Running container inside container with custom network returns wrong gateway address

[HofmeisterAn]

Testcontainers returns the wrong gateway address if a container is running "inside" another container and has a custom network assigned. The current implementations just looks for networks with the name bridge:

testcontainers-dotnet/src/Testcontainers/Containers/TestcontainersContainer.cs

Line 391 in 446f002

var endpointSettings = this.container.NetworkSettings.Networks.TryGetValue("bridge", out var network) ? network : new EndpointSettings();

Originally posted by @ricardofmfreitasMP in #679 (comment)

[kiview]

This is interesting. In this case, I would expect the same issue for testcontainers-java. Can you conceptionally share a reproducer for us? (.NET reproducer is also fine, we can port it)

[HofmeisterAn]

That's my test example. L75 contains the "workaround".

[HofmeisterAn]

@kiview @eddumelendez @mdelapenya Do we know why we have the limitation and only consider networks with the name bridge? I know bridge is default, but what do we return in case of someone assigns a custom network?

[kiview]

To add some context, I tracked the changes in testcontainers-java. This behavior was introduced through testcontainers/testcontainers-java#2151.

Before, we did a more manual and dynamic lookup using this method, leveraging a running container:
https://github.com/testcontainers/testcontainers-java/blob/de1324ed2800eff4da326d0c23d281399d006bc0/core/src/main/java/org/testcontainers/dockerclient/DockerClientConfigUtils.java#L20