Run tests inside Docker container with Jenkins

Question

We want to give it a try to setup CI/CD with Jenkins for our project. The project itself has Elasticsearch and PostgreSQL as runtime dependencies and Webdriver for acceptance testing. In dev environment, everything is set up within one docker-compose.yml file and we have acceptance.sh script to run acceptance tests.

After digging documentation I found that it's potentially possible to build CI with following steps:

1. dockerize project
2. pull project from git repo
3. somehow pull docker-compose.yml and project Dockerfile - either:
   • put it in the project repo
   • put it in separate repo (this is how it's done now)
   • put somewhere on a server and jut copy it over
4. execute docker-compose up
5. project's Dockerfile will have ONBUILT section to run tests. Unit tests are run through mix tests and acceptance through scripts/acceptance.sh. It'll be cool to run them in parallel.
6. shutdown docker-compose, clean up containers

Because this is my first experience with Jenkins a series of questions arise:

• Is this a viable strategy?
• How to connect tests output with Jenkins?
• How to run and shut down docker-compose?
• Do we need/want to write a pipeline for that? Will we need/want pipeline when we will get to the CD on the next stage?

Thanks

Answer 1

Is this a viable strategy?

Yes it is. I think it would be better to include the docker-compose.yml and Dockerfile in the project repo. That way any changes are tied to the version of code that uses the changes. If it's in an external repo it becomes a lot harder to change (unless you pin the git sha somehow , like using a submodule).

project's Dockerfile will have ONBUILD section to run tests

I would avoid this. Just set a different command to run the tests in a container, not at build time.

How to connect tests output with Jenkins?

Jenkins just uses the exit status from the build steps, so as long as the test script exits with a non-zero code on failure and a zero code on success that's all you need. Test output that is printed to stdout/stderr will be visible from jenkins console.

How to run and shut down docker-compose?

I would recommend this to run Compose:

docker-compose pull # if you use images from the hub, pull the latest version
docker-compose up --build -d

In a post-build step to shutdown:

docker-compose down --volumes

Do we need/want to write a pipeline for that?

No, I think just a single job is fine. Get it working with a simple setup first, and then you can figure out what you need to split into different jobs.