[Bug]: Data Race accessing reaper instance for docker containers

[davidsbond]

Testcontainers version

0.24.1

Using the latest Testcontainers version?

Yes

Host OS

Linux

Host arch

amd64

Go version

1.21

Docker version

24.0.6

Docker info

This is running in github actions so I don't have access to it.

What happened?

When using testcontainers with the -race flag enabled, a race is detected within the testcontainers package. It seems to be due to some code paths not using the reaperMux when accessing the session identifiers. For example here:

https://github.com/testcontainers/testcontainers-go/blob/main/docker.go#L881

Relevant log output

WARNING: DATA RACE
Write at 0x000001a3cc50 by goroutine 17:
  github.com/testcontainers/testcontainers-go.reuseOrCreateReaper()
      /home/runner/go/pkg/mod/github.com/testcontainers/[email protected]/reaper.go:155 +0x624

Previous read at 0x000001a3cc50 by goroutine 14:
  github.com/testcontainers/testcontainers-go.(*DockerProvider).CreateContainer()
      /home/runner/go/pkg/mod/github.com/testcontainers/[email protected]/docker.go:881 +0xb34

Additional information

No response

[mdelapenya]

Oh, you are totally right! I introduced the race condition checking if the reaperInstance is nil 🤦

I'll work on a fix ASAP. Thanks for reporting this.

Just to let you know, we are working on a draft document for an eventual v1 release, in which we'd like to refine all the bootstrapping of the library, in particular how config, reaper and test session is initialised. So it would be fixed at that time in a more proper manner. Nevertheless, I'll tackle this bug now.

[mdelapenya]

I can reproduce the bug with:

go test -timeout 600s -run ^Test_BuildImageWithContexts$ . -race -count=1 -v

I also have a working branch without that error.

[mdelapenya]

A PR fix has been sent, thanks for the report!

[davidsbond]

Thanks for the quick look! Glad to help :)