Goma client

Goma is a distributed compiler service for open-source project such as Chromium and Android. It's some kind of replacement of distcc+ccache.

NOTE: For non-Googler usage, please see Goma for Chromium Contributors.

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How Goma works

Goma hooks a compile request, and sends it to a backend compile server. If you have plenty of backend servers, a lot of compile can be processed in parallel, for example, -j100, -j500 or -j1000.

Also, the Goma backend caches the compile result. If the same compile request comes, the cached result is returned from the Goma cache server.

How to build

Goma client can be built on Linux, Mac, and Win.

Prerequisite

Use 64bit platform (Linux, Mac or Win).
Install depot_tools.
Install dependencies.
- On Mac, install Xcode.
- On Windows, install Visual Studio 2017. Community edition is OK.

Checkout source

$ gclient config https://chromium.googlesource.com/infra/goma/client
$ gclient sync
$ cd client

We assume the Goma client code is checked out to ${GOMA_SRC}. You can set this in your environment, but do not export it as it will make gomacc complain.

If you want to develop goma client, make goma client source unmanaged by gclient. Open .gclient file, and check "managed" value. If it's True, changed it to False. Otherwise, gclient will manage your repository, so your checkout can be unintentionally changed with gclient sync.

Move to client directory (which is under git repo), and configure git repository with your username and emails.

$ cd client
$ git config user.email 'foo@example.com'
$ git config user.name 'Your Name'

Build

$ cd "${GOMA_SRC}/client"
$ gclient sync
$ gn gen --args='is_debug=false' out/Release
$ ninja -C out/Release

Several important gn args

The build option can be modified with gn args.

is_debug=true/false
  Do debug build if true.
dcheck_always_on=true/false
  Enable DCHECK always (even in release build).
is_asan=true/false
  Use ASan build (with clang).
use_link_time_optimization=true/false
  Currently working only on Win. If true, /LTCG is enable.
use_lld=true/false
  Use lld for link (it will be fast)

Run unittest

$ cd "${GOMA_SRC}/client"
$ ./build/run_unittest.py --target=Release --build-dir=out

Coding style

Follow Google code style.

C++
Python

For C++11 features, we prefer to follow chromium guideline: http://chromium-cpp.appspot.com/

How to use

For Chromium/Android development

Goma can be integrated with Chromium/Android development easily.

Build goma client
Start compiler_proxy

$ "${GOMA_SRC}/client/out/Release/goma_ctl.py" start

For Chromium

In Chromium src, specify the following args in gn args

use_goma = true
goma_dir = "${GOMA_SRC}/client/out/Release"  (Replace ${GOMA_SRC} to your checkout)

Then build like the following:

$ cd /path/to/chromium/src/out/Release
$ ninja -j100 chrome

More details are avairable in chromium's build instructions.

For Android

$ source build/envsetup.sh
$ lunch aosp_arm-eng
$ GOMA_DIR="${GOMA_SRC}/client/out/Release" USE_GOMA=true make -j4

Here, -j4 is not related to Goma parallelism. Android internally sets -j500 (or -j with NINJA_REMOTE_NUM_JOBS environment variable) for Goma.

For general development

Build Goma client
Start compiler_proxy

$ ./goma_ctl.py ensure_start

Change your build script so that gomacc is prepended to compiler command. For example:

$ gomacc clang++ -c foo.cc

Build your product with make -j100, ninja -j100 or larger -j. Check http://localhost:8088 to see compiler_proxy is actually working.

You can use autoninja in depot_tools instead of specifying gomacc manually.

uazo/goma-client