Document: "Check Linked Containers" config setting

[grrowl]

Please document how config option CHECK_LINKED_CONTAINERS (aka env BUILDKITE_PLUGIN_DOCKER_COMPOSE_CHECK_LINKED_CONTAINERS) should be used, as seen in https://github.com/buildkite-plugins/docker-compose-buildkite-plugin/blob/master/hooks/commands/run.sh#L98

I've tried defining the env var in pipeline.yml (in top-level key env and in steps.command.plugins.docker-compose#v1.8.3.env) but each seemed to have no effect.

[lox]

Hi @grrowl 👋🏻It's really not designed to be used, it's an internal setting for testing. What are you trying to accomplish?

[grrowl]

Specifically we have two containers in our compose — selenium/hub and and selenium/node-chrome — who log to stdout and which we need the output for (to debug selenium, natch)

We're successful uploading log artifacts from containers which write to files in mapped volumes; but I can't find a solution for these selenium-based ones which only write to stdout

[lox]

The "check linked containers" setting is supposed to be the default behaviour, which in the case of a failure should grab the log output from all linked containers and upload the logs as assets.

We've just fixed a bug that stopped this behaviour from running (see #103), which I suspect you might be running into.

Beyond that, we've been talking about ways to show logging from all linked containers in #98.

I'm going to get out a new release in the next few minutes @grrowl, hopefully it should fix the issue for you until we have a good solution to showing log output from multiple containers.

[grrowl]

Glorious, thank you! I'll test imminently and follow up

[grrowl]

Confirmed docker-compose#v1.8.4 fixes the issue. Each composed container's logs are uploaded as artifacts, and the main app's log is output in the Buildkite UI.

Thanks for the excellent and speedy reply @lox!