docker - Dockerignore: Ignore everything except a file and the Dockerfile

Question

So the main intention was to dockerize a fat jar application and put it into Elasticbeanstalk. The problem is with the context. It's a little bit stupid to add so much context into docker if all I need is actually a single jar file.

I've been playing around with the .dockerignore file, but I am lost. I tried to use the gitignore negation, but it doesn't work.

*
!Dockerfile
*/
!target/
target/*
!target/*.jar

There's also that thing with regex, but it seems like complicated regex is not supported.

^((?!Dockerfile).)*$

I have also tried searching in stackoverflow, and these two are all I found:

• Exceptions in .dockerignore

• is there a way to negate a pattern in .dockerignore?

This question might be similiar to the second one, but I think it's slightly difference since in here, I just want to include a single file into the context.

Any help will be appreciated.

Answer 1

If you need to ignore everything except some directories or files and also ignore some unnecessary files inside those allowed directories you can use the following .dockerignore file:

# Ignore everything
**

# Allow files and directories
!/file.txt
!/src/**

# Ignore unnecessary files inside allowed directories
# This should go after the allowed directories
**/*~
**/*.log
**/.DS_Store
**/Thumbs.db