Bazel Build Examples

This collection of examples demonstrates how to use Bazel on iOS builds with Xcode 11 and iOS 13.

HelloWorld

The HelloWorld iOS example is a Swift project that was generated by Xcode 11.3.1 and remains in the same structure as when it was generated. The project file was removed and replaced with a Bazel build.

The ios/HelloWorld folder contains a makefile named Makefile.bazel that shows the Bazel commands required to build. It also contains commands to install and launch the build on a simulator.

To build the HelloWorld app in Bazel, install it on the simulator, and then run the app on the simulator, run this command from the Terminal:

$ cd ios/HelloWorld
$ make -f Makefile.bazel build_app

HelloWorld2

The HelloWorld2 iOS example is the same as the HelloWorld example, but with a BUILD file in the subfolder HelloWorld2.

To build the HelloWorld2 app in Bazel, install it on the simulator, and then run the app on the simulator, run this command from the Terminal:

$ cd ios/HelloWorld2
$ make -f Makefile.bazel build_app

HelloWorld3

The HelloWorld3 iOS example is the same as the HelloWorld2 example, but with a second swift_library containing one new Swift file, where SwiftLib depends on library Controllers.

To build the HelloWorld3 app in Bazel, install it on the simulator, and then run the app on the simulator, run this command from the Terminal:

$ cd ios/HelloWorld3
$ make -f Makefile.bazel build_app

Bazel Commands

There are various new commands used when building with Bazel for iOS so I have placed them in a makefile called Makefile.bazel so it is easy to remember how to run bazel.

First, open a Terminal window and navigate to the ios/HelloWorld2 folder.

$ cd ios/HelloWorld2

The bazel build command used for iOS is:

$ bazel build --apple_platform_type=ios HelloWorld2/HelloWorld2

Using make you can just type:

$ make -f Makefile.bazel build_app

To install the app just built with bazel onto the simualator:

$ make -f Makefile.bazel install

To run the app on the simulator:

$ make -f Makefile.bazel launch

To build, install, and launch the app all at once:

$ make -f Makefile.bazel run

After installing Tulsi and configuring the project, you can create the Xcode project file from the command line. It will also launch Xcode.

$ make -f Makefile.bazel generate_xcode_project

Installing Tulsi

Installing Tulsi with Bazel 2.0.0 requires a few modifications to the installation script. The script build_and_run.sh is used to build the Tulsi app and is setup to use Xcode 11.2.1 as of 3/8/2020.

To build Tulsi with Xcode 11.3.1 you need to make two changes:

• Open the .bazelrc file and find this on line 3: build --xcode_version=11.2.1. Change 11.2.1 to 11.3.1 and save the file.

• Open the WORKSPACE file and find this on line 3: git_repository(. Replace the entire git_repository function with this one:

git_repository(
    name = "build_bazel_rules_apple",
    remote = "https://github.com/bazelbuild/rules_apple.git",
    tag = "0.19.0",
)

Run the build script:

$ ./build_and_run.sh

If the build succeeded, you should see this:

Target //:tulsi up-to-date:
  bazel-bin/tulsi.zip
INFO: Elapsed time: 35.487s, Critical Path: 29.57s
INFO: 43 processes: 28 darwin-sandbox, 15 local.
INFO: Build completed successfully, 82 total actions

The Tulsi app is automatically launched:

Contributing

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