Support Testcontainers for resource definition

[eddumelendez]

Hi, I landed in the project by looking at this issue to support Testcontainers for component tests.

I currently see this is how resources are provisioned:

For Redis container:

builder.AddRedis("basketcache")
    .WithDataVolume()
    .WithRedisCommander();

For Azure Redis:

builder.AddRedis("cache").AsAzureRedis()

Proposal

Provide an API to provide specific Resource definitions, let's say AspireResource. For the Redis example, it can use AzureRedisExtensions or Testcontainers Redis module. The API can be also used in case there are other ways to provision a Redis instance, so, developers can write their own implementation.

For Testcontainers Redis:

var redisContainer = new RedisBuilder()
  .WithImage("redis:7.0")
  .Build();

builder.AddRedis("cache", new TestcontainersAspireResource().WithContainer(redisContainer).Build()))

where TestcontainersAspireResource will start the container.

For Azure Redis:

builder.AddRedis("cache", new AzureAspireResource().WithExtension(new AzureRedisExtension()).Build())

Benefits

• Unify the experience for dev and test by using the same API to provide resources
• Generic API to define and start a container
• Support Docker network
• Integrates with Testcontainers Desktop
• Docker socket auto-detection
• Automatic resource cleanup
• Recently, reuse containers feature was added. So, the same instance can be shared cross-services

Also, by looking at the issues, some of them are already handled by Testcontainers. For example:

• Add support for PgVector extension to postgres resource #3052
  PGvector is compatible with current Testcontainers PostgreSQL implementation. For more info can look at the module https://testcontainers.com/modules/pgvector/
• Support stopping a running resource from an integration test #2899
  Ryuk is Testcontainers resource reaper, which is in charge of cleanup resources when the process is done.
• Proposal for Keycloak integration #1326
  Keycloack also has a Testcontainers implementation https://testcontainers.com/modules/keycloak/
• AddRabbitMQ method with volume mounts does not persist queues across restarts by default #2247
  Use RabbitMQ module with reuse functionality could help https://testcontainers.com/modules/rabbitmq/
• Make PgAdmin, RedisCommander, and MyPhpAdmin usable for remote resources #2116
  By using the Generic API users can enable it without waiting for this feature

All Testcontainers .NET are listed in the module catalog.

If there is no specific module the Testcontainers API is very fluent and allow the user to write their own definition.

var container = new ContainerBuilder()
  .WithImage("testcontainers/helloworld:1.1.0")
  .WithPortBinding(8080, true)
  .WithWaitStrategy(Wait.ForUnixContainer().UntilHttpRequestIsSucceeded(r => r.ForPort(8080)))
  .Build();

await container.StartAsync()
  .ConfigureAwait(false);

References

In the Java world, this integration has been done in the three major frameworks (Quarkus devservices, Micronaut test-resources, Spring Boot service connection). I would be very happy to chat and share more about it in order to find a similar experience in .NET ecosystem with Aspire.

[davidfowl]

I like the idea of bridging test containers as a custom resource type but I don't think we should aim to unify the API. Something like:

builder.AddTestContainerResource("name", () =>
{
    return new RedisBuilder().WithImage("redis:7.0").Build();
});

Would need to give some more thought to how connection strings etc work in this mode.

Also, by looking at the issues, some of them are already handled by Testcontainers. For example:

That's great but I'm not sure we need to lean on test containers here, the resource model is pretty capable 😄. I'm looking forward to an experiment in this space to see what comes out!

Thanks for the issue!

[ElanHasson]

fyi, I'm using test containers here not as a test, but for dev only : https://github.com/InfinityFlowApp/aspire-temporal/blob/main/src/InfinityFlow.Aspire.Temporal/TemporalServerContainerBuilderExtensions.cs#L31-L70

(yes, i later learned you can use temporal-admin image which has temporal-cli and many other things)

I do agree having a resource that can "speak test container" natively would be awesome.

[davidfowl]

Unrelated: @ElanHasson if you want to make your resource plug in a little more cleanly, you can write an IDistributedApplicationLifecycleHook that uses test containers to build container image.

https://github.com/InfinityFlowApp/aspire-temporal/blob/19ed3f9cc63b65951206d9cffccb0232dc89b371/src/InfinityFlow.Aspire.Temporal/TemporalServerContainerBuilderExtensions.cs#L101

This might be a very nice integration point between aspire and test containers.

[MadL1me]

I'm in big support for this issue, because it solves the problem of any custom integration (I was thinking about support for https://zitadel.com/ as IDP)