pw_watch#
Embedded development file system watcher
Stable
Automatically trigger build actions when source files change
Background#
In the web development space, file system watchers like nodemon and watchman are prevalent. These watchers trigger actions when files change (such as reloading a web server), making development much faster. In the embedded space, file system watchers are less prevalent but no less useful!
Our solution#
pw_watch is similar to file system watchers found in web development
tooling but is focused around embedded development use cases. After changing
source code, pw_watch can instantly compile, flash, and run tests.
pw watch running in fullscreen mode and displaying errors.#
Combined with the GN-based build which expresses the full dependency tree, only the exact tests affected by source changes are run.
The demo below shows pw_watch building for a STMicroelectronics
STM32F429I-DISC1 development board, flashing the board with the affected test,
and verifying the test runs as expected. Once this is set up, you can attach
multiple devices to run tests in a distributed manner to reduce the time it
takes to run tests.
Get started#
cd ~/pigweed
source activate.sh
pw watch
The simplest way to get started with pw_watch is to launch it from a shell
using the Pigweed environment as pw watch. By default, pw_watch watches
for repository changes and triggers the default Ninja build target at //out.
To override this behavior, provide the -C argument to pw watch.
See pw_watch how-to guide for more examples and pw_watch CLI reference for detailed CLI usage information.