| .. default-domain:: python |
| |
| .. highlight:: sh |
| |
| .. _chapter-watch: |
| |
| -------- |
| pw_watch |
| -------- |
| |
| ``pw_watch`` is similar to file system watchers found in the web development |
| space. These watchers trigger a web server reload on source change, increasing |
| iteration. In the embedded space, file system watchers are less prevalent but no |
| less useful! The Pigweed watcher module makes it easy to instantly compile, |
| flash, and run tests upon save. |
| |
| .. image:: doc_resources/pw_watch_on_device_demo.gif |
| |
| .. note:: |
| |
| ``pw_watch`` currently only works with Pigweed's GN build. |
| |
| Module Usage |
| ============ |
| |
| The simplest way to get started with ``pw_watch`` is to launch it from a shell |
| using the Pigweed environment. |
| |
| |
| .. code:: sh |
| |
| $ pw watch |
| |
| By default, ``pw_watch`` will watch for repository changes and then trigger |
| Ninja builds sequentially for each subdirectory in ``${PIGWEED_ROOT}/out``. To |
| override this behavior, follow ``pw watch`` with paths to Ninja build |
| directories like so: |
| |
| .. code:: sh |
| |
| $ pw watch out/host out/disco |
| |
| The ``--patterns`` and ``--ignore_patterns`` arguments can be used to include |
| and exclude certain file patterns that will trigger rebuilds. |
| |
| Unit Test Integration |
| ===================== |
| |
| Thanks to GN's understanding of the full dependency tree, only the tests |
| affected by a file change are run when ``pw_watch`` triggers a build. By |
| default, host builds using ``pw_watch`` will run unit tests. To run unit tests |
| on a device as part of ``pw_watch``, refer to your device's |
| :ref:`target documentation<chapter-targets>`. |
