1 files changed, 145 insertions, 0 deletions
diff --git a/src/tools/emcoui/middle_end/db/dbconnection.go b/src/tools/emcoui/middle_end/db/dbconnection.go
new file mode 100644
index 00000000..5496c39c
--- /dev/null
+++ b/src/tools/emcoui/middle_end/db/dbconnection.go
@@ -0,0 +1,145 @@
+/*
+=======================================================================
+Copyright (c) 2017-2020 Aarna Networks, Inc.
+All rights reserved.
+======================================================================
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+          http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+========================================================================
+*/
+
+package db
+
+import (
+	"encoding/json"
+	"fmt"
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/mongo"
+	"go.mongodb.org/mongo-driver/mongo/options"
+	"golang.org/x/net/context"
+)
+
+// MongoStore is the interface which implements the db.Store interface
+type MongoStore struct {
+	db *mongo.Database
+}
+
+// Key interface
+type Key interface {
+}
+
+// DBconn variable of type Store
+var DBconn Store
+
+// Store Interface which implements the data store functions
+type Store interface {
+	HealthCheck() error
+	Find(coll string, key []byte, tag string) ([][]byte, error)
+	Unmarshal(inp []byte, out interface{}) error
+}
+
+// NewMongoStore Return mongo client
+func NewMongoStore(name string, store *mongo.Database, svcEp string) (Store, error) {
+	if store == nil {
+		ip := "mongodb://" + svcEp
+		clientOptions := options.Client()
+		clientOptions.ApplyURI(ip)
+		mongoClient, err := mongo.NewClient(clientOptions)
+		if err != nil {
+			return nil, err
+		}
+
+		err = mongoClient.Connect(context.Background())
+		if err != nil {
+			return nil, err
+		}
+		store = mongoClient.Database(name)
+	}
+	return &MongoStore{
+		db: store,
+	}, nil
+}
+
+// CreateDBClient creates the DB client. currently only mongo
+func CreateDBClient(dbType string, dbName string, svcEp string) error {
+	var err error
+	switch dbType {
+	case "mongo":
+		DBconn, err = NewMongoStore(dbName, nil, svcEp)
+	default:
+		fmt.Println(dbType + "DB not supported")
+	}
+	return err
+}
+
+// HealthCheck verifies the database connection
+func (m *MongoStore) HealthCheck() error {
+	_, err := (*mongo.SingleResult).DecodeBytes(m.db.RunCommand(context.Background(), bson.D{{"serverStatus", 1}}))
+	if err != nil {
+		fmt.Println("Error getting DB server status: err %s", err)
+	}
+	return nil
+}
+
+func (m *MongoStore) Unmarshal(inp []byte, out interface{}) error {
+	err := bson.Unmarshal(inp, out)
+	if err != nil {
+		fmt.Printf("Failed to unmarshall bson")
+		return err
+	}
+	return nil
+}
+
+// Find a document
+func (m *MongoStore) Find(coll string, key []byte, tag string) ([][]byte, error) {
+	var bsonMap bson.M
+	err := json.Unmarshal([]byte(key), &bsonMap)
+	if err != nil {
+		fmt.Println("Failed to unmarshall %s\n", key)
+		return nil, err
+	}
+
+	filter := bson.M{
+		"$and": []bson.M{bsonMap},
+	}
+
+	fmt.Printf("%+v %s\n", filter, tag)
+	projection := bson.D{
+		{tag, 1},
+		{"_id", 0},
+	}
+
+	c := m.db.Collection(coll)
+
+	cursor, err := c.Find(context.Background(), filter, options.Find().SetProjection(projection))
+	if err != nil {
+		fmt.Println("Failed to find the document %s\n", err)
+		return nil, err
+	}
+
+	defer cursor.Close(context.Background())
+	var data []byte
+	var result [][]byte
+	for cursor.Next(context.Background()) {
+		d := cursor.Current
+		switch d.Lookup(tag).Type {
+		case bson.TypeString:
+			data = []byte(d.Lookup(tag).StringValue())
+		default:
+			r, err := d.LookupErr(tag)
+			if err != nil {
+				fmt.Println("Unable to read data %s %s\n", string(r.Value), err)
+			}
+			data = r.Value
+		}
+		result = append(result, data)
+	}
+	return result, nil
+}