Tulsi - an Xcode Project Generator For Bazel

Building and installing

To use Tulsi, clone this repository and run build_and_run.sh. By default this will install the Tulsi.app inside $HOME/Applications. Additionally, following options are available:

• -b: Bazel binary that Tulsi should use to build and install the app (Default is bazel)
• -d: The folder where to install the Tulsi app into (Default is $HOME/Applications)
• -x: The Xcode version Tulsi should be built for (Default is 13.2.1)

Integrating into your project

If your project can be built with Bazel 5.0.0 or newer, you can integrate Tulsi into your project.

Put the following content into your WORKSPACE file:

TULSI_COMMIT_HASH = "518f18da4948192c72074e07fa1dfe15858d40f4"

http_archive(
    name = "tulsi",
    url = "https://github.com/bazelbuild/tulsi/archive/{0}.tar.gz".format(TULSI_COMMIT_HASH),
    strip_prefix = "tulsi-{0}".format(TULSI_COMMIT_HASH),
    sha256 = "92c89fcabfefc313dafea1cbc96c9f68d6f2025f2436ee11f7a4e4eb640fa151",
)

Now you can run Tulsi with the following command:

bazel run @tulsi//:tulsi

You can also generate an Xcode project with the following command:

bazel run  -- @tulsi//:tulsi -- --genconfig "/path/to/your.tulsiproj:target" --outputfolder="/path/to/output"

Replace "/path/to/your.tulsiproj:target with the location of your Tulsi project and the target you want to generate the Xcode project for. Replace the /path/to/output with the directory's path where you want the generated Xcode project to be. Both paths need to be absolute path since bazel run will change the execution directory.

The TULSI_COMMIT_HASH is the git commit hash of the Tulsi you want to use. When you want to update Tulsi, you can replace the value of TULSI_COMMIT_HASH with the new commit hash you want. In this way, you can easily update Tulsi across the whole team.

If you do not know the sha256 of the new Tulsi archive you want to use, you can remove the sha256 attribute. Then when you do bazel run @tulsi//:tulsi you will say a debug log like this:

DEBUG: Rule 'tulsi' indicated that a canonical reproducible form can be obtained by modifying arguments sha256 = "92c89fcabfefc313dafea1cbc96c9f68d6f2025f2436ee11f7a4e4eb640fa151"

If you trust the source, you can then use the sha256 value in the log.

Notes

Tulsi-generated Xcode projects use Bazel to build, not Xcode. Building in Xcode will cause it to only run a script; the script invokes Bazel to build the configured Bazel target and copies the artifacts to where Xcode expects them to be. This means that many common components of an Xcode project are handled differently than you may be used to. Notable differences:

• BUILD files are the source of truth; most changes made to your Xcode project won't affect the build.
  • Adding new sources to the Xcode project won't include them in your app; they must be added to BUILD files.
  • Changes made to your BUILD files, such as adding new library dependencies, are incorporated automatically when building your generated project. The only time you need to re-run Tulsi is if you want to add additional build targets or have new source files show up in Xcode for editing.
  • The Info.plist file is governed entirely by BUILD rules in Bazel and is not displayed in the Xcode UI.
  • Changes to compilation flags (i.e. -DHELLO) should be made in the BUILD files in order to affect the build; changes made to compilation settings in the Xcode UI will only affect indexing. You may want to regenerate your project using Tulsi after modifying compilation flags.
• Tulsi will set some Tulsi-specific flags for bazel invocations, some of which may affect Bazel caching. In order to maximize cache re-use when building from the command line, try using the user_build.py script which is located in the generated xcodeproj at <xcodeproj>/.tulsi/Scripts/user_build.py.

Tulsi project and config settings

Tulsi projects contain a few settings which control various behaviors during project generation and builds.

• Bazel build flags, customizable per compilation mode (dbg and opt)
• Bazel build startup flags, also customizable per compilation mode
• Generation platform configuration: Target platform and arch used during project generation.
  • Can change from targeting iOS sim to iOS device or from iOS to macOS. Setting this improperly shouldn't break your project although it may potentially worsen generation and build performance.
• Generation compilation mode: Bazel compilation mode (dbg or opt, no fastbuild) used during project generation.
  • Defaults to dbg, swap to opt if you normally build Release builds in Xcode (i.e. profiling your app). Setting this improperly shouldn't break your project although it may potentially worsen generation and build performance.
• Prioritize Swift: set this to inform Tulsi that it should use Swift-specific flags during project generation.
  • Defaults to No, swap to Yes if your project contains Swift (even in its dependencies). Setting this improperly shouldn't break your project although it may potentially worsen generation and build performance.