Goal

The goal is to add a linter for shell files to control quality as we introduce more scripting into the project.

shellcheck

The shellcheck tool is not very complicated to use. Once you get a binary to run, you just point it to a file to run its checks against. I utilized a Docker image and used the recommended find + xargs approach to run it on all the shell files in the project.

Given that the command is a one-liner, I decide to put it in the Makefile directly:

lint:
	docker compose exec app black --check .
	docker compose exec app flake8 .
	docker run --rm -v $(CURDIR):/mnt koalaman/shellcheck-alpine sh -c "find /mnt -name '*.sh' | xargs shellcheck"

Note: Having multiple commands under a Make target is not necessarily a bad thing, but perhaps I should consider moving these into a standalone script if it gets too complicated.

Running make lint would now fail if any of the shell scripts fail the checks. See the lab branch — my existing entrypoint script failed and I had to make changes!

Conclusion

In this lab, I added the linter shellcheck to run checks against shell scripts in the project.

The source is available at the feature/004-shellcheck branch.