plan/example-rust: fix the test with new sdk and optimize build

[laurentsenta]

• update the SDK,
• use a two-step "download package" - "build the main.rs" file in Dockerfile to speed-up iterations,
• Replace the temporary sdk-rust rewrite by a release (Fix: unwrap event & fix groups typo. sdk-rust#14),
• Update the test structure to have examples as part of integration,
• Fix & start cleaning the test scripts

[laurentsenta]

@mxinden @ackintosh ready for review!

[laurentsenta]

Note:
This PR adds the rust example to CI tests,
so I'm also using it as an opportunity to split the different tests (exec, docker, k8s, examples) and do some cleaning.

[mxinden]

Suggested change

	println!("TODO: why is this necessary to make the test go green?");
	let (client, _run_parameters) = testground::client::Client::new().await?;
	let (client, _run_parameters) = testground::client::Client::new().await?;
	client.wait_network_initialized().await?;

Would this resolve the failures as well @laurentsenta?

[laurentsenta]

That looks much more stable, thanks for the patch @mxinden

A quick note, the tests are still failing because the run.out file is empty, it's a file we collect (via --collect) at the end of the run. It looks like testground expects the SDK to write logs to a predefined folder,
Related code in the go-sdk:

https://github.com/testground/sdk-go/blob/d78f61eccaa37b0d941f98650bce5dbb8fd7b7f1/runtime/runenv_logger.go#L29

I'm going to skip this check:

• The rust SDK doesn't implement this logger yet as far as I can tell,
• More importantly, it might be a good time to discuss logging, do we even need that parser, why not "just" rely on stdout and stderr? (and get rid of the pretty.go file at the same time).
• When we fix A testground run might end with a status code = 0 despite the job failing (hence the need for the entrypoint.sh script) #1349 simply --wait'ing for a run will detect eventual failures.

[mxinden]

The rust SDK doesn't implement this logger yet as far as I can tell,

The rust-sdk does have the stdout hack:

https://github.com/testground/sdk-rust/blob/00c280fd23b75f19f80a45bcfa752298f109640d/src/background.rs#L375-L388

It does not support run.out.

More importantly, it might be a good time to discuss logging, do we even need that parser, why not "just" rely on stdout and stderr? (and get rid of the pretty.go file at the same time).

Off the top of my head, that would be the cleaner solution.

@laurentsenta what do you think of simply adding a touch run.out && before the entrypoint in the Dockerfile?

[laurentsenta]

It's a fair solution,

The way we test success with run.out made sort of sense without the --wait fix but it's arbitrary: https://github.com/testground/testground/blob/master/integration_tests/header.sh#L33-L38

If we both think it's worth looking into getting rid of run.* files, I'm in favor of not cluttering the images at all and starting relying on actual exit codes.

[mxinden]

If we both think it's worth looking into getting rid of run.* files, I'm in favor of not cluttering the images at all and starting relying on actual exit codes.

Off the top of my head I don't have a use-case for it. That said, I am not a testground expert. 👍 for proposing to remove it in this repository.