A very simple docker compose configuration for development with Node.js, MongoDB, and Redis. This configuration is ment to provide an isolated development enviroment.
My intention with this configuration is not only to use it by myself, but also share with students who might not have use Docker before. Becuase if this I tried to make the instructions as detailed as possible. If you feel anything is missing or have any questions, please create an issue or a pull request.
To use this configuration you will need to install Docker Engine to run the Docker containers. You will also need to install Docker Compose since this configuration uses three containers. If you have never used Docker before I would recommend you look at Get started with Docker.
- Create a project folder
- Pull the repository into your project folder
- Create your entry point file for your javascript program, example
app.js. If you want to you can create ansrc/folder and place it in there if you want to. - Create an empty file called
package.json. We will use npm init later but if the file does not exist the build of the docker image will fail. - Open the
Dockerfilein a text editor and edit the lineENV APP_MAIN app.js. Changeapp.jsto whereever you placed your entry point file. Remember that this is relative to the root of your project folder. - Open a terminal and navigate to your project folder
- Build the images and start the containers with
docker-compose up
- Pull the repository into your project folder.
- If it's not there already, move you
package.jsonto the root of your project. - Open the
Dockerfilein a text editor and edit the lineENV APP_MAIN app.js. Changeapp.jsto where your entry point file is relative to the root of the project folder - Open a terminal and navigate to your project folder
- Build the images and start the containers with
docker-compose up
This container uses a npm module called nodemon which detect changes in your project files and rebuilds the project for you, so your application will run every time you make a change.
If you need to install an npm module you can use the run command to send commands to your container. To install the npm module for express on your app container just run docker-compose run app npm install express --save.
The configuration devides the application, database, and cache into three containers, so how do they communicate? In this configuration I've created a link from the application container to both the database and cache containers. This makes it possible to communicate with these containers from the application kind of like a network.
This division also means that we can't use localhost:27017 to communicate with the database. The other containers have instead been given a hostname in the application container. To access the MongoDB database instead of localhost:27017 use mongo:27017, and for Redis container redis:6379.
The only container accessible from the host machine is the application container which exposes the 8080 port to the host machine. This port is mapped 8080:8080 so to make your application accessible it should listen on port 8080.
The database and cache container can not be accessible from the host machine (excluding using docker tools). All communications with these containers are done though the application container.
- app
- mongo
- redis
The signed in user on the local machine will not have write access to files created by the containers, so you might need to use sudo every now and again. If anyone has a fix for this, please share.
Here are a couple of good to know commands to know. If something goes wrong with your containers these command together will more or less return you to the state before running docker-compose up.
# Stops all containers running on your machine
$ docker stop $(docker ps -a -q)
# Removes all containers on your machine
$ docker rm $(docker ps -a -q)
# Removes all images on your machine
$ docker rmi $(docker images -q)