Auto merge of #136864 - Kobzol:citool, r=marcoieni

Rewrite the `ci.py` script in Rust

It would seem that I would learn by now that any script written in Python will become unmaintainable sooner or later, but alas..

r? `@marcoieni`

try-job: aarch64-gnu
try-job: dist-x86_64-linux-alt
try-job: x86_64-msvc-ext2

Fixes: https://github.com/rust-lang/rust/issues/137013

src/building/optimized-build.md

@@ -126,4 +126,4 @@ Here is an example of how can `opt-dist` be used locally (outside of CI):
 [`Environment`]: https://github.com/rust-lang/rust/blob/ee451f8faccf3050c76cdcd82543c917b40c7962/src/tools/opt-dist/src/environment.rs#L5
 
 > Note: if you want to run the actual CI pipeline, instead of running `opt-dist` locally,
-> you can execute `python3 src/ci/github-actions/ci.py run-local dist-x86_64-linux`.
+> you can execute `cargo run --manifest-path src/ci/citool/Cargo.toml run-local dist-x86_64-linux`.

src/tests/ci.md

@@ -28,7 +28,7 @@ Our CI is primarily executed on [GitHub Actions], with a single workflow defined
 in [`.github/workflows/ci.yml`], which contains a bunch of steps that are
 unified for all CI jobs that we execute. When a commit is pushed to a
 corresponding branch or a PR, the workflow executes the
-[`src/ci/github-actions/ci.py`] script, which dynamically generates the specific CI
+[`src/ci/citool`] crate, which dynamically generates the specific CI
 jobs that should be executed. This script uses the [`jobs.yml`] file as an
 input, which contains a declarative configuration of all our CI jobs.
 
@@ -299,7 +299,7 @@ platform’s custom [Docker container]. This has a lot of advantages for us:
 - We can avoid reinstalling tools (like QEMU or the Android emulator) every time
   thanks to Docker image caching.
 - Users can run the same tests in the same environment locally by just running
-  `python3 src/ci/github-actions/ci.py run-local <job-name>`, which is awesome to debug failures. Note that there are only linux docker images available locally due to licensing and
+  `cargo run --manifest-path src/ci/citool/Cargo.toml run-local <job-name>`, which is awesome to debug failures. Note that there are only linux docker images available locally due to licensing and
   other restrictions.
 
 The docker images prefixed with `dist-` are used for building artifacts while
@@ -443,7 +443,7 @@ this:
 [GitHub Actions]: https://github.com/rust-lang/rust/actions
 [`jobs.yml`]: https://github.com/rust-lang/rust/blob/master/src/ci/github-actions/jobs.yml
 [`.github/workflows/ci.yml`]: https://github.com/rust-lang/rust/blob/master/.github/workflows/ci.yml
-[`src/ci/github-actions/ci.py`]: https://github.com/rust-lang/rust/blob/master/src/ci/github-actions/ci.py
+[`src/ci/citool`]: https://github.com/rust-lang/rust/blob/master/src/ci/citool
 [rust-lang-ci]: https://github.com/rust-lang-ci/rust/actions
 [bors]: https://github.com/bors
 [homu]: https://github.com/rust-lang/homu

src/tests/docker.md

@@ -53,6 +53,15 @@ Some additional notes about using the interactive mode:
   containers. With the container name, run `docker exec -it <CONTAINER>
   /bin/bash` where `<CONTAINER>` is the container name like `4ba195e95cef`.
 
+The approach described above is a relatively low-level interface for running the Docker images
+directly. If you want to run a full CI Linux job locally with Docker, in a way that is as close to CI as possible, you can use the following command:
+
+```bash
+cargo run --manifest-path src/ci/citool/Cargo.toml run-local <job-name>
+# For example:
+cargo run --manifest-path src/ci/citool/Cargo.toml run-local dist-x86_64-linux-alt
+```
+
 [Docker]: https://www.docker.com/
 [`src/ci/docker`]: https://github.com/rust-lang/rust/tree/master/src/ci/docker
 [`src/ci/docker/run.sh`]: https://github.com/rust-lang/rust/blob/master/src/ci/docker/run.sh