More refined dependency management for different app types

[bradhe]

This PR does a few different things.

1. Always setup a virtual environment for every app.
2. If the user is using requirements.txt (our legacy suggestion), then manage dependencies using that.
3. If the user is using pyproject.toml, use uv sync for setup.
4. If the user is using neither, do nothing.

It also adds some test coverage for running different types of apps via tower-runtime to ensure the behavior doesn't change over time.

[Copilot]

Pull Request Overview

This PR adds error handling for missing pyproject.toml files in the uv sync operation and introduces basic regression tests for the tower-runtime crate. The main change skips the sync operation when no pyproject.toml is present rather than allowing uv to fail.

• Adds early detection and graceful handling of missing pyproject.toml files
• Introduces comprehensive test coverage for LocalApp runtime with two example scenarios
• Updates Status enum to support equality comparisons needed for testing

Reviewed Changes

Copilot reviewed 11 out of 14 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
crates/tower-uv/src/lib.rs	Adds MissingPyprojectToml error variant and pre-sync validation
crates/tower-runtime/src/local.rs	Updates sync logic to gracefully handle missing pyproject.toml
crates/tower-runtime/src/lib.rs	Adds PartialEq trait to Status enum for test assertions
crates/tower-runtime/src/errors.rs	Maps new MissingPyprojectToml error to SpawnFailed
crates/tower-runtime/tests/local_test.rs	Adds comprehensive test suite with example apps
crates/tower-runtime/Cargo.toml	Adds config dev dependency for testing

Comments suppressed due to low confidence (2)

crates/tower-runtime/tests/local_test.rs:71

• The error message 'App should be running' is incorrect for an assertion that checks if status equals Status::Exited. It should be 'App should be exited' or 'App should have exited'.

    assert!(status == Status::Exited, "App should be running");

crates/tower-runtime/tests/local_test.rs:123

• The error message 'App should be running' is incorrect for an assertion that checks if status equals Status::Exited. It should be 'App should be exited' or 'App should have exited'.

    assert!(status == Status::Exited, "App should be running");

[Copilot]

The indentation is inconsistent with the surrounding code. The line should be indented to align with the other match arms above it.

Suggested change

	tower_uv::Error::MissingPyprojectToml => Error::SpawnFailed,
	tower_uv::Error::MissingPyprojectToml => Error::SpawnFailed,

[bradhe]

I don't understand this one? Maybe there's something messed up in my local enviro config.

[socksy]

isn't it just wrong?

[bradhe]

Seems to be to me? Thought maybe it was some hidden whitespace issue perhaps.

[socksy]

1. You can elide the let binding completely now, so just calling unbounded_channel
2. If that's the case, you could possibly elide this function completely?
3. Is there a reason we don't use a bounded channel? Unbounded channels use a linkedlist. I presume if we have a large enough bounded channel we're unlikely to ever get backpressure, and it may improve latency due to being friendlier to cpu cache?

[bradhe]

You're right about eliding the let binding, I think we can do that. The only purpose of this function is to manage the creation of our internal type, OutputSender and OutputReceiver. This kind of "hides" the fact that we use tokio under the hood.

Anyway, we might be able to push all this on to the user. I'd say lets experiment with that a bit later on.

[bradhe]

Actually you were right about eliding this whole thing away. Nice.

[socksy]

untested, but can probably do this?

Suggested change

	match test_uv_path(&self.uv_path).await {
	Ok(_) => true,
	Err(_) => false,
	}
	(&self.uv_path).await.is_ok()

[socksy]

LGTM, and the core logic doesn't seem to break when I throw some projects with requirements.txt at it etc? not 100% sure if I effectively tested it though 😅