CI for Arduino Libraries

arduino-ci allows you to quickly add continuous integration (CI) tests to Arduino libraries. It uses arduino-cli to install dependencies and then it compiles every example with every board.

Dependencies

• Linux-like operating system
• nix: https://nixos.org/guides/install-nix.html

Usage

Run arduino-ci/ci from the directory of an Arduino library. It will have a non-zero exit code if a compilation fails. When it runs, it creates an out directory with all dependency libraries and the compilation artifacts. We recommended adding the out directory to your version control system's ignore file (like .gitignore).

GitHub Actions example

Add the below code to a file named .github/workflows/ci.yaml to your library and push it to GitHub.

name: "CI"
on:
  pull_request:
  push:
jobs:
  ci:
    runs-on: ubuntu-20.04
    steps:
    - name: Checkout this repository
      uses: actions/checkout@v2
    - name: Cache for arduino-ci
      uses: actions/cache@v2
      with:
        path: |
          ~/.arduino15
        key: ${{ runner.os }}-arduino
    - name: Install nix
      uses: cachix/install-nix-action@v12
    - run: nix-shell -I nixpkgs=channel:nixpkgs-unstable -p arduino-ci --run "arduino-ci"

GitLab example

Add the below code to a file named .gitlab-ci.yml to your library and push it to GitLab.

image: nixos/nix:2.3.6

stages:
  - ci

ci:
  stage: ci
  script:
    - nix-shell -I nixpkgs=channel:nixpkgs-unstable -p arduino-ci --run "arduino-ci"

You may need to enable GitLab CI if you project was created before it was on by default.

Defaults

All examples in your library are compiled with the following boards by default:

• esp8266:esp8266:huzzah
• arduino:avr:leonardo
• arduino:avr:mega
• arduino:avr:micro
• arduino:avr:uno
• arduino:avr:yun
• arduino:sam:arduino_due_x
• arduino:samd:arduino_zero_native
• Intel:arc32:arduino_101

arduino-ci installs the cores for each of these boards.

Customization

There are two ways to customize arduino-ci.

• .arduino-ci.yaml config file in the top-level directory of your library (recommended)
• environment variables (for quick tests)

Yaml configurations are applied first and environment variables are applied last.

.arduino-ci.yaml configuration file

The configuration file supports this top-level mapping:

• skip_boards - skips default boards (list)
• add_boards - adds additional boards (list)
• only_boards - use only these boards (list)
• skip_additional_urls - skips default additional_urls (list)
• add_additional_urls - adds additional additional_urls (list)
• only_additional_urls - use only these additional_urls (list)
• library_archives - additional library archives to download (list, format: name=uri=hash)

.arduino-ci.yaml example

only_boards:
  - arduino:avr:leonardo
library_archives:
  - AStar32U4=https://github.com/pololu/a-star-32u4-arduino-library/archive/1.1.0.tar.gz=1z5mi80g2b4f9zbarl2kva2wr0flz8ym9nsb34p3rj5w4sq6zpdx

Determining the hash of a library archive

The easiest way to determine the hash of a library is to start with an invalid hash (0):

library_archives:
  - AStar32U4=https://github.com/pololu/a-star-32u4-arduino-library/archive/1.1.0.tar.gz=0

Then run arduino-ci. You should see something like:

$ ci/ci
Updating index: package_index.json downloaded
Platform arduino:[email protected] already installed
error: hash '0' has wrong length for hash type 'sha256'
unpacking...
path is '/nix/store/mxa0gfrnjmdr9hximfylykhzs75mshr2-AStar32U4'
Hash mismatch for AStar32U4=https://github.com/pololu/a-star-32u4-arduino-library/archive/1.1.0.tar.gz=0
Wanted: 0
   Got: 1z5mi80g2b4f9zbarl2kva2wr0flz8ym9nsb34p3rj5w4sq6zpdx

Use the "Got:" hash:

library_archives:
  - AStar32U4=https://github.com/pololu/a-star-32u4-arduino-library/archive/1.1.0.tar.gz=1z5mi80g2b4f9zbarl2kva2wr0flz8ym9nsb34p3rj5w4sq6zpdx

Then when you run it, it should work normally.

Environment variables

Environment variables should only be used to quickly override settings when testing something out.

• ARDUINO_CI_SKIP_BOARDS - skips default boards (comma separated)
• ARDUINO_CI_ADD_BOARDS - adds additional boards (comma separated)
• ARDUINO_CI_ONLY_BOARDS - use only these boards (comma separated)
• ARDUINO_CI_SKIP_ADDITIONAL_URLS - skips default additional_urls (comma separated)
• ARDUINO_CI_ADD_ADDITIONAL_URLS - adds additional additional_urls (comma separated)
• ARDUINO_CI_ONLY_ADDITIONAL_URLS - use only these additional_urls (comma separated)
• ARDUINO_CI_LIBRARY_ARCHIVES - additional library archives to download (semi-colon separated, format: name=uri=hash) For example: ARDUINO_CI_LIBRARY_ARCHIVES="PololuMenu=https://github.com/pololu/pololu-menu-arduino/archive/1.0.0.tar.gz=0a1lg5pbylcrl1fc69237z6acwr8cgpbdx8bl8jx3lz4vkvjx6yr".