commit | e592a25b2c969256df9234ef181212fbd8c35575 | [log] [tgz] |
---|---|---|
author | Jingwen Chen <jingwen@google.com> | Sun Nov 19 14:50:36 2023 +0000 |
committer | Chromeos LUCI <chromeos-scoped@luci-project-accounts.iam.gserviceaccount.com> | Mon Nov 20 00:28:53 2023 +0000 |
tree | 911069a3211ba2e3b654912412ebb899970060d8 | |
parent | 5e25e249ad733cee53727bd47a05e748ba947789 [diff] |
Revert "Enable --experimental_remote_cache_async." This reverts commit b02d39a8450d7cdbdbcca17671fcade4c1a690c3. Reason for revert: b/311319090#comment5 - lost observability in JSON profile. Original change's description: > Enable --experimental_remote_cache_async. > > This flag moves the "uploading outputs" step out of the action and into > an async thread. This enables dependent actions to start executing > immediately without being blocked on network activity (assuming there's > a free core). > > In a full build, there are ~594 such "uploading outputs" tasks, each > taking anywhere from sub-second to more than a minute. > > I suspect that given the long time chromeos-base/chromeos-chrome takes > by itself in the critical path in the latter of the build, any deferred > uploads can happen in parallel then, therefore speeding up the former > half of the build. > > https://ui.perfetto.dev/#!/?s=6dfcd3e7b11dd64f5f25004048a20343cb62edcf1ce8bf35cabbebc05fb2d83e > -> search "upload outputs" > > Note that this is experimental, and we should pay close attention to the > e2e latency of postsubmit builds once this is submitted. > > BUG=b:311319090 > TEST=CQ > > Change-Id: I5433a93c74dd79bb608b815b801dd2a95d0afe39 > Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/bazel/+/5035462 > Tested-by: Jingwen Chen <jingwen@google.com> > Reviewed-by: Shuhei Takahashi <nya@chromium.org> > Commit-Queue: Jingwen Chen <jingwen@google.com> BUG=b:311319090 Change-Id: I306917d09edd114436b44bc19f20da854cdd758d Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/bazel/+/5040046 Auto-Submit: Jingwen Chen <jingwen@google.com> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com> Reviewed-by: Matt Stark <msta@google.com> Commit-Queue: Matt Stark <msta@google.com>
This repository provides the implementation to build ChromeOS with Bazel.
For building ChromeOS with Bazel, use the following repo
command to check out with a few additional repositories.
$ mkdir ~/chromiumos $ cd ~/chromiumos # If you have access to the internal manifests: $ repo init -u https://chrome-internal.googlesource.com/chromeos/manifest-internal -g default,bazel -b snapshot # Otherwise: $ repo init -u https://chromium.googlesource.com/chromiumos/manifest -g default,bazel -b snapshot $ repo sync -c -j 16 $ cd src
-g default,bazel
is important to check out some additional repositories needed to build with Bazel.snapshot
branch rather than main
because Bazel‘s caching logic requires all inputs to match exactly, so you’re better off working from the snapshot
branch that was already built by the Snapshot/CQ builders rather than working from main
and picking up whatever commit happened to be at ToT at the time you ran repo sync
. You‘ll be at most 40 minutes behind ToT, and you’ll have the best chance of getting cache hits to speed your builds.repo init
command atop an existing checkout.Unless otherwise specified, examples in this doc assume that your current directory is ~/chromiumos/src
.
We support two configurations to build ChromeOS with Bazel:
/etc/portage
in the chroot, including cros workon
states of packages. Also, this is the only way you’re going to get remote cache hits right now. On the other hand, you still need to set up a CrOS SDK chroot.First, enter the CrOS SDK chroot with cros_sdk
command, which will create a new one if you haven't already. Then run the following command to create the amd64-host
sysroot.
(cr) $ /mnt/host/source/src/scripts/create_sdk_board_root --board amd64-host --profile sdk/bootstrap
This will create /build/amd64-host
. This sysroot contains the Portage configuration that is used when building host tool packages. i.e., CBUILD.
You can then proceed to create the target board's sysroot:
(cr) $ setup_board --board amd64-generic --public
If you're attempting to build a public image while using an internal manifest, the --public
flag allows you to do that, which is useful when attempting to recreate a CQ/Snapshot failure for build targets that use public manifests on the CI bots, such as amd64-generic. Omit the flag if you do want to build internal packages.
Now that you have configured your chroot, you can invoke a build with the standard cros build-packages
command, except that you need to pass the extra option --bazel
to build with Bazel.
To build a single Portage package, e.g. sys-apps/attr
:
$ cros build-packages --board=amd64-generic --bazel sys-apps/attr
To build all packages included in the ChromeOS test image:
$ cros build-packages --board=amd64-generic --bazel
Upon successful completion, packages are installed to the sysroot inside the CrOS SDK chroot.
/mnt/host/source/chromite/bin/bazel
instead of /usr/bin/bazel
. Read the following section to see how to specify build targets.cros workon
states in the CrOS SDK chroot are ignored even if they exist, and the live (9999) version of packages (if they exist and are not marked as CROS_WORKON_MANUAL_UPREV
) will be chosen by default. This means you can edit your source code and feel confident that the correct packages are getting rebuilt, though it might cause some build issues when live ebuilds are not prepared for Bazel builds. Note that you'll get no remote cache hits from CI builds today.Before you start building a package you need to ensure that which bazel
prints a path under your depot_tools checkout. The wrapper script provided by depot_tools
performs additional tasks besides running the real bazel
executable.
The syntax for specifying a Portage package is:
@portage//<host|target>/<category>/<package>`.
host
means the build host (CBUILD), and target
means the cross-compiled target (CHOST) specified by the BOARD
environment variable.
Now you're ready to start building. To build a single Portage package, e.g. sys-apps/attr
:
$ BOARD=amd64-generic bazel build @portage//target/sys-apps/attr
To build all packages included in the ChromeOS base image:
$ BOARD=amd64-generic bazel build @portage//target/virtual/target-os:package_set
A package_set
is a special target that also includes the target's PDEPENDs.
To build a package for the host, use the host
prefix:
$ BOARD=amd64-generic bazel build @portage//host/app-shells/bash
To build all packages included in the ChromeOS test image:
$ BOARD=amd64-generic bazel build @portage//target/virtual/target-os:package_set @portage//target/virtual/target-os-dev:package_set @portage//target/virtual/target-os-test:package_set
When you run Bazel inside the CrOS SDK chroot, you can simply use the standard cros build-image
command to build ChromeOS images.
The rest of the section describes the very experimental way to build ChromeOS images under Bazel outside the CrOS SDK chroot.
We have the following targets to build images:
@portage//images:chromiumos_minimal_image
: Minimal image that contains sys-apps/baselayout
and sys-kernel/chromeos-kernel
only.@portage//images:chromiumos_base_image
: Base image.@portage//images:chromiumos_dev_image
: Dev image.@portage//images:chromiumos_test_image
: Test image.Building a ChromeOS image takes several hours. Most packages build in a few minutes, but there are several known heavy packages, such as chromeos-base/chromeos-chrome
that takes 2-3 hours. You can inject prebuilt binary packages to bypass building those packages. See Injecting prebuilt binary packages for more details. To make chromeos-base/chromeos-chrome
build faster, you can also use Goma.
After building an image, you can use cros_vm
command available in CrOS SDK to run a VM locally. Make sure to copy an image out from bazel-bin
as it's not writable by default.
$ cp bazel-bin/external/_main~portage~portage/images/chromiumos_base_image.bin /tmp/ $ chmod +w /tmp/chromiumos_base_image.bin $ chromite/bin/cros_vm --start --board=amd64-generic --image-path /tmp/chromiumos_base_image.bin
You can use VNC viewer to view the VM.
$ vncviewer localhost:5900
You can also use cros_vm
command to stop the VM.
$ chromite/bin/cros_vm --stop
By default you can‘t tab complete the @portage//
repository. This is because bazel doesn’t provide support for tab completing external repositories. By setting export ENABLE_PORTAGE_TAB_COMPLETION=1
in your .bashrc
/.profile
, bazel
will create a @portage
symlink in the workspace root (i.e., ~/chromiumos/src
). This allows the bazel tab completion to work, but comes with one caveat. You can no longer run bazel build //...
because it will generate analysis errors. This is why this flag is not enabled by default.
The @portage
symlink has another added benefit, you can easily browse the generated BUILD.bazel
files.
The run_tests.sh
script runs currently available tests:
$ portage/tools/run_tests.sh
Optionally, you can skip running some tests by specifying some of the following environment variables when running run_tests.sh
: SKIP_CARGO_TESTS=1
, SKIP_BAZEL_TESTS=1
, SKIP_PORTAGE_TESTS=1
.
Bazel is able to correctly reuse content from the cache when all inputs are identified to it so it can detect when they change. Since our toolchain and our host tools (e.g. gsutil) are not yet fully hermetic, it‘s possible that you’ll run into problems when tools not yet tracked by Bazel are updated. In these situations we've found it useful to run bazel clean --expunge
to clear cached artifacts that seem not to be cleared without the --expunge
flag.
If you find you need the --expunge
flag, please file a bug to let the Bazelification team know about the non-hermeticity so we can fix the problem.
portage/
... for building Portage packages (aka Alchemy)bin/
... executablescommon/
... common Rust/Go librariesbuild_defs/
... build rule definitions in Starlarkrepo_defs/
... additional repository definitionsprebuilts/
... defines prebuilt binariessdk/
... defines the base SDKtools/
... misc small tools for developmentworkspace_root/
... contains various files to be symlinked to the workspace root, including WORKSPACE.bazel
and BUILD.bazel
You can speed up the build by enabling remote Bazel caching with RBE. To do this, follow this instruction to authenticate.
After authentication, make sure that you restart the Bazel instance by running bazel shutdown
.
Sometimes you want to enter an ephemeral CrOS chroot where a package build is failing to inspect the environment interactively.
To enter an ephemeral CrOS chroot, run the following command:
$ BOARD=arm64-generic bazel run @portage//target/sys-apps/attr:debug -- --login=after
This command will give you an interactive shell after building a package. You can also specify other values to --login
to choose the timing to enter an interactive console:
--login=before
: before building the package--login=after
: after building the package (default)--login=after-fail
: after failing to build the packageBuilding chromeos-base/chromeos-chrome
takes 2-3 hours, but you can use Goma to make it as fast as less than 1 hour.
To use Goma, please follow Goma for Chromium contributors (or go/chrome-linux-build if you‘re a Googler) and run goma_auth login
for authentication. Please make sure that you perform authentication inside the chroot if you’re going to run bazel build
inside the chroot, and do that outside the chroot if you're going to run it outside the chroot.
After authentication, you can just run bazel build
with USE_GOMA=true
to enable Goma.
$ USE_GOMA=true BOARD=amd64-generic bazel build @portage//chromeos-base/chromeos-chrome
You can also run build_packages
with --run-goma
to run it with Goma.
$ build_packages --bazel --board=amd64-generic --run-goma
In the case your work is blocked by some package build failures, you can workaround them by injecting prebuilt binary packages via command line flags.
For every ebuild
target under @portage//internal/packages/...
, an associated string flag target is defined. You can set a gs://
URL of a prebuilt binary package to inject it.
For example, to inject a prebuilt binary packages for chromeos-chrome
, you can set this option:
--@portage//internal/packages/stage1/target/board/chromiumos/chromeos-base/chromeos-chrome:114.0.5715.0_rc-r2_prebuilt=gs://chromeos-prebuilt/board/amd64-generic/postsubmit-R114-15427.0.0-49533-8783437624917045025/packages/chromeos-base/chromeos-chrome-114.0.5715.0_rc-r2.tbz2
You can run generate_chrome_prebuilt_config.py to generate the prebuilt config for the current version of chromeos-chrome.
% BOARD=amd64-generic portage/tools/generate_chrome_prebuilt_config.py
When performing changes to eclasses
, build_packages
, chromite
or other things that cache bust large parts of the graph, it might be beneficial to pin the binary packages for already built packages so you don't need to rebuild them when iterating on your changes. You can use the generate-stage2-prebuilts script to do this:
$ BOARD=amd64-generic ./bazel/portage/tools/generate-stage2-prebuilts
This will scan your bazel-bin
directory for any existing binpkgs and copy them to ~/.cache/binpkgs
. It will then generate a prebuilts.bazelrc
that contains various --config
options. The prebuilts.bazelrc
is invalid after you repo sync
since it contains package version numbers. Just re-run the script after a repo sync
to regenerate the prebuilts.bazelrc
and it will pin the packages with versions that still exist in your bazel-bin
.
Running a build with pinned packages:
$ BOARD=amd64-generic bazel build --config=prebuilts/stage2-board-sdk @portage//target/sys-apps/attr
In case you need to extract the contents of a binary package so you can easily inspect it, you can use the xpak split
CLI.
bazel run //bazel/portage/bin/xpak:xpak -- split --extract libffi-3.1-r8.tbz2 libusb-0-r2.tbz2
If you'd like to run the tests every time you commit, add the following. You can skip it with git commit --no-verify
.
cd ~/chromiumos/src/bazel ln -s ../../../../../src/bazel/portage/tools/run_tests.sh .git/hooks/pre-commit