Fuchsia development#

pw_bluetooth_sapphire: Battle-tested Bluetooth with rock-solid reliability

//pw_bluetooth_sapphire/fuchsia currently contains the Fuchsia build targets for building, running, and testing the bt-host and bt-hci-virtual packages.

Fuchsia’s Sapphire Bluetooth stack integration uses the bt-host core package which is built from Pigweed CI, uploaded to CIPD, and rolled automatically. The bt-host package is assembled into products in any Fuchsia build which uses Bluetooth. The bt-hci-virtual package is included in some builds for testing. See bt-host README for more details on product assembly.

Note

Every bazelisk invocation needs --config=fuchsia whenever the target or dependency needs to specify @fuchsia_sdk backends for Pigweed and the target platform is Fuchsia.

Accessing ffx from a Pigweed environment#

The ffx command is available as a subcommand of pw:

pw ffx help

Testing#

Running tests#

First, ensure the emulator is running or hardware running Fuchsia is connected. Then run a test package with:

bazelisk run --config=fuchsia //pw_bluetooth_sapphire/fuchsia/host/l2cap:test_pkg

Flags can also be passed to the test binary:

bazelisk run --config=fuchsia //pw_bluetooth_sapphire/fuchsia/host/l2cap:test_pkg \
  -- --gtest-filter="*Example" --severity=DEBUG

Note

If the test is unable to connect to the emulator, run pw ffx target remove --all first to clean your machine’s target list.

You can also run the presubmit step that will start an emulator and run all tests, but this is slow:

pw presubmit --step bthost_package

Emulator#

To start the emulator, use one of the following commands:

bazelisk run @fuchsia_products//:core.x64.emu -- --headless
# OR
bazelisk run @fuchsia_products//:minimal.arm64.emu -- --headless

To stop the running emulator, use the following command:

pw ffx emu stop --all

Building#

To build the bt-host package, use one of the following commands:

bazelisk build --config=fuchsia //pw_bluetooth_sapphire/fuchsia/bt_host:pkg.arm64

bazelisk build --config=fuchsia //pw_bluetooth_sapphire/fuchsia/bt_host:pkg.x64

The bt-host.far package will end up in a Bazel build directory that will be printed in the command output. For example: bazel-out/aarch64-fastbuild-e2b/bin/pw_bluetooth_sapphire/fuchsia/bt_host/bt-host.far. Note that bazel-out is symlinked from the root Pigweed directory.

Use the prebuilt in fuchsia.git#

fuchsia.git developers can copy/link the bt-host.far file to //prebuilt/connectivity/bluetooth/bt-host/<arch>/ and rename it to bt-host to replace the prebuilt that Fuchsia uses.

Working with devices#

Inspect#

To query the current state of the bt-host component Inspect hierarchy, run:

  1. pw ffx inspect list | grep bt-host to find the component’s <moniker>

  2. pw ffx inspect show "<moniker>"

    • Note that the full moniker from step 2 should be in quotations, e.g. pw ffx inspect show "core/bluetooth-core/bt-host-collection\:bt-host_000".

    • Wildcards can be passed into the selector as needed, e.g. pw ffx inspect show "core/bluetooth-core/bt-host-collection*".

Editor configuration#

Clangd#

Currently some manual steps are required to get clangd working with Fuchsia code (for example, for FIDL server files).

  1. Execute the following command to generate compile_commands.json. This needs to be done whenever the build graph changes.

    bazelisk run //:refresh_compile_commands_for_fuchsia_sdk

  2. Add this flag to your clangd configuration, fixing the full path to your Pigweed checkout:

    --compile-commands-dir=/path/to/pigweed/.compile_commands/fuchsia

Infrastructure#

Run Fuchsia presubmit tests#

Presubmits for bt-host are captured in a dedicated separate builder, pigweed-linux-bazel-bthost, rather than existing ones such as pigweed-linux-bazel-noenv.

On the builder invocation console, there are a number of useful artifacts for examining the environment during test failures. Here are some notable examples:

  • bt_host_package stdout: Combined stdout/stderr of the entire test orchestration and execution.

  • subrunner.log: Combined test stdout/stderr of test execution only.

  • target.log: The ffx target device’s logs.

  • ffx_config.txt: The ffx configuration used for provisioning and testing.

  • ffx.log: The ffx host logs.

  • ffx_daemon.log: The ffx daemon’s logs.

  • env.dump.txt: The environment variables when test execution started.

  • ssh.log: The SSH logs when communicating with the target device.

These presubmits can be also be replicated locally with the following command:

bazelisk run --config=fuchsia //pw_bluetooth_sapphire/fuchsia:infra.test_all

Note

Existing package servers must be stopped before running this command. To check for any existing package servers run lsof -i :8083 and make sure each of those processes are killed.

Note

You do not need to start an emulator beforehand to to run all tests this way. This test target will automatically provision one before running all tests.

Add a test to presubmit#

Fuchsia test packages are those defined with a Fuchsia SDK rule like fuchsia_unittest_package. All Fuchsia test packages need to be added to the Fuchsia presubmit step or they will not be tested.

To add new Fuchsia test packages to presubmit, add the test package targets to //pw_bluetooth_sapphire/fuchsia/BUILD.bazel.

Example:

# pw_bluetooth_sapphire/fuchsia/BUILD.bazel

qemu_tests = [
    "//pw_bluetooth_sapphire/fuchsia/bt_host:integration_test_pkg",
    ...
]

Uploading to CIPD#

Pigweed infrastructure uploads bt-host artifacts to fuchsia/prebuilt/bt-host and fuchsia/prebuilt/bt-hci-virtual via the pigweed-linux-bazel-bthost builder by building the top level infra target:

# Ensure all dependencies are built.
bazelisk build --config=fuchsia //pw_bluetooth_sapphire/fuchsia:infra

# Get builder manifest file.
bazelisk build --config=fuchsia --output_groups=builder_manifest //pw_bluetooth_sapphire/fuchsia:infra

The resulting file contains a cipd_manifests JSON field which references a sequence of JSON files specifying the CIPD package path and package file contents.

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