better-setup-docker v1: static CLI + socket verification

README.md

@@ -0,0 +1,9 @@
+# better-setup-docker
+
+Installs the pinned static docker CLI when the runner image lacks it, and proves the daemon
+is reachable through the runner's socket mount (`docker info`) — fail early instead of deep
+inside a job that needs containers.
+
+```yaml
+- uses: https://git.madapes.com/actions/better-setup-docker@v1
+```

action.yml

@@ -0,0 +1,29 @@
+name: better-setup-docker
+description: Install the pinned static docker CLI when missing and verify the runner's daemon socket works — for runners that mount the host docker socket.
+inputs:
+  docker-version:
+    description: Exact docker CLI version to install when missing (x.y.z).
+    default: "27.5.1"
+  verify-socket:
+    description: Run `docker info` to prove the daemon socket is reachable ("true"/"false").
+    default: "true"
+runs:
+  using: composite
+  steps:
+    - shell: bash
+      run: |
+        set -euo pipefail
+        v="${{ inputs.docker-version }}"
+        if ! command -v docker >/dev/null 2>&1; then
+          case "$(uname -m)" in
+            x86_64|amd64) arch=x86_64 ;;
+            aarch64|arm64) arch=aarch64 ;;
+            *) echo "better-setup-docker: unsupported arch $(uname -m)" >&2; exit 1 ;;
+          esac
+          curl -fsSL "https://download.docker.com/linux/static/stable/${arch}/docker-${v}.tgz" | tar -xz -C /tmp docker
+          mv /tmp/docker/docker /usr/local/bin/docker
+        fi
+        docker --version
+        if [ "${{ inputs.verify-socket }}" = "true" ]; then
+          docker info >/dev/null && echo "docker ok (host socket)"
+        fi