WithReuse method doesn't work with Localstack module

[Yopadd]

Expected Behaviour
If I use .withReuse with LocalstackContainer then testcontainer reuse the current stopped or running localstack container.

Actual Behaviour
A new container are create for each executions

Steps to Reproduce

const container1 = await new LocalstackContainer('localstack/localstack:4.8')
  .withExposedPorts({ container: 4566, host: 4566 })
  .withAutoRemove(false)
  .withReuse()
  .start()

await container1.stop();

const container2 = await new LocalstackContainer('localstack/localstack:4.8')
  .withExposedPorts({ container: 4566, host: 4566 })
  .withAutoRemove(false)
  .withReuse()
  .start()

expect(container1.getId()).toBe(container2.getId()); // Ids not equals

Actually I looked the root cause and I think I found why. It's because Localstack module set an env var before create the container :

this.withEnvironment({
      LAMBDA_DOCKER_FLAGS: `${this.environment["LAMBDA_DOCKER_FLAGS"] ?? ""} -l ${LABEL_TESTCONTAINERS_SESSION_ID}=${reaper.sessionId}`,
});

Unfortunately this env var is not consistent and the reuse strategy use labels to choose if container could be reuse or not.

I haven't one solution to fix this because I don't known if this env var is necessary to run localstack. If it's required then it could be great to add a note in the doc for this point or maybe you will propose a technical solution to fix this.

[cristianrgreco]

Hi @Yopadd.

I've copy/pasted your code and for me the test is passing, so I will need more info.

Regarding the LAMBDA_DOCKER_FLAGS, unless there is a 10 second delay between container1 stopping and container2 starting (meaning the reaper container gets deleted and recreated with a different session ID), this shouldn't be an issue as the session ID will be the same.

[Yopadd]

Hi,
My bad, you’re right, my example does work. Let me give more context: I’m trying to reuse the LocalStack container between two integration test sessions. So yes, I get a new reaper container each time, and I see where I went wrong.

I found a workaround, I’m using a generic container without those environment variables since I don’t actually need them.

Why am I doing this? Because I use OpenSearch and it takes forever to start up! I’m trying to avoid that delay to save about 30 seconds on my integration tests. It’s really helpful when I’m running tests multiple times a day locally. 😄

[cristianrgreco]

I’m trying to reuse the LocalStack container between two integration test sessions

Could you not configure setupFiles to start the LocalStackContainer once for all tests, and then configure your tests to run in parallel, instead of starting different test sessions?

Regardless I guess this issue can be closed?

[Yopadd]

I already use setupFiles to start the LocalStackContainer globally. When I mention "test sessions," I’m referring to running npm test multiple times in a row.

Anyway, I’ve managed to solve it now and have a clearer understanding of how withReuse works. Thanks for your help ! I’ll close this issue.