Multi tool use

Converting docker-compose file to bash to auto run tests

I'm currently working on an app and I want to auto test express before i push my code to production.

I have a docker-compose file which I can use to run my tests

version: '8'
services:
express:
build: services/comp/express
ports:
- "3000:3000"
database:
image: mongo:3.4.0
ports:
- "27017:27017"


However I want to be able to run these through a bash script instead (I don't want two docker-compose files).

I've tried the command

docker run -d -p 27017:27017 mongo:3.4.0


to run my database and to run my express server i've tried

docker build -t express_image ./comp/services/express/.
docker run -p 3000:3000 -t express_image


However, I can't get my tests running like this. I'm getting a cannot connect to database on first try error so I presume I'm using the wrong host for my database. When using a docker-compose file, I tried
const dbHost = 'mongodb://database/test-db';
to connect to the data base which works. While trying to run with the above commands, I've tried

const dbHost = 'mongodb://database/test-db';

const dbHost = 'mongodb://localhost:27017/';


Any advice on what I'm doing wrong to spin up the two containers through a terminal?

2 Answers
2

What i understand from above.. while using single docker-compose to auto test experess you have used const dbHost ='mongodb://database/test-db' and it worked fine.

const dbHost ='mongodb://database/test-db'

Now you have spin the container without docker-compose and trying to access db from express container using const dbHost = 'mongodb://localhost:27017/';

const dbHost = 'mongodb://localhost:27017/';

Reason for not working.. here local host is your express container not your Docker host machine where you have mapped mongodb container port.

Replace with -> const dbHost = 'mongodb://${docker_host_ip}:27017/';

const dbHost = 'mongodb://${docker_host_ip}:27017/';

Docker_host_ip will be the ip of docker_bridge for networking. Like 172.16.0.1(for Docker host machine).

You need to do a couple of things to cause Docker to create and use an internal network, so its internal DNS resolution works. Docker Compose does this automatically for you, but if you're running Docker commands by hand you need to do it manually.

First, create the network, with totally default options:

docker network create mean


Then when you run the containers, attach them to this network, and explicitly give them names:

docker run -d --net mean --name database -p 27017:27017 mongo:3.6.2
docker build -t expressapp ./services/express
docker run -d --net mean --name express -p 3000:3000 expressapp


If the database location is in a constant in code as you've illustrated, you'll find this inflexible if you ever change the database location. You might set it from an environment variable, using process.env in your Node code and the docker run -e option to set the actual location when you run the container.

process.env

docker run -e

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