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| <h1 id="testing-with-ci"><a class="header" href="#testing-with-ci">Testing with CI</a></h1> |
| <p>The primary goal of our CI system is to ensure that the <code>main</code> branch of |
| <code>rust-lang/rust</code> is always in a valid state by passing our test suite.</p> |
| <p>From a high-level point of view, when you open a pull request at |
| <code>rust-lang/rust</code>, the following will happen:</p> |
| <ul> |
| <li>A small <a href="#pull-request-builds">subset</a> of tests and checks are run after each |
| push to the PR. |
| This should help catch common errors.</li> |
| <li>When the PR is approved, the <a href="https://github.com/bors">bors</a> bot enqueues the PR into a <a href="https://bors.rust-lang.org/queue/rust">merge queue</a>.</li> |
| <li>Once the PR gets to the front of the queue, bors will create a merge commit |
| and run the <a href="#auto-builds">full test suite</a> on it. |
| The merge commit either contains only one specific PR or it can be a <a href="#rollups">"rollup"</a> which |
| combines multiple PRs together, to reduce CI costs and merge delays.</li> |
| <li>Once the whole test suite finishes, two things can happen. Either CI fails |
| with an error that needs to be addressed by the developer, or CI succeeds and |
| the merge commit is then pushed to the <code>main</code> branch.</li> |
| </ul> |
| <p>If you want to modify what gets executed on CI, see <a href="#modifying-ci-jobs">Modifying CI jobs</a>.</p> |
| <h2 id="ci-workflow"><a class="header" href="#ci-workflow">CI workflow</a></h2> |
| <!-- date-check: Oct 2024 --> |
| <p>Our CI is primarily executed on <a href="https://github.com/rust-lang/rust/actions">GitHub Actions</a>, with a single workflow defined |
| in <a href="https://github.com/rust-lang/rust/blob/HEAD/.github/workflows/ci.yml"><code>.github/workflows/ci.yml</code></a>, 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 |
| <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/citool"><code>src/ci/citool</code></a> crate, which dynamically generates the specific CI jobs that should be executed. |
| This script uses the <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/github-actions/jobs.yml"><code>jobs.yml</code></a> file as an |
| input, which contains a declarative configuration of all our CI jobs.</p> |
| <blockquote> |
| <p>Almost all build steps shell out to separate scripts. This keeps the CI fairly |
| platform independent (i.e., we are not overly reliant on GitHub Actions). |
| GitHub Actions is only relied on for bootstrapping the CI process and for |
| orchestrating the scripts that drive the process.</p> |
| </blockquote> |
| <p>In essence, all CI jobs run <code>./x test</code>, <code>./x dist</code> or some other command with |
| different configurations, across various operating systems, targets, and platforms. |
| There are two broad categories of jobs that are executed, <code>dist</code> and non-<code>dist</code> jobs.</p> |
| <ul> |
| <li>Dist jobs build a full release of the compiler for a specific platform, |
| including all the tools we ship through rustup. |
| Those builds are then uploaded |
| to the <code>rust-lang-ci2</code> S3 bucket and are available to be locally installed |
| with the <a href="https://github.com/kennytm/rustup-toolchain-install-master">rustup-toolchain-install-master</a> tool. |
| The same builds are also used |
| for actual releases: our release process basically consists of copying those |
| artifacts from <code>rust-lang-ci2</code> to the production endpoint and signing them.</li> |
| <li>Non-dist jobs run our full test suite on the platform, and the test suite of |
| all the tools we ship through rustup; |
| The amount of stuff we test depends on |
| the platform (for example some tests are run only on Tier 1 platforms), and |
| some quicker platforms are grouped together on the same builder to avoid wasting CI resources.</li> |
| </ul> |
| <p>Based on an input event (usually a push to a branch), we execute one of three |
| kinds of builds (sets of jobs).</p> |
| <ol> |
| <li>PR builds</li> |
| <li>Auto builds</li> |
| <li>Try builds</li> |
| </ol> |
| <h3 id="pull-request-builds"><a class="header" href="#pull-request-builds">Pull Request builds</a></h3> |
| <p>After each push to a pull request, a set of <code>pr</code> jobs are executed. |
| Currently, these execute the <code>x86_64-gnu-llvm-X</code>, <code>x86_64-gnu-tools</code>, <code>pr-check-1</code>, <code>pr-check-2</code> |
| and <code>tidy</code> jobs, all running on Linux. |
| These execute a relatively short |
| (~40 minutes) and lightweight test suite that should catch common issues. |
| More specifically, they run a set of lints, they try to perform a cross-compile check |
| build to Windows mingw (without producing any artifacts), and they test the |
| compiler using a <em>system</em> version of LLVM. |
| Unfortunately, it would take too many |
| resources to run the full test suite for each commit on every PR.</p> |
| <blockquote> |
| <p><strong>Note on doc comments</strong></p> |
| <p>Note that PR CI as of Oct 2024 <!-- datecheck --> by default does not try to |
| run <code>./x doc xxx</code>. This means that if you have any broken intradoc links that |
| would lead to <code>./x doc xxx</code> failing, it will happen very late into the full |
| merge queue CI pipeline.</p> |
| <p>Thus, it is a good idea to run <code>./x doc xxx</code> locally for any doc comment |
| changes to help catch these early.</p> |
| </blockquote> |
| <p>PR jobs are defined in the <code>pr</code> section of <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/github-actions/jobs.yml"><code>jobs.yml</code></a>. |
| Their results can be observed |
| directly on the PR, in the "CI checks" section at the bottom of the PR page.</p> |
| <h3 id="auto-builds"><a class="header" href="#auto-builds">Auto builds</a></h3> |
| <p>Before a commit can be merged into the <code>main</code> branch, it needs to pass our complete test suite. |
| We call this an <code>auto</code> build. |
| This build runs tens of CI jobs that exercise various tests across operating systems and targets. |
| The full test suite is quite slow; |
| it can take several hours until all the <code>auto</code> CI jobs finish.</p> |
| <p>Most platforms only run the build steps, some run a restricted set of tests; |
| only a subset run the full suite of tests (see Rust's <a href="https://forge.rust-lang.org/release/platform-support.html#rust-platform-support">platform tiers</a>).</p> |
| <p>Auto jobs are defined in the <code>auto</code> section of <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/github-actions/jobs.yml"><code>jobs.yml</code></a>. |
| They are executed on the <code>auto</code> branch under the <code>rust-lang/rust</code> repository, |
| and the final result will be reported via a comment made by bors on the corresponding PR. |
| The live results can be seen on <a href="https://github.com/rust-lang/rust/actions">the GitHub Actions workflows page</a>.</p> |
| <p>At any given time, at most a single <code>auto</code> build is being executed. |
| Find out more in <a href="#merging-prs-serially-with-bors">Merging PRs serially with bors</a>.</p> |
| <h3 id="try-builds"><a class="header" href="#try-builds">Try builds</a></h3> |
| <p>Sometimes we want to run a subset of the test suite on CI for a given PR, or |
| build a set of compiler artifacts from that PR, without attempting to merge it. |
| We call this a "try build". |
| A try build is started after a user with the proper |
| permissions posts a PR comment with the <code>@bors try</code> command.</p> |
| <p>There are several use-cases for try builds:</p> |
| <ul> |
| <li>Run a set of performance benchmarks using our <a href="https://github.com/rust-lang/rustc-perf">rustc-perf</a> benchmark suite. |
| For this, a working compiler build is needed, which can be generated with a |
| try build that runs the <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile">dist-x86_64-linux</a> CI job, which builds an optimized |
| version of the compiler on Linux (this job is currently executed by default |
| when you start a try build). |
| To create a try build and schedule it for a |
| performance benchmark, you can use the <code>@bors try @rust-timer queue</code> command combination.</li> |
| <li>Check the impact of the PR across the Rust ecosystem, using a <a href="crater.html">Crater</a> run. |
| Again, a working compiler build is needed for this, which can be produced by |
| the <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile">dist-x86_64-linux</a> CI job.</li> |
| <li>Run a specific CI job (e.g. Windows tests) on a PR, to quickly test if it |
| passes the test suite executed by that job.</li> |
| </ul> |
| <p>By default, if you send a comment with <code>@bors try</code>, the jobs defined in the <code>try</code> section of |
| <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/github-actions/jobs.yml"><code>jobs.yml</code></a> will be executed. |
| We call this mode a "fast try build". |
| Such a try build will not execute any tests, and it will allow compilation warnings. |
| It is useful when you want to |
| get an optimized toolchain as fast as possible, for a Crater run or performance benchmarks, |
| even if it might not be working fully correctly. |
| If you want to do a full build for the default try job, |
| specify its job name in a job pattern (explained below).</p> |
| <p>If you want to run custom CI jobs in a try build and make sure that they pass all tests and do |
| not produce any compilation warnings, you can select CI jobs to be executed by specifying a <em>job pattern</em>, |
| which can be used in one of two ways:</p> |
| <ul> |
| <li>You can add a set of <code>try-job: <job pattern></code> directives to the PR description (described below) and then |
| simply run <code>@bors try</code>. |
| CI will read these directives and run the jobs that you have specified. |
| This is |
| useful if you want to rerun the same set of try jobs multiple times, after incrementally modifying a PR.</li> |
| <li>You can specify the job pattern using the <code>jobs</code> parameter of the try command: <code>@bors try jobs=<job pattern></code>. |
| This is useful for one-off try builds with specific jobs. |
| Note that the <code>jobs</code> parameter has a higher priority than the PR description directives. |
| <ul> |
| <li>There can also be multiple patterns specified, e.g. <code>@bors try jobs=job1,job2,job3</code>.</li> |
| </ul> |
| </li> |
| </ul> |
| <p>Each job pattern can either be an exact name of a job or a glob pattern that matches multiple jobs, |
| for example <code>*msvc*</code> or <code>*-alt</code>. |
| You can start at most 20 jobs in a single try build. |
| When using |
| glob patterns in the PR description, you can optionally wrap them in backticks (<code>`</code>) to avoid GitHub rendering |
| the pattern as Markdown if it contains e.g. an asterisk. Note that this escaping will not work when using |
| the <code>@bors jobs=</code> parameter.</p> |
| <p>The job pattern needs to match one or more jobs defined in the <code>auto</code> or <code>optional</code> sections |
| of <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/github-actions/jobs.yml"><code>jobs.yml</code></a>:</p> |
| <ul> |
| <li><code>auto</code> jobs are executed before a commit is merged into the <code>main</code> branch.</li> |
| <li><code>optional</code> jobs are executed only when explicitly requested via a try build. |
| They are typically used for tier 2 and tier 3 targets.</li> |
| </ul> |
| <p>One reason to do a try build is to do a perf run, as described above, with <code>@rust-timer queue</code>. |
| This perf build then compares against some commit on main. |
| With <code>@bors try parent=<sha></code> you can base your try build and subsequent perf run on a specific commit on <code>main</code>, |
| to help make the perf comparison as fair as possible.</p> |
| <blockquote> |
| <p><strong>Using <code>try-job</code> PR description directives</strong></p> |
| <ol> |
| <li> |
| <p>Identify which set of try-jobs you would like to exercise. You can |
| find the name of the CI jobs in <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/github-actions/jobs.yml"><code>jobs.yml</code></a>.</p> |
| </li> |
| <li> |
| <p>Amend PR description to include a set of patterns (usually at the end |
| of the PR description), for example:</p> |
| <pre><code class="language-text">This PR fixes #123456. |
| |
| try-job: x86_64-msvc |
| try-job: test-various |
| try-job: `*-alt` |
| </code></pre> |
| <p>Each <code>try-job</code> pattern must be on its own line.</p> |
| </li> |
| <li> |
| <p>Run the prescribed try jobs with <code>@bors try</code>. As aforementioned, this |
| requires the user to either (1) have <code>try</code> permissions or (2) be delegated |
| with <code>try</code> permissions by <code>@bors delegate</code> by someone who has <code>try</code> |
| permissions.</p> |
| </li> |
| </ol> |
| <p>Note that this is usually easier to do than manually edit <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/github-actions/jobs.yml"><code>jobs.yml</code></a>. |
| However, it can be less flexible because you cannot adjust the set of tests |
| that are exercised this way.</p> |
| </blockquote> |
| <p>Try builds are executed on the <code>try</code> branch under the <code>rust-lang/rust</code> repository and |
| their results can be seen on <a href="https://github.com/rust-lang/rust/actions">the GitHub Actions workflows page</a>, |
| although usually you will be notified of the result by a comment made by bors on |
| the corresponding PR.</p> |
| <p>Multiple try builds can execute concurrently across different PRs, but there can be at most |
| a single try build running on a single PR at any given time.</p> |
| <p>Note that try builds are handled using the <a href="https://github.com/rust-lang/bors">new bors</a> implementation.</p> |
| <h3 id="modifying-ci-jobs"><a class="header" href="#modifying-ci-jobs">Modifying CI jobs</a></h3> |
| <p>If you want to modify what gets executed on our CI, you can simply modify the |
| <code>pr</code>, <code>auto</code> or <code>try</code> sections of the <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/github-actions/jobs.yml"><code>jobs.yml</code></a> file.</p> |
| <p>You can also modify what gets executed temporarily, for example to test a |
| particular platform or configuration that is challenging to test locally (for |
| example, if a Windows build fails, but you don't have access to a Windows machine). |
| Don't hesitate to use CI resources in such situations.</p> |
| <p>You can perform an arbitrary CI job in two ways:</p> |
| <ul> |
| <li>Use the <a href="#try-builds">try build</a> functionality, and specify the CI jobs that |
| you want to be executed in try builds in your PR description.</li> |
| <li>Modify the <a href="#pull-request-builds"><code>pr</code></a> section of <code>jobs.yml</code> to specify which |
| CI jobs should be executed after each push to your PR. |
| This might be faster than repeatedly starting try builds.</li> |
| </ul> |
| <p>To modify the jobs executed after each push to a PR, you can simply copy one of |
| the job definitions from the <code>auto</code> section to the <code>pr</code> section. |
| For example, the <code>x86_64-msvc</code> job is responsible for running the 64-bit MSVC tests. |
| You can copy it to the <code>pr</code> section to cause it to be executed after a commit is pushed |
| to your PR, like this:</p> |
| <pre><code class="language-yaml">pr: |
| ... |
| - image: x86_64-gnu-tools |
| <<: *job-linux-16c |
| # this item was copied from the `auto` section |
| # vvvvvvvvvvvvvvvvvv |
| - image: x86_64-msvc |
| env: |
| RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc --enable-profiler |
| SCRIPT: make ci-msvc |
| <<: *job-windows-8c |
| </code></pre> |
| <p>Then you can commit the file and push it to your PR branch on GitHub. |
| GitHub Actions should then execute this CI job after each push to your PR.</p> |
| <div class="warning"> |
| <p><strong>After you have finished your experiments, don't forget to remove any changes |
| you have made to <code>jobs.yml</code>, if they were supposed to be temporary!</strong></p> |
| <p>A good practice is to prefix <code>[WIP]</code> in PR title while still running try jobs |
| and <code>[DO NOT MERGE]</code> in the commit that modifies the CI jobs for testing purposes.</p> |
| </div> |
| <p>Although you are welcome to use CI, just be conscious that this is a shared |
| resource with limited concurrency. |
| Try not to enable too many jobs at once; |
| one or two should be sufficient in most cases.</p> |
| <h2 id="merging-prs-serially-with-bors"><a class="header" href="#merging-prs-serially-with-bors">Merging PRs serially with bors</a></h2> |
| <p>CI services usually test the last commit of a branch merged with the last commit |
| in <code>main</code>, and while that’s great to check if the feature works in isolation, |
| it doesn’t provide any guarantee the code is going to work once it’s merged. |
| Breakages like these usually happen when another, incompatible PR is merged |
| after the build happened.</p> |
| <p>To ensure a <code>main</code> branch that works all the time, we forbid manual merges. |
| Instead, all PRs have to be approved through our bot, <a href="https://github.com/bors">bors</a> (the software |
| behind it is called <a href="https://github.com/rust-lang/homu">homu</a>). |
| All the approved PRs are put in a <a href="https://bors.rust-lang.org/queue/rust">merge queue</a> |
| (sorted by priority and creation date) and are automatically tested one at the time. |
| If all the builders are green, the PR is merged, otherwise the failure is |
| recorded and the PR will have to be re-approved again.</p> |
| <p>Bors doesn’t interact with CI services directly, but it works by pushing the |
| merge commit it wants to test to specific branches (like <code>auto</code> or <code>try</code>), which |
| are configured to execute CI checks. |
| Bors then detects the outcome of the build by listening for either Commit Statuses or Check Runs. |
| Since the merge commit is |
| based on the latest <code>main</code> and only one can be tested at the same time, when |
| the results are green, <code>main</code> is fast-forwarded to that merge commit.</p> |
| <p>Unfortunately, testing a single PR at a time, combined with our long CI (~2 |
| hours for a full run), means we can’t merge a lot of PRs in a single day, and a |
| single failure greatly impacts our throughput. |
| The maximum number of PRs we can merge in a day is around ~10.</p> |
| <p>The long CI run times, and requirement for a large builder pool, is largely due |
| to the fact that full release artifacts are built in the <code>dist-</code> builders. |
| This is worth it because these release artifacts:</p> |
| <ul> |
| <li>Allow perf testing even at a later date.</li> |
| <li>Allow bisection when bugs are discovered later.</li> |
| <li>Ensure release quality since if we're always releasing, we can catch problems |
| early.</li> |
| </ul> |
| <h3 id="rollups"><a class="header" href="#rollups">Rollups</a></h3> |
| <p>Some PRs don’t need the full test suite to be executed: trivial changes like |
| typo fixes or README improvements <em>shouldn’t</em> break the build, and testing every |
| single one of them for 2+ hours would be wasteful. |
| To solve this, we regularly create a "rollup", a PR where we merge several pending trivial PRs so |
| they can be tested together. |
| Rollups are created manually by a team member using |
| the "create a rollup" button on the <a href="https://bors.rust-lang.org/queue/rust">merge queue</a>. |
| The team member uses their judgment to decide if a PR is risky or not.</p> |
| <h2 id="docker"><a class="header" href="#docker">Docker</a></h2> |
| <p>All CI jobs, except those on macOS and Windows, are executed inside that |
| platform’s custom <a href="https://github.com/rust-lang/rust/tree/HEAD/src/ci/docker">Docker container</a>. |
| This has a lot of advantages for us:</p> |
| <ul> |
| <li> |
| <p>The build environment is consistent regardless of the changes of the |
| underlying image (switching from the trusty image to xenial was painless for us).</p> |
| </li> |
| <li> |
| <p>We can use ancient build environments to ensure maximum binary compatibility, |
| for example <a href="https://github.com/rust-lang/rust/blob/HEAD/src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile">using older CentOS releases</a> on our Linux builders.</p> |
| </li> |
| <li> |
| <p>We can avoid reinstalling tools (like QEMU or the Android emulator) every time, |
| thanks to Docker image caching.</p> |
| </li> |
| <li> |
| <p>Users can run the same tests in the same environment locally by just running this command:</p> |
| <pre><code>cargo run --manifest-path src/ci/citool/Cargo.toml run-local <job-name> |
| </code></pre> |
| <p>This is helpful for debugging failures. |
| Note that there are only Linux Docker images available locally due to licensing and |
| other restrictions.</p> |
| </li> |
| </ul> |
| <p>The Docker images prefixed with <code>dist-</code> are used for building artifacts while |
| those without that prefix run tests and checks.</p> |
| <p>We also run tests for less common architectures (mainly Tier 2 and Tier 3 platforms) in CI. |
| Since those platforms are not x86, we either run everything |
| inside QEMU, or we just cross-compile if we don’t want to run the tests for that platform.</p> |
| <p>These builders are running on a special pool of builders set up and maintained for us by GitHub.</p> |
| <h2 id="caching"><a class="header" href="#caching">Caching</a></h2> |
| <p>Our CI workflow uses various caching mechanisms, mainly for two things:</p> |
| <h3 id="docker-images-caching"><a class="header" href="#docker-images-caching">Docker images caching</a></h3> |
| <p>The Docker images we use to run most of the Linux-based builders take a <em>long</em> time to fully build. |
| To speed up the build, we cache them using <a href="https://docs.docker.com/build/cache/backends/registry/">Docker registry |
| caching</a>, with the intermediate artifacts being stored on <a href="https://github.com/rust-lang/rust/pkgs/container/rust-ci">ghcr.io</a>. |
| We also push the built Docker images to ghcr, so that they can be reused by other tools |
| (rustup) or by developers running the Docker build locally (to speed up their build).</p> |
| <p>Since we test multiple, diverged branches (<code>main</code>, <code>beta</code> and <code>stable</code>), we |
| can’t rely on a single cache for the images, otherwise builds on a branch would |
| override the cache for the others. |
| Instead, we store the images under different |
| tags, identifying them with a custom hash made from the contents of all the |
| Dockerfiles and related scripts.</p> |
| <p>The CI calculates a hash key, so that the cache of a Docker image is |
| invalidated if one of the following changes:</p> |
| <ul> |
| <li>Dockerfile</li> |
| <li>Files copied into the Docker image in the Dockerfile</li> |
| <li>The architecture of the GitHub runner (x86 or ARM)</li> |
| </ul> |
| <h3 id="llvm-caching-with-sccache"><a class="header" href="#llvm-caching-with-sccache">LLVM caching with Sccache</a></h3> |
| <p>We build some C/C++ stuff in various CI jobs, and we rely on <a href="https://github.com/mozilla/sccache">Sccache</a> to cache |
| the intermediate LLVM artifacts. |
| Sccache is a distributed ccache developed by |
| Mozilla, which can use an object storage bucket as the storage backend.</p> |
| <p>With Sccache there's no need to calculate the hash key ourselves. |
| Sccache invalidates the cache automatically when it detects changes to relevant inputs, |
| such as the source code, the version of the compiler, and important environment variables. |
| So we just pass the Sccache wrapper on top of Cargo and Sccache does the rest.</p> |
| <p>We store the persistent artifacts on the S3 bucket, <code>rust-lang-ci-sccache2</code>. |
| So when the CI runs, if Sccache sees that LLVM is being compiled with the same C/C++ |
| compiler and the LLVM source code is the same, Sccache retrieves the individual |
| compiled translation units from S3.</p> |
| <h2 id="custom-tooling-around-ci"><a class="header" href="#custom-tooling-around-ci">Custom tooling around CI</a></h2> |
| <p>During the years, we developed some custom tooling to improve our CI experience.</p> |
| <h3 id="rust-log-analyzer-to-show-the-error-message-in-prs"><a class="header" href="#rust-log-analyzer-to-show-the-error-message-in-prs">Rust Log Analyzer to show the error message in PRs</a></h3> |
| <p>The build logs for <code>rust-lang/rust</code> are huge, and it’s not practical to find |
| what caused the build to fail by looking at the logs. |
| We therefore developed a bot called <a href="https://github.com/rust-lang/rust-log-analyzer">Rust Log Analyzer</a> (RLA) that |
| receives the build logs on failure, and extracts the error message automatically, |
| posting it on the PR thread.</p> |
| <p>The bot is not hardcoded to look for error strings, but was trained with a bunch |
| of build failures to recognize which lines are common between builds and which are not. |
| While the generated snippets can be weird sometimes, the bot is pretty |
| good at identifying the relevant lines, even if it’s an error we've never seen before.</p> |
| <h3 id="toolstate-to-support-allowed-failures"><a class="header" href="#toolstate-to-support-allowed-failures">Toolstate to support allowed failures</a></h3> |
| <p>The <code>rust-lang/rust</code> repo doesn’t only test the compiler on its CI, but also a |
| variety of tools and documentation. |
| Some documentation is pulled in via git submodules. |
| If we blocked merging rustc PRs on the documentation being fixed, we |
| would be stuck in a chicken-and-egg problem, because the documentation's CI |
| would not pass since updating it would need the not-yet-merged version of rustc |
| to test against (and we usually require CI to be passing).</p> |
| <p>To avoid the problem, submodules are allowed to fail, and their status is |
| recorded in <a href="https://rust-lang-nursery.github.io/rust-toolstate">rust-toolstate</a>. |
| When a submodule breaks, a bot automatically pings |
| the maintainers so they know about the breakage, and it records the failure on |
| the toolstate repository. |
| The release process will then ignore broken tools on |
| nightly, removing them from the shipped nightlies.</p> |
| <p>While tool failures are allowed most of the time, they’re automatically |
| forbidden a week before a release: we don’t care if tools are broken on nightly |
| but they must work on beta and stable, so they also need to work on nightly a |
| few days before we promote nightly to beta.</p> |
| <p>More information is available in the <a href="https://forge.rust-lang.org/infra/toolstate.html">toolstate documentation</a>.</p> |
| <h2 id="public-ci-dashboard"><a class="header" href="#public-ci-dashboard">Public CI dashboard</a></h2> |
| <p>To monitor the Rust CI, you can have a look at the <a href="https://p.datadoghq.com/sb/3a172e20-e9e1-11ed-80e3-da7ad0900002-b5f7bb7e08b664a06b08527da85f7e30">public dashboard</a> maintained by the infra team.</p> |
| <p>These are some useful panels from the dashboard:</p> |
| <ul> |
| <li>Pipeline duration: check how long the auto builds take to run.</li> |
| <li>Top slowest jobs: check which jobs are taking the longest to run.</li> |
| <li>Change in median job duration: check what jobs are slowest than before. Useful |
| to detect regressions.</li> |
| <li>Top failed jobs: check which jobs are failing the most.</li> |
| </ul> |
| <p>To learn more about the dashboard, see the <a href="https://docs.datadoghq.com/continuous_integration/">Datadog CI docs</a>.</p> |
| <h2 id="determining-the-ci-configuration"><a class="header" href="#determining-the-ci-configuration">Determining the CI configuration</a></h2> |
| <p>If you want to determine which <code>bootstrap.toml</code> settings are used in CI for a |
| particular job, it is probably easiest to just look at the build log. |
| To do this:</p> |
| <ol> |
| <li>Go to |
| <a href="https://github.com/rust-lang/rust/actions?query=branch%3Aauto+is%3Asuccess">https://github.com/rust-lang/rust/actions?query=branch%3Aauto+is%3Asuccess</a> |
| to find the most recently successful build, and click on it.</li> |
| <li>Choose the job you are interested in on the left-hand side.</li> |
| <li>Click on the gear icon and choose "View raw logs"</li> |
| <li>Search for the string "Configure the build"</li> |
| <li>All of the build settings are listed on the line with the text, <code>build.configure-args</code></li> |
| </ol> |
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