tag does not contain an _.
yamlTag := sf.Tag.Get("yaml")
if strings.Contains(yamlTag, "_") {
c.Fatalf("yaml field name includes _ character: %s", yamlTag)
}
upper := strings.ToUpper(sf.Name)
if _, present := byUpperCase[upper]; present {
c.Fatalf("field name collision in configuration object: %s", sf.Name)
}
byUpperCase[upper] = i
checkStructs(c, sf.Type, structsChecked)
}
}
// TestValidateConfigStruct makes sure that the config struct has no members
// with yaml tags that would be ambiguous to the environment variable parser.
func (suite *ConfigSuite) TestValidateConfigStruct(c *C) {
structsChecked := make(map[string]struct{})
checkStructs(c, reflect.TypeOf(Configuration{}), structsChecked)
}
func copyConfig(config Configuration) *Configuration {
configCopy := new(Configuration)

212
configuration/parser.go
View file

@ -4,10 +4,11 @@ import (
"fmt"
"os"
"reflect"
"regexp"
"sort"
"strconv"
"strings"
"github.com/Sirupsen/logrus"
"gopkg.in/yaml.v2"
)
@ -59,18 +60,29 @@ type VersionedParseInfo struct {
ConversionFunc func(interface{}) (interface{}, error)
}
type envVar struct {
name string
value string
}
type envVars []envVar
func (a envVars) Len() int { return len(a) }
func (a envVars) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a envVars) Less(i, j int) bool { return a[i].name < a[j].name }
// Parser can be used to parse a configuration file and environment of a defined
// version into a unified output structure
type Parser struct {
prefix string
mapping map[Version]VersionedParseInfo
env map[string]string
env envVars
}
// NewParser returns a *Parser with the given environment prefix which handles
// versioned configurations which match the given parseInfos
func NewParser(prefix string, parseInfos []VersionedParseInfo) *Parser {
p := Parser{prefix: prefix, mapping: make(map[Version]VersionedParseInfo), env: make(map[string]string)}
p := Parser{prefix: prefix, mapping: make(map[Version]VersionedParseInfo)}
for _, parseInfo := range parseInfos {
p.mapping[parseInfo.Version] = parseInfo
@ -78,9 +90,17 @@ func NewParser(prefix string, parseInfos []VersionedParseInfo) *Parser {
for _, env := range os.Environ() {
envParts := strings.SplitN(env, "=", 2)
p.env[envParts[0]] = envParts[1]
p.env = append(p.env, envVar{envParts[0], envParts[1]})
}
// We must sort the environment variables lexically by name so that
// more specific variables are applied before less specific ones
// (i.e. REGISTRY_STORAGE before
// REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY). This sucks, but it's a
// lot simpler and easier to get right than unmarshalling map entries
// into temporaries and merging with the existing entry.
sort.Sort(p.env)
return &p
}
@ -111,9 +131,16 @@ func (p *Parser) Parse(in []byte, v interface{}) error {
return err
}
err = p.overwriteFields(parseAs, p.prefix)
if err != nil {
return err
for _, envVar := range p.env {
pathStr := envVar.name
if strings.HasPrefix(pathStr, strings.ToUpper(p.prefix)+"_") {
path := strings.Split(pathStr, "_")
err = p.overwriteFields(parseAs, pathStr, path[1:], envVar.value)
if err != nil {
return err
}
}
}
c, err := parseInfo.ConversionFunc(parseAs.Interface())
@ -124,80 +151,133 @@ func (p *Parser) Parse(in []byte, v interface{}) error {
return nil
}
func (p *Parser) overwriteFields(v reflect.Value, prefix string) error {
// overwriteFields replaces configuration values with alternate values specified
// through the environment. Precondition: an empty path slice must never be
// passed in.
func (p *Parser) overwriteFields(v reflect.Value, fullpath string, path []string, payload string) error {
for v.Kind() == reflect.Ptr {
if v.IsNil() {
panic("encountered nil pointer while handling environment variable " + fullpath)
}
v = reflect.Indirect(v)
}
switch v.Kind() {
case reflect.Struct:
for i := 0; i < v.NumField(); i++ {
sf := v.Type().Field(i)
fieldPrefix := strings.ToUpper(prefix + "_" + sf.Name)
if e, ok := p.env[fieldPrefix]; ok {
fieldVal := reflect.New(sf.Type)
err := yaml.Unmarshal([]byte(e), fieldVal.Interface())
if err != nil {
return err
}
v.Field(i).Set(reflect.Indirect(fieldVal))
}
err := p.overwriteFields(v.Field(i), fieldPrefix)
if err != nil {
return err
}
}
return p.overwriteStruct(v, fullpath, path, payload)
case reflect.Map:
p.overwriteMap(v, prefix)
return p.overwriteMap(v, fullpath, path, payload)
case reflect.Interface:
if v.NumMethod() == 0 {
if !v.IsNil() {
return p.overwriteFields(v.Elem(), fullpath, path, payload)
}
// Interface was empty; create an implicit map
var template map[string]interface{}
wrappedV := reflect.MakeMap(reflect.TypeOf(template))
v.Set(wrappedV)
return p.overwriteMap(wrappedV, fullpath, path, payload)
}
}
return nil
}
func (p *Parser) overwriteMap(m reflect.Value, prefix string) error {
switch m.Type().Elem().Kind() {
case reflect.Struct:
for _, k := range m.MapKeys() {
err := p.overwriteFields(m.MapIndex(k), strings.ToUpper(fmt.Sprintf("%s_%s", prefix, k)))
if err != nil {
return err
}
}
envMapRegexp, err := regexp.Compile(fmt.Sprintf("^%s_([A-Z0-9]+)$", strings.ToUpper(prefix)))
if err != nil {
return err
}
for key, val := range p.env {
if submatches := envMapRegexp.FindStringSubmatch(key); submatches != nil {
mapValue := reflect.New(m.Type().Elem())
err := yaml.Unmarshal([]byte(val), mapValue.Interface())
if err != nil {
return err
}
m.SetMapIndex(reflect.ValueOf(strings.ToLower(submatches[1])), reflect.Indirect(mapValue))
}
}
case reflect.Map:
for _, k := range m.MapKeys() {
err := p.overwriteMap(m.MapIndex(k), strings.ToUpper(fmt.Sprintf("%s_%s", prefix, k)))
if err != nil {
return err
}
}
default:
envMapRegexp, err := regexp.Compile(fmt.Sprintf("^%s_([A-Z0-9]+)$", strings.ToUpper(prefix)))
if err != nil {
return err
func (p *Parser) overwriteStruct(v reflect.Value, fullpath string, path []string, payload string) error {
// Generate case-insensitive map of struct fields
byUpperCase := make(map[string]int)
for i := 0; i < v.NumField(); i++ {
sf := v.Type().Field(i)
upper := strings.ToUpper(sf.Name)
if _, present := byUpperCase[upper]; present {
panic(fmt.Sprintf("field name collision in configuration object: %s", sf.Name))
}
byUpperCase[upper] = i
}
for key, val := range p.env {
if submatches := envMapRegexp.FindStringSubmatch(key); submatches != nil {
mapValue := reflect.New(m.Type().Elem())
err := yaml.Unmarshal([]byte(val), mapValue.Interface())
if err != nil {
return err
fieldIndex, present := byUpperCase[path[0]]
if !present {
logrus.Warnf("Ignoring unrecognized environment variable %s", fullpath)
return nil
}
field := v.Field(fieldIndex)
sf := v.Type().Field(fieldIndex)
if len(path) == 1 {
// Env var specifies this field directly
fieldVal := reflect.New(sf.Type)
err := yaml.Unmarshal([]byte(payload), fieldVal.Interface())
if err != nil {
return err
}
field.Set(reflect.Indirect(fieldVal))
return nil
}
// If the field is nil, must create an object
switch sf.Type.Kind() {
case reflect.Map:
if field.IsNil() {
field.Set(reflect.MakeMap(sf.Type))
}
case reflect.Ptr:
if field.IsNil() {
field.Set(reflect.New(sf.Type))
}
}
err := p.overwriteFields(field, fullpath, path[1:], payload)
if err != nil {
return err
}
return nil
}
func (p *Parser) overwriteMap(m reflect.Value, fullpath string, path []string, payload string) error {
if m.Type().Key().Kind() != reflect.String {
// non-string keys unsupported
logrus.Warnf("Ignoring environment variable %s involving map with non-string keys", fullpath)
return nil
}
if len(path) > 1 {
// If a matching key exists, get its value and continue the
// overwriting process.
for _, k := range m.MapKeys() {
if strings.ToUpper(k.String()) == path[0] {
mapValue := m.MapIndex(k)
// If the existing value is nil, we want to
// recreate it instead of using this value.
if (mapValue.Kind() == reflect.Ptr ||
mapValue.Kind() == reflect.Interface ||
mapValue.Kind() == reflect.Map) &&
mapValue.IsNil() {
break
}
m.SetMapIndex(reflect.ValueOf(strings.ToLower(submatches[1])), reflect.Indirect(mapValue))
return p.overwriteFields(mapValue, fullpath, path[1:], payload)
}
}
}
// (Re)create this key
var mapValue reflect.Value
if m.Type().Elem().Kind() == reflect.Map {
mapValue = reflect.MakeMap(m.Type().Elem())
} else {
mapValue = reflect.New(m.Type().Elem())
}
if len(path) > 1 {
err := p.overwriteFields(mapValue, fullpath, path[1:], payload)
if err != nil {
return err
}
} else {
err := yaml.Unmarshal([]byte(payload), mapValue.Interface())
if err != nil {
return err
}
}
m.SetMapIndex(reflect.ValueOf(strings.ToLower(path[0])), reflect.Indirect(mapValue))
return nil
}

6
docs/configuration.md
View file

@ -33,12 +33,6 @@ To override this value, set an environment variable like this:
This variable overrides the `/var/lib/registry` value to the `/somewhere`
directory.
>**Note**: If an environment variable changes a map value into a string, such
>as replacing the storage driver type with `REGISTRY_STORAGE=filesystem`, then
>all sub-fields will be erased. As such, specifying the storage type in the
>environment will remove all parameters related to the old storage
>configuration (order *matters*).
## Overriding the entire configuration file
If the default configuration is not a sound basis for your usage, or if you are having issues overriding keys from the environment, you can specify an alternate YAML configuration file by mounting it as a volume in the container.