unplugged-system/build/bazel/rules/apex

The Bazel APEX ruleset

Example

$ b build //path/to/module:com.android.module.apex --config=android

Code locations

The main entry point is the apex macro in //build/bazel/rules/apex/apex.bzl, which expands to the _apex rule implementation.

Related files in this directory include:

• cc.bzl for the C/C++ specific aspect that traverses into native dependencies
• toolchain.bzl for the host toolchain
• transition.bzl for the configuration transition to add APEX-specific configuration to dependencies, like the APEX name and min sdk version.
• apex_aab.bzl to repackage APEXes into multi-architecture Android app bundles and APK sets.
• apex_info.bzl contains ApexInfo and ApexMkInfo providers. These form the main interface of an APEX target.
• apex_key.bzl for the apex_key() rule
• apex_test.bzl for Starlark analysis tests

The bp2build converter (ConvertWithBp2build) is located here.

The mixed build handler (ProcessBazelQueryResponse) is located here.

Major features

• Build, compress, and sign APEX ext4 images and containers for all architectures/bitness
• Supports outputs: .apex, .capex (compressed apex), .aab (Android app bundle), .apks (APK set)
• Supports packaging prebuilts (e.g. tzdata), native shared libs, native binaries, sh_binary
• Works with apex, override_apex and apex_test Soong module types
• Supports AOSP and Google/Go APEX variants
• Supports standalone/unbundled APEX builds (fast for development) with b and full platform build with m (preloaded on system)
• Supports generating Mainline quality signals metadata files: required/provided libs, installed_files.txt
• Internal mainline build scripts is capable of building multi-arch AABs/APKs in a single Bazel invocation

Detailed features

• Bazel build settings/flags in //build/bazel/rules/apex/BUILD, like apexer_verbose and unsafe_disable_apex_allowed_deps_check
• ABI stability for native deps
  • ABI stable stubs are marked as required, and not included within the APEX
  • non-ABI stable transitive deps are copied into the APEX
• Supports testonly APEXes (converted from apex_test)
• Supports default certificates with product config
• Supports default file_contexts
• Supports allowed_deps.txt validation
• Supports apex_available validation
• Supports min_sdk_version validation
• Supports logging_parent, package_name, android_manifest, key.
• Supports apex_manifest.pb conversion
• Supports canned_fs_config generation
• Supports file_contexts generation
• Licensing: NOTICE.html.gz embedded in the APEX
• All host tools are built from source by Bazel, or vendored prebuilts
• All actions are fully sandboxed
• Ability to build metadata files on the command line with --output_groups=<coverage_files,backing_libs,...>

Guardrails / others

• --config=android is needed to build for the device. All APEX targets set target_compatible_with to android only - no host APEXes.
• Comprehensive set of rule analysis tests for in apex_test.bzl
• Example APEX in //build/bazel/examples/apex/...
• Unit and integration tests in //build/bazel/{examples,tests,rules}/apex/... and //build/soong/tests/...

Known issues / gap analysis (non-exhaustive)

Upcoming features are based on Roboleaf module conversion priorities, like Java, Rust, DCLA and API fingerprinting support.

• override_apex modules are converted to a regular apex with duplicated attributes. These are hidden by bp2build currently and will be cleaned up with macros in the future.
• Correct product platform transitions for apex_aab to mainline_modules_* products
• Java support
• Rust support