Docker Compose is a tool that allows you to run multi-container applications. With compose we can use yaml files to configure our application’ services and then using a single command create and start all of the configured services. I use this tool a lot when it comes to local development in a microservice environment. It is also lightweight and needs just a small effort. Instead of managing how to run each service while developing you can have the environment and services needed preconfigured and focus on the service that you currently develop.
With docker compose we can configure a network for our services, volumes, mount-points, environmental variables just about everything.
To showcase this we are going to solve a problem. Our goal would be to extract data from mongodb using grafana. Grafana does not have out of the box support for MongoDB therefore we will have to use a plugin.
First step we shall create our networks. Creating a network is not necessary since your services once started will join the default network. We shall make a showcase of using custom networks. We shall have a network for backend services and a network for frontend services. Apparently network configuration can get more advanced and specify custom network drivers or even configure static addresses.
1 2 3 4 5 6 7 8 | version: '3.5'networks: frontend: name: frontend-network backend: name: backend-network internal: true |
The backend network is going to be internal therefore there won’t be any outbound connectivity to the containers attached to it.
Then we shall setup our mongodb instance.
01 02 03 04 05 06 07 08 09 10 11 12 13 | version: '3.5'services: mongo: image: mongo restart: always environment: MONGO_INITDB_ROOT_USERNAME: ${MONGO_USER} MONGO_INITDB_ROOT_PASSWORD: ${MONGO_PASSWORD} volumes: - ${DB_PATH}:/data/db networks: - backend |
As you see we specified a volume. Volumes can also be specified separately and attach them to a service.
Also we used environmental variables for the root account, you might as well have spotted that the password is going to be provided through environmental variables ie. MONGO_USER=root MONGO_PASSWORD=root docker-compose -f stack.yaml up. The same applies for the volume path too. You can have a more advanced configuration for volumes in your compose configuration and reference them from your service.
Our next goal is to setup the proxy server which shall be in the middle of our grafana and mongodb server. Since it needs a custom Dockerfile to create it, we shall do it through docker-compose. Compose has the capability to spin up a service by specifying the docker file.
So let’s start with the Dockerfile.
01 02 03 04 05 06 07 08 09 10 11 | FROM nodeWORKDIR /usr/src/mongografanaproxyCOPY . /usr/src/mongografanaproxyEXPOSE 3333RUN cd /usr/src/mongografanaproxyRUN npm installENTRYPOINT ["npm","run","server"] |
Then let’s add it to compose
01 02 03 04 05 06 07 08 09 10 | version: '3.5'services: mongo-proxy: build: context: . dockerfile: ProxyDockerfile restart: always networks: - backend |
And the same shall be done to the Grafana image that we want to use. In stead of using a ready grafana image we shall create one with the plugin preinstalled.
1 2 3 4 5 | FROM grafana/grafanaCOPY . /var/lib/grafana/plugins/mongodb-grafanaEXPOSE 3000 |
01 02 03 04 05 06 07 08 09 10 11 12 13 | version: '3.5'services: grafana: build: context: . dockerfile: GrafanaDockerfile restart: always ports: - 3000:3000 networks: - backend - frontend |
Let’s wrap them all together
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | version: '3.5'services: mongo: image: mongo restart: always environment: MONGO_INITDB_ROOT_USERNAME: ${MONGO_USER} MONGO_INITDB_ROOT_PASSWORD: ${MONGO_PASSWORD} volumes: - ${DB_PATH}:/data/db networks: - backend mongo-proxy: build: context: . dockerfile: ProxyDockerfile restart: always networks: - backend grafana: build: context: . dockerfile: GrafanaDockerfile restart: always ports: - 3000:3000 networks: - backend - frontendnetworks: frontend: name: frontend-network backend: name: backend-network internal: true |
So let’s run them all together.
1 2 | docker-compose -f stack.yaml buildMONGO_USER=root MONGO_PASSWORD=root DB_PATH=~/grafana-mongo docker-compose -f stack.yaml up |
The above can be found on github.
You might as well find the Docker Images, Docker Containers and Docker registry posts useful.
Published on Web Code Geeks with permission by Emmanouil Gkatziouras, partner at our WCG program. See the original article here: Docker basics: Docker compose Opinions expressed by Web Code Geeks contributors are their own. |
