GitHub Actions concurrency to cancel outdated runs

<p>My GitHub Actions workflows queue up multiple runs when I push rapidly. I want to cancel old runs when a new commit is pushed to the same branch, while still running all checks on main.</p>

<p>Concurrency groups for smart cancellation:</p> <div class="highlight"><pre><span></span><code><span class="c1"># .github/workflows/ci.yml</span> <span class="nt">name</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">CI</span> <span class="nt">on</span><span class="p">:</span> <span class="w"> </span><span class="nt">push</span><span class="p">:</span> <span class="w"> </span><span class="nt">branches</span><span class="p">:</span><span class="w"> </span><span class="p p-Indicator">[</span><span class="s">'**'</span><span class="p p-Indicator">]</span> <span class="w"> </span><span class="nt">pull_request</span><span class="p">:</span> <span class="c1"># Cancel previous runs on same branch (not on main):</span> <span class="nt">concurrency</span><span class="p">:</span> <span class="w"> </span><span class="nt">group</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">${{ github.workflow }}-${{ github.ref }}</span> <span class="w"> </span><span class="nt">cancel-in-progress</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">${{ github.ref != 'refs/heads/main' }}</span> <span class="nt">jobs</span><span class="p">:</span> <span class="w"> </span><span class="nt">test</span><span class="p">:</span> <span class="w"> </span><span class="nt">runs-on</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">ubuntu-latest</span> <span class="w"> </span><span class="nt">steps</span><span class="p">:</span> <span class="w"> </span><span class="p p-Indicator">-</span><span class="w"> </span><span class="nt">uses</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">actions/checkout@v4</span> <span class="w"> </span><span class="p p-Indicator">-</span><span class="w"> </span><span class="nt">run</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">uv run pytest</span> <span class="c1"># For PRs: cancel if new commit pushed to the PR branch</span> <span class="c1"># concurrency:</span> <span class="c1"># group: pr-${{ github.event.pull_request.number }}</span> <span class="c1"># cancel-in-progress: true</span> <span class="c1"># For deployments: queue instead of cancel</span> <span class="c1"># concurrency:</span> <span class="c1"># group: deploy-${{ github.ref }}</span> <span class="c1"># cancel-in-progress: false # Queue, don't cancel deploys</span> </code></pre></div> <p>Environment-level concurrency (from GitHub Environments):</p> <div class="highlight"><pre><span></span><code><span class="nt">jobs</span><span class="p">:</span> <span class="w"> </span><span class="nt">deploy</span><span class="p">:</span> <span class="w"> </span><span class="nt">environment</span><span class="p">:</span><span class="w"> </span><span class="l l-Scalar l-Scalar-Plain">production</span> <span class="w"> </span><span class="c1"># GitHub Environments have built-in concurrency via protection rules</span> <span class="w"> </span><span class="c1"># Can require manual approval before deployment</span> </code></pre></div> <p>Key points: - group key scopes the concurrency -- same group = cancel previous - cancel-in-progress: false queues rather than cancels (good for deployments) - github.ref includes branch name -- prevents cross-branch cancellation - Different groups for test vs deploy -- don't cancel running deployments - PR concurrency group by PR number not branch (multiple PRs from same branch)</p>