How to cache maven dependencies in Docker

Question

I\'m working on a project with ~200MB dependencies and i\'d like to avoid useless uploads due to my limited bandwidth.

When I push my Dockerfile (i\'ll attach it in a m

Answer 1

In general Dockerfile container build, works in layers and each time you build these layers are available in catch and is used if there are no changes. Ideally it should have worked same way.

Maven generally looks for dependencies by default in .m2 folder located in Home dir of User in Ubuntu /home/username/

If dependent jars are not available then it downloads those jars to .m2 and uses it.

Now you can zip and copy this .m2 folder after 1 successful build and move it inside Docker Container User's Home directory.

Do this before you run build command

Note: You might need to replace existing .m2 folder in docker

So your Docker file would be something like this

FROM maven:3.6.0-jdk-8-slim

WORKDIR /app

COPY .m2.zip /home/testuser/

ADD pom.xml /app

RUN mvn verify clean --fail-never

COPY ./src /app/src

RUN mvn package
...