enhance: add macOS VM executor backend

Replace the Tart-based prototype with a runner-oriented macOS VM
executor backed by runner-executor-macos and Apple Virtualization.

Assisted-by: Codet:MODEL_VERSION

internal/pkg/config/config.example.yaml

@@ -92,7 +92,8 @@ runner:
   # at the price of the stock artifact actions refusing and the cache client keeping to v1.
   #patch_actions: true
   # The labels of a runner are used to determine which jobs the runner can run, and how to run them.
-  # Like: "macos-arm64:host" or "ubuntu-latest:docker://docker.gitea.com/runner-images:ubuntu-latest"
+  # Like: "macos-arm64:host", "ubuntu-latest:docker://docker.gitea.com/runner-images:ubuntu-latest",
+  # or "macos-latest:macos-vm://ghcr.io/cirruslabs/macos-sonoma-base:latest"
   # Find more images provided by Gitea at https://gitea.com/gitea/runner-images .
   # If it's empty when registering, it will ask for inputting labels.
   # If it's empty when execute `daemon`, will use labels in `.runner` file.
@@ -271,6 +272,19 @@ host:
   # If it's empty, $HOME/.cache/act/ will be used.
   #workdir_parent:
 
+macos_vm:
+  # Path to the runner-executor-macos binary. Empty uses PATH lookup.
+  #executor_path: runner-executor-macos
+  # The guest directory under which the job workspace is created. The VM must run
+  # as a user that can write there.
+  #workdir_parent: /Users/admin/runner
+  # Number of virtual CPUs. Omit or set to 0 to keep the image default.
+  #cpu: 0
+  # VM memory in megabytes. Omit or set to 0 to keep the image default.
+  #memory: 0
+  # How long to wait for the VM to become ready after it starts.
+  #boot_timeout: 5m
+
 # Optional local task-admission checks. Disabled by default. When enabled, low
 # disk space or a failing script pauses new task fetching; existing jobs continue.
 # No health checks run while any job is active; the last result is reused until idle.

internal/pkg/config/config.go

@@ -179,6 +179,15 @@ type Host struct {
 	WorkdirParent string `yaml:"workdir_parent"` // WorkdirParent specifies the parent directory for the host's working directory.
 }
 
+// MacOSVM represents the configuration for the macOS VM executor.
+type MacOSVM struct {
+	ExecutorPath  string        `yaml:"executor_path"`  // ExecutorPath is the runner-executor-macos binary to invoke.
+	WorkdirParent string        `yaml:"workdir_parent"` // WorkdirParent is the guest directory under which the job workspace is created.
+	CPU           int           `yaml:"cpu"`            // CPU is the number of virtual CPUs. Zero keeps the image default.
+	Memory        int           `yaml:"memory"`         // Memory is the VM memory in megabytes. Zero keeps the image default.
+	BootTimeout   time.Duration `yaml:"boot_timeout"`   // BootTimeout bounds how long to wait for the VM to become ready.
+}
+
 // Metrics represents the configuration for the Prometheus metrics endpoint.
 type Metrics struct {
 	Enabled        bool          `yaml:"enabled"`         // Enabled indicates whether the metrics endpoint is exposed.
@@ -203,6 +212,7 @@ type Config struct {
 	Cache       Cache       `yaml:"cache"`        // Cache represents the configuration for caching.
 	Container   Container   `yaml:"container"`    // Container represents the configuration for the container.
 	Host        Host        `yaml:"host"`         // Host represents the configuration for the host.
+	MacOSVM     MacOSVM     `yaml:"macos_vm"`     // MacOSVM represents the configuration for the macOS VM executor.
 	Metrics     Metrics     `yaml:"metrics"`      // Metrics represents the configuration for the Prometheus metrics endpoint.
 	HealthCheck HealthCheck `yaml:"health_check"` // HealthCheck controls opt-in local task-admission checks.
 }
@@ -300,6 +310,15 @@ func LoadDefault(file string) (*Config, error) {
 		}
 		cfg.Host.WorkdirParent = filepath.Join(home, ".cache", "act")
 	}
+	if cfg.MacOSVM.ExecutorPath == "" {
+		cfg.MacOSVM.ExecutorPath = "runner-executor-macos"
+	}
+	if cfg.MacOSVM.WorkdirParent == "" {
+		cfg.MacOSVM.WorkdirParent = "/Users/admin/runner"
+	}
+	if cfg.MacOSVM.BootTimeout <= 0 {
+		cfg.MacOSVM.BootTimeout = 5 * time.Minute
+	}
 	if cfg.Runner.FetchTimeout <= 0 {
 		cfg.Runner.FetchTimeout = 5 * time.Second
 	}

internal/pkg/config/config_test.go

@@ -67,6 +67,31 @@ func TestLoadDefault_DefaultsWorkdirCleanupAge(t *testing.T) {
 	assert.Equal(t, DefaultImage, cfg.Runner.DefaultImage)
 }
 
+func TestLoadDefault_MacOSVMDefaults(t *testing.T) {
+	cfg, err := LoadDefault("")
+	require.NoError(t, err)
+	assert.Equal(t, "runner-executor-macos", cfg.MacOSVM.ExecutorPath)
+	assert.Equal(t, "/Users/admin/runner", cfg.MacOSVM.WorkdirParent)
+	assert.Equal(t, 5*time.Minute, cfg.MacOSVM.BootTimeout)
+
+	path := filepath.Join(t.TempDir(), "config.yaml")
+	require.NoError(t, os.WriteFile(path, []byte(`
+macos_vm:
+  executor_path: /usr/local/bin/runner-executor-macos
+  workdir_parent: /Users/runner
+  cpu: 4
+  memory: 8192
+  boot_timeout: 3m
+`), 0o600))
+	cfg, err = LoadDefault(path)
+	require.NoError(t, err)
+	assert.Equal(t, "/usr/local/bin/runner-executor-macos", cfg.MacOSVM.ExecutorPath)
+	assert.Equal(t, "/Users/runner", cfg.MacOSVM.WorkdirParent)
+	assert.Equal(t, 4, cfg.MacOSVM.CPU)
+	assert.Equal(t, 8192, cfg.MacOSVM.Memory)
+	assert.Equal(t, 3*time.Minute, cfg.MacOSVM.BootTimeout)
+}
+
 func TestLoadDefault_HealthChecksAreOptIn(t *testing.T) {
 	cfg, err := LoadDefault("")
 	require.NoError(t, err)