Reuse containers supported in DevServices?

[tmulle]

When I start up more than one Quarkus application that uses Mailpit in dev mode, I notice that each instance of Mailpit docker container gets started up rather than sharing one global instance.

This is my .testcontainers setting which shows reuse set to true.

 more ~/.testcontainers.properties
#Modified by Testcontainers
#Tue Mar 25 17:01:38 EDT 2025
docker.client.strategy=org.testcontainers.dockerclient.UnixSocketClientProviderStrategy
testcontainers.reuse.enable=true

I know it's setup properly because I see Keycloak and Mariadb look for and find existing containers and use them rather than creating their own instances.

[melloware]

@ggrebert @gsmet @geoand any ideas how to fix this I thought I set MailPit for Shared Dev Services like all other examples?

[ggrebert]

we must use a sharedcontainer.

the easiest way is to add a label to a container and find containers with this label.

It is a pattern used by lots of quarkus devservices extentions

[melloware]

@ggrebert any chance I can assign to you?

[melloware]

@ggrebert i think we have most everything else i think this is the step we are missing?

final Optional<ContainerAddress> maybeContainerAddress = KEYCLOAK_DEV_MODE_CONTAINER_LOCATOR.locateContainer(
                capturedDevServicesConfiguration.serviceName(),
                capturedDevServicesConfiguration.shared(),
                LaunchMode.current());

[ozangunalp]

There is a confusion between reusing (which depends on the testcontainers reuse) and sharing.

I agree that this use case is more of sharing a dev service between multiple applications in dev mode.
The first app launched in dev mode would create the service, by adding a specific label to the container and subsequent ones will first try discovering a running service using the label.

The dev service config would include properties like shared flag and serviceName for the label value.

A ContainerLocator is then used to look up running containers and returns the ContainerAddress with the host and mapped port.

[melloware]

cc @MayerMan