Merge pull request #103 from pinguo/ft_iter41_merge-mongodb

add pipone

adapter/interface.go

@@ -224,6 +224,7 @@ type IMongodb interface {
 	DeleteOne(query interface{}) error
 	InsertAll(docs interface{}) error
 	PipeAll(query interface{}, desc interface{}) error
+	PipeOne(pipeline interface{}, result interface{}) error
 	UpdateOrInsert(query interface{}, doc interface{}) error
 	FindOne(query interface{}, doc interface{}, options ...bson.M) error
 	FindAll(query interface{}, doc interface{}, options ...bson.M) error

adapter/mongodb.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/globalsign/mgo"
 	"github.com/globalsign/mgo/bson"
 	"github.com/qiniu/qmgo"
 	"go.mongodb.org/mongo-driver/mongo"
@@ -291,6 +292,29 @@ func (m *Mongodb) UpdateOrInsert(query interface{}, doc interface{}) error {
 	return err
 }
 
+// PipeOne execute aggregation queries and get the first item from result set.
+// param pipeline must be a slice, such as []bson.M,
+// param result is a pointer to interface{}, map, bson.M or bson compatible struct.
+// for example:
+//
+//	pipeline := []bson.M{
+//	    bson.M{"$match": bson.M{"status":"A"}},
+//	    bson.M{"$group": bson.M{"_id":"$field1", "total":"$field2"}},
+//	}
+//	m.PipeOne(pipeline, &result)
+func (m *Mongodb) PipeOne(pipeline interface{}, result interface{}) error {
+	profile := "Mongo.PipeOne"
+	m.Context().ProfileStart(profile)
+	defer m.Context().ProfileStop(profile)
+	col := m.client.MClient.Database(m.db).Collection(m.coll)
+	e := col.Aggregate(context.Background(), pipeline).One(result)
+	if e != nil && e != mgo.ErrNotFound {
+		m.Context().Error(profile + " error, " + e.Error())
+	}
+
+	return e
+}
+
 func (m *Mongodb) PipeAll(query interface{}, doc interface{}) error {
 	profile := "mongodb.PipeAll"
 	m.Context().ProfileStart(profile)