Feat: Integration testing with testcontainers go

[flowchartsman]

Motivation

Instead of building a customized container, test using base image and testcontainers-go. This enables manual individual test execution, and will only create the integration container if tests are run which require it.

Modifications

• Integration container singleton using testcontainers-go
• Modify helper URLs to pull from mapped ports on integration container, ensuring that only tests which access these URLS will cause the integration container to get created.

Verifying this change

cd <repo root>/pulsar && go test -v -race ./...

• Make sure that the change passes the CI checks.

This change is already covered by existing integration tests.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): yes
  • docker library dependencies have been updated to avoid the http: invalid Host header error (Golang client fails to attach to streams with "http: invalid Host header" with go1.20.6, go1.19.11 moby/moby#45935)
• The public API: no
• The schema: no
• The default values of configurations: no
• The wire protocol: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable
• If a feature is not applicable for documentation, explain why?
  • this is a test-only feature

WIP

Some connection tests are failing, such as the "retry on multipl hostname" or producer connection tests, however it's unclear how these changes would suddenly cause this test to fail, so it's possible these are flakey.

Tasks:

• Collect output with go test -v and compare against vanilla repo in an attempt to identify tests that are passing, but shouldn't, and determine of the above errors are flakey tests or something different about the testcontainers-go environment
• allow container to (optionally) persist for local iteration on a single test or feature

[flowchartsman]

Some other benefits:

• no need for scripts in the happy pathway; the container is automatically created if needed and torn down after testing is complete
• code doesn't need to be copied into the container and built for every change, and with a little modification, the container could be made to persist by disabling the reaper container through the use of an environment variable or even a go run style container invocation allowing fast iteration on a single test or feature.
• the integration container and associated helper functions could be moved into another package, or even another module entirely, which would allow projects based on pulsar-client-go to use the same testing infrastructure. In particular, I'm thinking about [go]: reduce dependency #819, which would split pusar-perf into its own repo. Even though this particular code path does not do IT, it potentially could do so by using the shared IT container code from the main repo.

[flowchartsman]

Pending the changes in #1077, this PR might end up getting reworked such that the following code in helper_for_test.go

func serviceURL() string {
	return integration.URL("pulsar", "6650")
}

func serviceURLTLS() string {
	return integration.URL("pulsar+ssl", "6651")
}

func webServiceURL() string {
	return integration.URL("http", "8080")
}

func webServiceURLTLS() string {
	return integration.URL("https", "8443")
}

Becomes

AdminClient() *pulsaradmin.Client {
        return pulsaradmin.NewClient(pulsaradmin.ClientConfig{
		WebServiceURL:   integration.URL("https", "8443"),
		BKWebServiceURL: integration.URL("pulsar", "6650"),
                //etc
	})
}

AdminClientTLS() *pulsaradmin.Client {
        return pulsaradmin.NewClient(pulsaradmin.ClientConfig{
		WebServiceURL:   integration.URL("http", "8080"),
		BKWebServiceURL: integration.URL("pulsar+ssl", "6651"),
                //etc
	})
}

Which would then create the integration container only when one of the helper admin clients is used, while simultaneously dogfooding pulsar/pulsaradmin and increasing coverage. Which would be pretty darn slick.

[merlimat]

Let's remove these instead of commenting out