[Enhancement]: Properly define the execution order for container lifecycle hooks

[mdelapenya]

Proposal

At this moment, user-defined hooks are enqueued after the library-defined hooks (default logging, file copying). This is fine until we added the ability to add startup commands to the modules API, to run code right after the container is started.

It could be the case a user wants to add a startup command, and wait for something caused by that command, but because wait strategies are executed before the user-defined hooks (see

testcontainers-go/docker.go

Lines 1031 to 1056 in 1818971

	PostStarts: []ContainerHook{
	// first post-start hook is to wait for the container to be ready
	func(ctx context.Context, c Container) error {
	dockerContainer := c.(*DockerContainer)
	// if a Wait Strategy has been specified, wait before returning
	if dockerContainer.WaitingFor != nil {
	dockerContainer.logger.Printf(
	"🚧 Waiting for container id %s image: %s. Waiting for: %+v",
	dockerContainer.ID[:12], dockerContainer.Image, dockerContainer.WaitingFor,
	)
	if err := dockerContainer.WaitingFor.WaitUntilReady(ctx, c); err != nil {
	return err
	}
	}
	dockerContainer.isRunning = true
	return nil
	},
	},
	},
	}
	// always prepend default lifecycle hooks to user-defined hooks
	req.LifecycleHooks = append(defaultHooks, req.LifecycleHooks...)

) then it will be impossible for users to achieve that.

We propose define the following schema:

• make a distinction between user-defined hooks, and library hooks, where:
  • library hooks are mandatory (default logging, file copying)
  • user-defined hooks are optional, defined in the container request
  • Pre hooks: always run library hooks before user-defined hooks
  • Post hooks: always run library hooks after user-defined hooks