reclient-configs

This repository contains configuration script and reclient config extensions to support Chromium compilation on linux remotes via Reclient.

Usage

python3 configure_reclient.py --src_dir=/chromium_checkout/src

Help:

python3 configure_reclient.py --help

Details

Configuration steps

1. If a host machine is not linux, download linux clang toolchain and generate clang_remote_wrapper.
2. Generate reproxy and rewrapper configs.

Reproxy config merge

Reproxy config is based on the Chromium config template.

1. Load and substitute //buildtools/reclient_cfgs/reproxy_cfg_templates/reproxy.cfg.template with empty variables.
2. Merge reproxy.cfg.

Rewrapper configs merge

Rewrapper configs are based on the Chromium linux config.

1. Load //buildtools/reclient_cfgs/linux/<tool>/rewrapper_linux.cfg
2. Merge <tool>/rewrapper_base.cfg
3. Merge <tool>/rewrapper_<host_os>.cfg

Remote wrappers

clang_remote_wrapper is required to run cross-compilation. It replaces default clang path with a linux clang path and runs the linux version of the clang remotely.

Config merge process

1. Parse a config item and merge it with the existing one or create a new one.
2. If the value is a map, overwrite map items; if it's a list, append list items. Map-like and list-like items are hardcoded in ReclientCfg.
3. If the value is empty, clear the item.

This allows config merger to perform such modifications:

# Add/modify/remove items into a map-like value.
# This adds/modifies "OSFamily" and removes "label:action_default".
platform=OSFamily=linux,label:action_default=

# Add items into a list-like value.
inputs=src/new_file,src/new_file2

# Modify a simple value.
canonicalize_working_dir=false

# Fully replace list/map values by clearing it first.
labels=
labels=type=compile,compiler=clang,lang=cpp
platform=
platform=container-image=docker://...
inputs=
inputs=src/a_single_input

Path substitution

Configs may use path placeholders such as {src_dir}, {build_dir} in some variables of rewrapper configs. See ReclientCfg for the full list of supported variables.

Available placeholders can be found in Paths helper declaration. These placeheolders are substituted and final values are rebased onto Reclient-expected directory during the config write stage (see ReclientCfg).

Customization via external py script

You can pass a custom python script via --custom_py that may alter reproxy and rewrapper configs. The script receives some global objects from the configurator to make config handling easier (see ReclientConfigurator.load_custom_py()). It may implement some of these functions to be called by the configurator.

# Injected by reclient configurator.
Paths: object
ReclientCfg: object
FileUtils: object
ShellTemplate: object


# Called before the configuration begins.
def pre_configure():
    # Example: do not make remote_wrapper parameter relative. This is usable if
    # you run a custom Docker image with a baked-in wrapper which should be
    # called via absolute path.
    ReclientCfg.PATHS_RELATIVE_TO.pop('remote_wrapper')


# Called before writing reproxy.cfg.
def merge_reproxy_cfg(reproxy_cfg):
    reproxy_cfg = ReclientCfg.merge_cfg(
        reproxy_cfg,
        {
            # Increase verbosity for rbe debugging.
            'v': 2,
        })

    return reproxy_cfg


# Called before writing <tool>/rewrapper_<host_os>.cfg.
def merge_rewrapper_cfg(rewrapper_cfg, tool, host_os):
    # Merge with an existing config:
    rewrapper_cfg = ReclientCfg.merge_cfg(
        rewrapper_cfg
        {
            # Do not canonicalize working dir.
            'canonicalize_working_dir': false,
        })

    # Or rewrite it from scratch:
    rewrapper_cfg = {
        'platform' = {
            'container-image': 'docker://gcr.io/...'
            'OSFamily': 'linux',
        }
    }

    return rewrapper_cfg


# Called after the configuration has ended.
def post_configure():
    pass

Define large pool

Chromium now supports running actions on a different worker pool that might otherwise run into an OOM. See Reclient.

The actions affected are currently only Python actions marked with remote_worker=large.

You can define the name of the large pool by passing the following flag when running the tool:

python3 configure_reclient.py --large_pool_name=<NAME_OF_LARGE_POOL>

By default, these actions will use the default worker pool, same as other actions.