*: fixes to be working on new abstractions

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

dbutil/dbutil.go

@@ -7,11 +7,11 @@ import (
 )
 
 // Handles are all the register backing Handlers
-var Handles map[string]Handler
+var Handles = map[string]Handler{}
 
 // Handler is the means of getting "files" from the backing database
 type Handler interface {
-	Init(config interface{}) error
+	Init(config []byte, err error) error
 	Close() error
 
 	Open(filename string) (File, error)
@@ -33,14 +33,38 @@ type Handler interface {
 	GetKeywords() (kp []types.IdCount, err error)
 }
 
-type MetaDataer interface {
-	GetMeta(result interface{}) (err error)
-	SetMeta(metadata interface{})
-}
-
+// File is what is stored and fetched from the backing database
 type File interface {
 	io.Reader
 	io.Writer
 	io.Closer
 	MetaDataer
 }
+
+// MetaDataer allows set/get for optional metadata
+type MetaDataer interface {
+	/*
+		GetMeta unmarshals the optional "metadata" field associated with the file into
+		the result parameter. The meaning of keys under that field is user-defined. For
+		example:
+
+			result := struct{ INode int }{}
+			err = file.GetMeta(&result)
+			if err != nil {
+				panic(err.String())
+			}
+			fmt.Printf("inode: %d\n", result.INode)
+	*/
+	GetMeta(result interface{}) (err error)
+	/*
+		SetMeta changes the optional "metadata" field associated with the file.  The
+		meaning of keys under that field is user-defined. For example:
+
+			file.SetMeta(bson.M{"inode": inode})
+
+		It is a runtime error to call this function when the file is not open for
+		writing.
+
+	*/
+	SetMeta(metadata interface{})
+}

dbutil/mongo/handle.go

@@ -1,6 +1,7 @@
 package mongo
 
 import (
+	"encoding/json"
 	"strings"
 
 	"github.com/vbatts/imgsrv/dbutil"
@@ -29,8 +30,15 @@ type mongoHandle struct {
 	Gfs     *mgo.GridFS
 }
 
-func (h *mongoHandle) Init(config interface{}) (err error) {
-	h.config = config.(dbConfig)
+func (h *mongoHandle) Init(config []byte, err error) error {
+	if err != nil {
+		return err
+	}
+
+	h.config = dbConfig{}
+	if err := json.Unmarshal(config, &h.config); err != nil {
+		return err
+	}
 
 	h.Session, err = mgo.Dial(h.config.Seed)
 	if err != nil {

server.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
 	"log"
@@ -45,7 +46,7 @@ func runServer(c *config.Config) {
 		serverConfig.MongoDbName,
 	}
 
-	if err := du.Init(duConfig); err != nil {
+	if err := du.Init(json.Marshal(duConfig)); err != nil {
 		log.Fatal(err)
 	}
 	defer du.Close() // TODO this ought to catch a signal to cleanup