This is a simple Node.js webapp example running on a Docker container. It demonstrates how an application can be containerized in a way where all dependencies can be defined in a Dockerfile to build an image and deployed in any Docker-ready environment.
For this example, I'm using the following parameters, enclosed by <>
- username: cesschneider
- repository-uri: docker.io/cesschneider
- image-name: hello-docker-world
- tag: latest
Run the following command to build the Docker image. The -t flag lets you tag your image so it's easier to find later using the "docker images" command:
$ docker build -t <repository-uri>/<image-name>:<tag> .
$ docker images
Running your image with -d runs the container in detached mode, leaving the container running in the background. The -p flag redirects a public port to a private port inside the container. Run the image you previously built:
$ docker run -p 8080:8080 -d <repository-uri>/<image-name>
To take a look at the output of your application, run:
$ docker ps
$ docker logs <container-id>
If you need to go inside the container you can use the exec command:
$ docker exec -it <container-id> /bin/bash
To test your app, get the port of your app that Docker mapped:
$ docker ps
ID IMAGE COMMAND ... PORTS
ecce33b30ebf <repository-uri>/<image-name>:<tag> npm start ... 8080->8080
Now you can call your app using curl:
$ curl -i localhost:8080
HTTP/1.1 200 OK
X-Powered-By: Express
Content-Type: text/html; charset=utf-8
Content-Length: 32
ETag: W/"20-RRi36hKIlsw/cMtmbawLT/P+nKE"
Date: Sun, 03 Mar 2019 02:28:19 GMT
Connection: keep-alive
Hello, Node.js on Docker world!
Before you upload new image to Docker Hub repository, you should tag it with an identifier to pull it properly later at your production environment.
$ docker tag <image-name>:<tag> <repository-uri>/<image-name>:<tag>
Once your application is tested and ready for deployment, you can upload it to your DockerHub account and make it available to install it anywhere.
$ docker push <repository-uri>/<image-name>:<tag>
With this command you can pull (download) an image from repository (in this example, DockerHub) and run a container with it, as explained before. You also can push/pull images to Amazon ECR or a private repository.
$ docker pull <repository-uri>/<image-name>:<tag>
$ docker run -p 8080:8080 -d <repository-uri>/<image-name>:<tag>
$ docker ps
I hope this tutorial helped you get up and running a simple Node.js application on Docker.
You can find more information about Docker and Node.js on Docker in the following places: