Bazel Build Server

Bazel implemention for build server protocol and mainly working with sourcekit-lsp.

Requirements

• Xcode 16.3
• Swift toolchain 6.1.0
• Enable global_index_store in .bazelrc
• Disable build --features=swift.use_explicit_swift_module_map

Getting Started

1. Creating a buildServer.json at the root of your project shown below.
   • The argv need to point at the buildserver executable
   • The target will be used by aquery to get all the compiler arguments and targets.
   • The sdk is what will be replaced for __BAZEL_XCODE_SDKROOT__
   • The indexStorePath is the location where all indexstore files are.
   • The indexDatabasePath is the location for index.db output
   • The aqueryArgs are additional arguments you can supply to the bazel aquery command
   • The extraIncludes are adding to the compiler arguments with option -I for addtional swiftmodule search paths
   • The extraFrameworks are adding to the copmiler arguments with option -F for framework search apth

{
  "name": "example-app",
  "argv": ["/Users/sean7218/bazel-build-server/target/debug/buildserver"],
  "version": "1.0.0",
  "bspVersion": "2.0.0",
  "languages": ["swift"],
  "target": "//App:App",
  "sdk": "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator18.4.sdk",
  "indexStorePath": "/Users/sean7218/bazel/buildserver/example-app/bazel-out/_global_index_store",
  "indexDatabasePath": "/Users/sean7218/bazel/buildserver/example-app/.index-db",
  "aqueryArgs": [],
  "extraIncludes": [],
  "extraFrameworks": []
}

2. Compile the build server by running cargo build, and the executable will be in bazel-build-server/target/debug/buildserver, and change the argv in the buildServer.json file as well.

cargo build

3. Before compile your project with bazel, you need to set the global index in .bazelrc file, then compile your project based on the target specified in the buildServer.json such as bazel build //App:App

# either this
build --features swift.use_global_index_store
build --features swift.index_while_building
# or
build --features swift.use_global_index_store
build --swiftcopt=-index-store-path
build --swiftcopt=$(OUTPUT_BASE)/indexstore

4. Open your project in vscode or neovim, you should be see logs both in sourcekit-lsp and bsp.log

5. Once the server is started Logging is stored in ~/.sourcekit-bsp/bsp.log, it is recommended to open it and see any issues.

Debugging

Here are some of the common errors:

1. standard library failed to load

• this means your path to sdk is wrong

2. execution_root not found

• when build server first start, it will run bazel info execution_root if the command fails, the build server will shutdown.

3. 👻 handle_initialize_request failed -> JsonError

• this usually means your buildServer.json is malformatted