forked from xiaonanln/goworld
/
mongodb.go
100 lines (85 loc) · 1.89 KB
/
mongodb.go
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package kvdbmongo
import (
"gopkg.in/mgo.v2"
"io"
"github.com/xiaonanln/goworld/engine/gwlog"
"github.com/xiaonanln/goworld/engine/kvdb/types"
"gopkg.in/mgo.v2/bson"
)
const (
_DEFAULT_DB_NAME = "goworld"
_VAL_KEY = "_"
)
type mongoKVDB struct {
s *mgo.Session
c *mgo.Collection
}
// OpenMongoKVDB opens mongodb as KVDB engine
func OpenMongoKVDB(url string, dbname string, collectionName string) (kvdbtypes.KVDBEngine, error) {
gwlog.Debugf("Connecting MongoDB ...")
session, err := mgo.Dial(url)
if err != nil {
return nil, err
}
session.SetMode(mgo.Monotonic, true)
if dbname == "" {
// if db is not specified, use default
dbname = _DEFAULT_DB_NAME
}
db := session.DB(dbname)
c := db.C(collectionName)
return &mongoKVDB{
s: session,
c: c,
}, nil
}
func (kvdb *mongoKVDB) Put(key string, val string) error {
_, err := kvdb.c.UpsertId(key, map[string]string{
_VAL_KEY: val,
})
return err
}
func (kvdb *mongoKVDB) Get(key string) (val string, err error) {
q := kvdb.c.FindId(key)
var doc map[string]string
err = q.One(&doc)
if err != nil {
if err == mgo.ErrNotFound {
err = nil
}
return
}
val = doc[_VAL_KEY]
return
}
type mongoKVIterator struct {
it *mgo.Iter
}
func (it *mongoKVIterator) Next() (kvdbtypes.KVItem, error) {
var doc map[string]string
ok := it.it.Next(&doc)
if ok {
return kvdbtypes.KVItem{
Key: doc["_id"],
Val: doc["_"],
}, nil
}
err := it.it.Close()
if err != nil {
return kvdbtypes.KVItem{}, err
}
return kvdbtypes.KVItem{}, io.EOF
}
func (kvdb *mongoKVDB) Find(beginKey string, endKey string) (kvdbtypes.Iterator, error) {
q := kvdb.c.Find(bson.M{"_id": bson.M{"$gte": beginKey, "$lt": endKey}})
it := q.Iter()
return &mongoKVIterator{
it: it,
}, nil
}
func (kvdb *mongoKVDB) Close() {
kvdb.s.Close()
}
func (kvdb *mongoKVDB) IsConnectionError(err error) bool {
return err == io.EOF || err == io.ErrUnexpectedEOF
}