Suggestions to improve your Dockerfile

[ramonvanstijn]

Hi,

The Dockerfile can be improved in a couple of areas:

1. Implement the best practice for writing Dockerfiles for running apt-get. The best practice says to always combine RUN apt-get update with apt-get install in the same RUN statement. For the full explanation see https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#run
   For example:

RUN apt-get update && apt-get install -y  \
		wget \
	&& rm -rf /var/lib/apt/lists/*

2. Add node_modules to .dockerignore. If you do the instruction RUN rm -rf ./node_modules; can be removed.
3. Remove the instruction RUN cd /app;, you already used WORKDIR "/app" so you are already in /app
4. Don't use semi-colons at the end of an instruction
5. I wouldn't use COPY . /app, it copies everything in the current directory to /app (except what is in .dockerignore of course). The contents of /app with the current Dockerfile looks like this:

root@fa0fc7257bd6:/app# ls -latr
total 384
drwxr-xr-x   3 root root   4096 Feb 23 07:45 views
drwxr-xr-x   2 root root   4096 Feb 23 07:45 test
drwxr-xr-x   5 root root   4096 Feb 23 07:45 server
drwxr-xr-x   5 root root   4096 Feb 23 07:45 public
-rw-r--r--   1 root root   1135 Feb 23 07:45 package.json
-rw-r--r--   1 root root 266356 Feb 23 07:45 package-lock.json
drwxr-xr-x   4 root root   4096 Feb 23 07:45 multiarch-manifests
-rw-r--r--   1 root root    155 Feb 23 07:45 manifest.yml
-rw-r--r--   1 root root   2752 Feb 23 07:45 idt.js
-rw-r--r--   1 root root    672 Feb 23 07:45 gulpfile.js
drwxr-xr-x   2 root root   4096 Feb 23 07:45 docker-8
drwxr-xr-x   2 root root   4096 Feb 23 07:45 docker-6
-rw-r--r--   1 root root    556 Feb 23 07:45 cli-config.yml
drwxr-xr-x   3 root root   4096 Feb 23 07:45 chart
-rw-r--r--   1 root root   6712 Feb 23 07:45 README.md
-rw-r--r--   1 root root  13317 Feb 23 07:45 NOTICES
-rw-r--r--   1 root root  11351 Feb 23 07:45 LICENSE
-rw-r--r--   1 root root    147 Feb 23 07:45 Jenkinsfile
-rw-r--r--   1 root root    394 Feb 23 07:45 Dockerfile
-rw-r--r--   1 root root    109 Feb 23 07:45 .gitignore
drwxr-xr-x   7 root root   4096 Feb 23 07:45 .git
-rw-r--r--   1 root root      5 Feb 23 07:45 .dockerignore
drwxr-xr-x 133 root root   4096 Feb 23 07:48 node_modules
drwxr-xr-x   1 root root   4096 Feb 23 07:48 .
drwxr-xr-x   1 root root   4096 Feb 23 07:48 ..

In my view a lot of stuff that should not be in the /app directory. Of course you can update .dockerignore but it might be a better idea to create a separate folder for your code and copy that folder and individual files to /app instead.

[a-roberts]

Thanks for the suggestion, @jkingoliver FYI - it'd be useful to incorporate this feedback into our Node.js starters and potentially to update this project with the above pointers.