Continuous Integration

Reddit - Programmer Humor - Works on my Machine

---

How to start?

• Many ways to do CI; use the one you prefer
• Github Actions
• Azure DevOps
• Circle CI
• Travis
List of CI services

• We will use Github Actions

Turing Way - CC-BY 4.0 licence. DOI: 10.5281/zenodo.3332807

---

Create a workflow

• Create folder .github/workflows

• Add a name_of_workflow.yml

---

When should the workflow be executed?

name: Build documentation and upload artifact

on:
  pull_request:
    branches: main
  push:
    branches:
      - "*"
    tags:
      - "v*"
  schedule:
    - cron: 0 9 * * 1
  workflow_call:
  workflow_dispatch:

---

Run on pull-request

on:
  pull_request:
    branches: main

Triggered when

• A pull request is made against the main branch

• Can make a list of branches [development, main, "v[0-9].[0-9]+.[0-9]+"]

• Cheatsheet for patterns

---

Run on push

on:
  push:
    branches:
      - "*"
    tags:
      - "v*"

Triggered when

• A push a commited to any branch

• A tag starting with v is created

---

Run on schedule

 schedule:
    - cron: 0 9 * * 1

Triggered when

• Specific UCT time in POSIX cron syntax

• Easy interpreter at: Crontab.guru

---

Run from another workflow

on:
  workflow_call:

• Incredibly powerful feature that makes it possible to make chains of workflows

jobs:
  build-docs:
    uses: ./.github/workflows/build_docs.yml
  deploy:
    needs: [build-docs, pre-commit]

---

Chained workflow example

Source: jorgensd/dolfinx_mpc

---

Run workflow manually

on:
  workflow_dispatch:

Run a workflow manually on CI

---

Environment variables

env:
  PUBLISH_DIR: ./_build/html
  PYTHON_VERSION: "3.10"

• Can be accessed as ${PUBLISH_DIR} or ${{ env.PUBLISH_DIR }} depending on context

---

Setting up a set of jobs

jobs:
  build:
    runs-on: ubuntu-22.04
    steps:
      - name: Run echo
        run:  echo "HELLO WORLD"
      - name: Multiple commands
        run: |
          echo "HI"
          ls

• Github supports several architectures

  • Ubuntu (20.04, 22.04)

  • Windows (2019, 2022)

  • Mac (macos-11, macos-12)

---

Complex dependencies? Use containers!

jobs:
  build:
    runs-on: ubuntu-22.04
    container: ghcr.io/fenics/dolfinx/dolfinx:nightly
    steps:
      - name: Run echo
        run:  python3 -c "import dolfinx; print(dolfinx.__version__)

• Docker containers hosted anywhere

---

Complex steps to setup your problem? Create an action!

Github marketplace for actions: https://github.com/marketplace?category=&query=&type=actions

jobs:
  clone-repo:
    runs-on: ubuntu-22.04
    steps:
      - name: Checkout current repo on current branch
        uses: actions/checkout@v4
      - name: Look at current files
        run: ls

---

Exercise

• Make a branch in your repository

• Create a workflow that runs on Ubuntu 22.04

• Workflow should run:

  • On every commit on main

  • On every pull request to any branch

• List the files in the repository

---

Actions can take inputs

jobs:
  clone-repo:
    runs-on: ubuntu-22.04
    steps:
      - name: Setup python
        uses: actions/setup-python@v4
        with:
          python-version: ${PYTHON_VERSION}

---

You can create your own actions

    - name: Install DOLFINx
      uses: ./.github/actions/install-dolfinx
      with:
        dolfinx: main
        ufl: main
        ffcx: main
        basix: main
        petsc_arch: ${PETSC_ARCH}

---

You can use actions across repositories

Example from: https://github.com/jorgensd/actions

name: Use a remote action
on:
  push:
    branches: ["dokken/ci"]
jobs:
  test:
    runs-on: ubuntu-latest
    container: ghcr.io/fenics/dolfinx/dolfinx:nightly
    steps:
      - name: "Use remote action"
        uses: jorgensd/actions/install-dolfinx@v0.1.0

---

Upload data

      - name: Upload artifact
        uses: actions/upload-artifact@v3
        with:
          path: ${{ env.PUBLISH_DIR }}
          if-no-files-found: error
          name: documentation

---

Download data

      - name: Download docs artifact
        uses: actions/download-artifact@v3
        with:
          name: documentation
          path: "./public"