webrtc

WebRTC

The WebRTC library relies upon a relatively non-standard set of build tools from the chromium codebase (depot_tools, GN, ninja, etc). To avoid introducing dependencies on these tools in your build, this project pre-builds a copy of WebRTC and exposes corresponding bazel targets. This makes it trivial to use WebRTC in your bazel Linux (C++), iOS (Swift / Objective-C) and Android (Java) projects.

Linux (C++)

Add the following to your WORKSPACE file:

http_archive(
    name = "taxi_code_socialworkout_webrtc_linux",
    sha256 = "a21516985f438a23ee57d85fd87cdf8d99e4e6cfa29b6ff6a18685310d7a01f2",
    url = "https://code.taxi/download/webrtc-58-5-linux.tar.gz",
)

Then add deps to the WebRTC package from the appropriate cc_library() or cc_binary() targets in your BUILD files:

cc_library(
    ...
    copts = ["-fno-rtti"],
    deps = [ "@taxi_code_socialworkout_webrtc_linux//:rtc" ],
    ...
)

# or

cc_binary(
    ...
    copts = ["-fno-rtti"],
    deps = [ "@taxi_code_socialworkout_webrtc_linux//:rtc" ],
    ...
)

Linux Notes

Upstream WebRTC allows clients to gather and aggregate statistics as well as perform field trials by turning on feature code in binaries out in the field. This project links the default implementation (system_wrappers:metrics_default and system_wrappers:field_trial_default) for metrics and field trails. However, you can also provide your own implementation by not linking the two *.o files.

Additionally, WebRTC is compiled without runtime type information. Therefore, it is required that your client code be compiled with -fno-rtti to avoid linking errors (error: undefined reference to 'typeinfo for rtc::MessageHandler').

Note, this target can only be compiled from linux (not darwin). Depending on the platforms you build on, it may be desirable to omit relevant cc_library() and cc_binary targets from your bazel build command on darwin. If you want to build all targets omitting a single sub-tree run a command similar to bazel build -- ... -//foo/bar/....

Android (Java)

Download the Android SDK command line tools. Then point bazel to the location of your android SDK using the ANDROID_HOME environment variable or the path attribute of the android_sdk_repository rule in your WORKSPACE file.

Next, add the following to your WORKSPACE file:

http_archive(
    name = "taxi_code_socialworkout_webrtc_android",
    sha256 = "20444fc5bb6d653f04e504d60701a786ff40d436e23a8210949d62e3482189e6",
    url = "https://code.taxi/download/webrtc-58-5-android.tar.gz",
)

android_sdk_repository(
    name = "androidsdk",
    api_level = 24,
    build_tools_version = "24.0.3",
    # set $ANDROID_HOME environment variable or specify `path`
    # path = __workspace_dir__ + "/android_sdk_folder",
)

Finally, add deps to the WebRTC package from the appropriate android_library() or android_binary() targets in your BUILD files:

android_library(
    ...
    deps = [ "@taxi_code_socialworkout_webrtc_android//:rtc" ],
    ...
)

# or

android_binary(
    ...
    deps = [ "@taxi_code_socialworkout_webrtc_android//:rtc" ],
    ...
)

Android Notes

To test your application on a physical device run bazel mobile-install [android_target] with a connected device that has USB debugging enabled.

The default *_unsigned.apk file generated by android_binary() include debug symbols, are not zipaligned and are unsigned. To prepare a release build for upload to the Google Play Store run:

$ bazel -c opt [android_target]  # compile "optimized" without debug symbols
$ [build_tools_dir]/zipalign -v -p 4 ./bazel-bin/[android_target]_unsigned.apk \
  /tmp/android_aligned.apk
$ [build_tools_dir]/apksigner sign --ks [keystore.jks] \
  --out /tmp/android_release.apk /tmp/android_aligned.apk

Building a android_binary() on macOS currently requires --strategy=AndroidAapt=standalone due to #2597.

iOS (Swift / Objective-C)

Install XCode and the "iOS 8.4 Simulator" (XCode > Preferences > Components). Then, add the following to your WORKSPACE file:

http_archive(
    name = "taxi_code_socialworkout_webrtc_ios",
    sha256 = "40bd5af5af047da0d8cb4c08cfdbda76f0191e32b208cfcbd7f1d47fc15a632d",
    url = "https://code.taxi/download/webrtc-58-19-ios.tar.gz",
)

Next, add deps to the WebRTC package from the appropriate swift_library() or objc_library() targets in your BUILD files:

swift_library(
    ...
    deps = [ "@taxi_code_socialworkout_webrtc_ios//:rtc" ],
    ...
)

# or

objc_library(
    ...
    deps = [ "@taxi_code_socialworkout_webrtc_ios//:rtc" ],
    ...
)

iOS Notes

When importing framework headers use the WebRTC framework prefix. For example:

#import <WebRTC/RTCLogging.h>

Embedded frameworks are only supported on iOS 8.0+. Therefore set the minimum iOS version during build:

bazel build --ios_minimum_os=8.0

Also, when using Tulsi to build in Xcode and run using the ensure your build is configured for iOS 8.0+ only.

When building for a device (vs the simulator) specify the CPU architecture:

bazel build --ios_minimum_os=8.0 --ios_multi_cpus=armv7,arm64