Need help with mongoDB go driver

[Sahil_Chawla]

Hi All,

I am using official mongoDB go driver in my code and it was working fine until I decided to use docker-compose to spin up my mongodb and go-app container.

My code builds fine but I am getting below error whenever I try to access home page of my go web-app.

Error:

app        | 2020/07/14 13:19:00 server selection error: server selection timeout, current topology: { Type: Unknown, Servers: [{ Addr: localhost:27017, Type: Unknown, State: Connected, Average RTT: 0, Last error: connection() : dial tcp 127.0.0.1:27017: connect: connection refused }, ] }

Docker-Compose File:

version: '3.1'

services:

  mongodb:
    image: mongo
    container_name: mongodb
    restart: always
    ports:
          - 27017:27017
    environment:
      MONGO_INITDB_ROOT_USERNAME: root
      MONGO_INITDB_ROOT_PASSWORD: local
    command: mongod --bind_ip mongodb


  app:
    image: app:1.4
    container_name: app
    environment:
      - MONGO_URL=mongodb
    ports:
         - 80:8080
    depends_on:
      - mongodb
    restart: always

Running Docker Containers

docker ps
CONTAINER ID        IMAGE                COMMAND                  CREATED             STATUS              PORTS                      NAMES
d130336be71e        app:1.4   "/app/main"              4 minutes ago       Up 2 seconds        0.0.0.0:80->8080/tcp       app
dc57dd2de645        mongo                "docker-entrypoint.s…"   4 minutes ago       Up 2 seconds        0.0.0.0:27017->27017/tcp   mongodb

Go-Function

func GetSession() (*mongo.Client, error) {
	dbURL := os.Getenv("MONGO_URL")
	
	// Set client options
	clientOptions := options.Client()
	clientOptions.SetDirect(true).ApplyURI("mongodb://" + dbUser + ":" + dbPassword + "@" + dbURL +":27017/?connect=direct")

	// Connect to MongoDB
	client, err := mongo.Connect(context.TODO(), clientOptions)

	if err != nil {
		Logger(Fatal, err)
	}

	// Check the connection
	err = client.Ping(context.TODO(), nil)

	if err != nil {
		Logger(Fatal, err)
	}
	// Return successful connection
	return client, nil

}

Troubleshooting

1. As part of trying to figure out what is wrong I looked at similar issues highlighted in stackoverflow and tried below options:

• Tried to use connect=direct in connection URI
• Tried to use SetDirect
• Added --bindip as highlighted in my docker-compose file

2. I logged-in into the app container and tried to ping mongodb and it worked:

root@d130336be71e:/app# ping mongodb
PING mongodb (172.18.0.2) 56(84) bytes of data.
64 bytes from mongodb.app_default (172.18.0.2): icmp_seq=1 ttl=64 time=0.159 ms
64 bytes from mongodb.app_default (172.18.0.2): icmp_seq=2 ttl=64 time=0.200 ms
64 bytes from mongodb.app_default (172.18.0.2): icmp_seq=3 ttl=64 time=0.079 ms
64 bytes from mongodb.app_default (172.18.0.2): icmp_seq=4 ttl=64 time=0.087 ms
64 bytes from mongodb.app_default (172.18.0.2): icmp_seq=5 ttl=64 time=0.083 ms
^C
--- mongodb ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 60ms
rtt min/avg/max/mdev = 0.079/0.121/0.200/0.050 ms