This guide will walk you through setup and general use of Pigweed. We hope to make the setup process as smooth as possible. If any of this doesn't work, please let us know.
If you'd like to skip the detailed explanations, below is the shorter version of getting setup for Pigweed. If you run into trouble, look at the more in-depth guide below, starting at Prerequisites. The express setup configures Pigweed's watcher for three targets to give a taste of Pigweed:
To get setup:
(1) Make sure you have Git and Python installed and on your path.
(2) Clone Pigweed and bootstrap the environment (compiler setup & more). Be patient, this step downloads ~1GB of LLVM, GCC, and other tooling.
$ cd ~ $ git clone https://pigweed.googlesource.com/pigweed/pigweed ... $ cd pigweed $ source ./bootstrap.sh ...
(3) Configure the GN build.
$ gn gen out Done. Made 1047 targets from 91 files in 114ms
(4) Start the watcher. The watcher will invoke Ninja to build all the targets
$ pw watch out default stm32f429i ▒█████▄ █▓ ▄███▒ ▒█ ▒█ ░▓████▒ ░▓████▒ ▒▓████▄ ▒█░ █░ ░█▒ ██▒ ▀█▒ ▒█░ █ ▒█ ▒█ ▀ ▒█ ▀ ▒█ ▀█▌ ▒█▄▄▄█░ ░█▒ █▓░ ▄▄░ ▒█░ █ ▒█ ▒███ ▒███ ░█ █▌ ▒█▀ ░█░ ▓█ █▓ ░█░ █ ▒█ ▒█ ▄ ▒█ ▄ ░█ ▄█▌ ▒█ ░█░ ░▓███▀ ▒█▓▀▓█░ ░▓████▒ ░▓████▒ ▒▓████▀ 20200707 17:24:06 INF Starting Pigweed build watcher 20200707 17:24:06 INF Will build [1/1]: out default stm32f429i 20200707 17:24:06 INF Attaching filesystem watcher to $HOME/wrk/pigweed/... 20200707 17:24:06 INF Triggering initial build... ...
(5) Congratulations, you're ready to go! Now take Pigweed for a spin with the below steps.
(6) With the watcher running in a separate window, edit pw_status/status_test.cc
to make an expectation fail; for example, add EXPECT_EQ(0, 1);
in a test.
(7) Save the file. Observe the watcher rebuild & retest, and fail. Restore the test if you feel like it.
(8) Open the generated docs in out/docs/gen/docs/html/index.html
in your browser.
(9) Edit docs/getting_started.md
(this file!) and make any change. Save. See the watcher rebuild the docs. Reload your browser, and see the changes.
See below for equivalent Windows commands, and for more details on what each part does.
Note: After running bootstrap once, use source ./activate.sh
(or activate.bat
on Windows) to re-activate the environment without re-bootstrapping.
Linux
Most Linux installations should work out of box, and not require any manual installation of prerequisites beyond basics like git
and build-essential
. Make sure gcc is set to gcc-8.
macOS
On macOS you may get SSL certificate errors with the system Python installation. Run sudo pip install certifi
to fix this. If you get SSL errors with the Python from Homebrew try running the following commands to ensure Python knows how to use OpenSSL.
brew install openssl
brew uninstall python
brew install python
To flash firmware to a STM32 Discovery development board (and run pw test
) from macOS, you will need to install OpenOCD. Install Homebrew, then install OpenOCD with brew install openocd
.
Windows
To start using Pigweed on Windows, you'll need to install Git and Python (2.7 or above). We recommend you install Git to run from the command line and third party software.
If you plan to flash devices with firmware, you'll need to install OpenOCD and ensure it's on your system path.
Once you satisfied the prerequisites, you will be able to clone Pigweed and run the bootstrap that initializes the Pigweed virtual environment. The bootstrap may take several minutes to complete, so please be patient.
Linux/macOS
$ git clone https://pigweed.googlesource.com/pigweed/pigweed ~/pigweed $ cd ~/pigweed $ source ./bootstrap.sh
Windows
:: Run git commands from the shell you set up to use with Git during install. > git clone https://pigweed.googlesource.com/pigweed/pigweed %HOMEPATH%\pigweed > cd %HOMEPATH%\pigweed > bootstrap.bat
Below is a real-time demo with roughly what you should expect to see as output:
Congratulations, you are now set up to start using Pigweed!
After going through the initial setup process, your current terminal will be in the Pigweed development environment that provides all the tools you should need to develop on Pigweed. If you leave that session, you can activate the environment in a new session with the following command:
Linux/macOS
$ source ./activate.sh
Windows
> activate.bat
Some major changes may require triggering the bootstrap again, so if you run into host tooling changes after a pull it may be worth re-running bootstrap.
Pigweed's primary build system is GN/Ninja based. There are CMake and Bazel builds in-development, but they are incomplete and don't have feature parity with the GN build. We strongly recommend you stick to the GN build system.
GN (Generate Ninja) just does what it says on the tin; GN generates Ninja build files.
The default GN configuration generates build files that allow you to build host binaries, device binaries, and upstream documentation all in one Ninja invocation.
Run GN as seen below:
$ gn gen out
Note that out
is simply the directory the build files are saved to. Unless this directory is deleted or you desire to do a clean build, there's no need to run GN again; just rebuild using Ninja directly.
Now that we have build files, it's time to build Pigweed!
Now you could manually invoke the host build using ninja -C out
every time you make a change, but that's tedious. Instead, let's use pw_watch
.
Go ahead and start pw_watch
:
$ pw watch
When pw_watch
starts up, it will automatically build the directory we generated in out
. Additionally, pw_watch
watches source code files for changes, and triggers a Ninja build whenever it notices a file has been saved. You might be surprised how much time it can save you!
With pw watch
running, try modifying pw_status/public/pw_status/status.h
and watch the build re-trigger when you save the file.
See below for a demo of this in action:
Fun fact, you've been running the unit tests already! Ninja builds targeting the host automatically build and run the unit tests. Unit tests err on the side of being quiet in the success case, and only output test results when there's a failure.
To see the a test failure, you can modify pw_status/status_test.cc
to fail by changing one of the strings in the "KnownString" test.
Running tests as part of the build isn't particularly expensive because GN caches passing tests. Each time you build, only the tests that are affected (whether directly or transitively) by the code changes since the last build will be re-built and re-run.
Try running the pw_status
test manually:
$ ./out/host_{clang,gcc}_debug/obj/pw_status/test/status_test
Depending on your host OS, the compiler will default to either clang
or gcc
.
As mentioned previously, Pigweed builds for host by default. In the context of Pigweed, a Pigweed "target" is a build configuration that includes a toolchain, default library configurations, and more to result in binaries that run natively on the target.
Switch to the window running pw_watch
, and quit using ctrl+c
. To get pw_watch
to build the new STM32F429I-DISC1 target, re-launch by specifying which Ninja targets to build:
$ pw watch out default stm32f429i
This is equivalent to the following Ninja invocation:
$ ninja -C out default stm32f429i
Or since the "default" target builds host and docs,
$ ninja -C out host docs stm32f429i
Now pw_watch
is building for host and a device!
While tests run automatically on the host, it takes a few more steps to get tests to run automatically on a device, too. Even though we've verified tests pass on the host, it's crucial to verify the same with on-device testing. We've encountered some unexpected bugs that can only be found by running the unit tests directly on the device.
Connect any number of STM32F429I-DISC1 boards to your computer using the mini USB port on the board (not the micro USB). Pigweed will automatically detect the boards and distribute the tests across the devices. More boards = faster tests!
To allow Ninja to run tests on an arbitrary number of devices, Ninja will send test requests to a server running in the background. Launch the server in another window using the command below (remember, you'll need to activate the Pigweed environment first).
$ stm32f429i_disc1_test_server
Note: If you attach or detach any more boards to your workstation you'll need to relaunch this server.
We can tell GN to use the testing server by enabling a build arg specific to the stm32f429i-disc1 target.
$ gn args out # Append this line to the file that opens in your editor to tell GN to run # on-device unit tests. pw_use_test_server = true
Whenever you make code changes and trigger a build, all the affected unit tests will be run across the attached boards!
See the demo below for an example of what this all looks like put together:
In addition to the markdown documentation, Pigweed has a collection of information-rich RST files that are built by the default invocation of GN. You will find the documents at out/docs/gen/docs/html
.
You can build the documentation manually by with the command below.
$ ninja -C out docs
This concludes the introduction to developing with Pigweed. If you'd like to see more of what Pigweed has to offer, feel free to dive into the per-module documentation. If you run into snags along the way, please let us know!