name: Build Backend

on:
  # allow manual dispatch
  workflow_dispatch:
  # run on PRs
  pull_request:
    paths-ignore:
      - 'frontend/**'

concurrency:
  group: ${{ github.ref }}
  cancel-in-progress: true

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout
        uses: actions/checkout@v2

      - name: Set up JDK
        uses: actions/setup-java@v1
        with:
          java-version: 17

      - name: Cache Maven Deps
        uses: actions/cache@v2
        with:
          path: $GITHUB_WORKSPACE/.m2/repository
          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
          restore-keys: |
            ${{ runner.os }}-maven-

      - name: Build backend
        run: mvn --batch-mode --errors --fail-at-end --show-version --no-transfer-progress -Dmaven.repo.local=$GITHUB_WORKSPACE/.m2/repository install