Should Testcontainers modules drop the default image version?

[HofmeisterAn]

The Testcontainers for .NET modules always come with a pre-configured image version. Updating the version is tricky because we don't want to cause breaking changes for developers. On the other hand, we also don't want to include versions that are too outdated or possibly affected by security issues. In our best practices, we already recommend that developers override and pin the image version.

I'd like to discuss whether we should do the same as Java (and probably other language implementations) and remove the default image version. Instead, developers would need to provide the image/version up front when creating a container builder instance or at least call WithImage(string).

See also: #1407

WDYT?

[digital88]

NodeJs TC did the same recently. Seems like this is the way to go. The only downside is that newer images could be incompatible with builder internal implementation, like Kafka #1353 (comment).

[HofmeisterAn]

You're right, it won't be immediately clear to developers which images are compatible OOB.

Java has been using this approach for quite a while, and it doesn't seem to have caused any major issues so far. It could still be worth looking into ways to give developers better guidance, though.

We could stick with the suggested approach: #1407, adopt a similar mechanism to what Node uses, and leverage Dependabot to automatically detect image version updates and breaking changes.

Edit: I think this is actually much better than the current situation, because we're actively being informed of breaking image versions. I will create an issue and collect necessary information/tasks.

[HofmeisterAn]

Migrating to the new constructor

Starting with release 4.10.0, the parameterless container builder constructors will be obsolete. All modules now require you to explicitly provide the container image when creating a builder instance. The module documentation contains information about the official container image repository for each module. Do not use the latest tag as it is considered a bad practice and not recommended.

Old usage:

var builder = new ModuleContainerBuilder();

New usage:

var builder = new ModuleContainerBuilder("repository:tag");

Why the change?

1. Default image versions are no longer provided to prevent outdated or insecure images.
2. Developers should explicitly specify the image and tag they need.
3. This change aligns with other Testcontainers implementations.

[kieronlanning]

Is there an option to specify the tag only, maybe using a :{tag} syntax? Then the default repository could still be used, leaving people to focus on the versioning instead.

[HofmeisterAn]

No, not yet. It's something we can consider as long as we can properly design the API and resolve the ambiguity around ctor parameters. I'm happy to review any proposal.

[bhehe]

I just encountered these changes when taking on new versions to chase another unrelated bug/issue and would suggest that offering the previously used default values somewhere/somehow as constants would have been very helpful and eased the pain/burden a bit. That's basically the maneuver I just made to deal with things - even if it's just a temporary maneuver.

[digital88]

and would suggest that offering the previously used default values somewhere/somehow as constants would have been very helpful

This constant exists (but is deprecated) in every Module Builder, for example PostgreSql