[Starlark] Add Starlark-based provisioner backend

 - New provisioner implementation that delegates every
   `pkg/provisioner.Provisioner` method to a named
   function in a user-supplied Starlark script, enabled
   via `--starlark-provisioner-script` CLI arg.

 - The reference script `efi-vmedia.star` that targets
   Ironic redfish-virtualmedia UEFI (custom-deploy or
   qcow2) and rejects unsupported specs.

Signed-off-by: s3rj1k <evasive.gyron@gmail.com>

Author: s3rj1k

go.mod

@@ -15,6 +15,7 @@ require (
 	github.com/prometheus/client_golang v1.23.2
 	github.com/stretchr/testify v1.11.1
 	go.etcd.io/etcd/client/pkg/v3 v3.6.10
+	go.starlark.net v0.0.0-20260326113308-fadfc96def35
 	go.uber.org/zap v1.27.1
 	k8s.io/api v0.35.4
 	k8s.io/apimachinery v0.35.4

go.sum

@@ -185,6 +185,8 @@ go.opentelemetry.io/otel/trace v1.43.0 h1:BkNrHpup+4k4w+ZZ86CZoHHEkohws8AY+WTX09
 go.opentelemetry.io/otel/trace v1.43.0/go.mod h1:/QJhyVBUUswCphDVxq+8mld+AvhXZLhe+8WVFxiFff0=
 go.opentelemetry.io/proto/otlp v1.10.0 h1:IQRWgT5srOCYfiWnpqUYz9CVmbO8bFmKcwYxpuCSL2g=
 go.opentelemetry.io/proto/otlp v1.10.0/go.mod h1:/CV4QoCR/S9yaPj8utp3lvQPoqMtxXdzn7ozvvozVqk=
+go.starlark.net v0.0.0-20260326113308-fadfc96def35 h1:VYAqieSOJNxBDX8KJneTAwvdf4J4zRDE2u+UFXtt9h4=
+go.starlark.net v0.0.0-20260326113308-fadfc96def35/go.mod h1:Iue6g6iirlfLoVi/DYCi5/x0h/bAOuWF3dULTKpt2Vo=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
 go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=

internal/controller/metal3.io/baremetalhost_controller.go

@@ -833,7 +833,7 @@ func (r *BareMetalHostReconciler) registerHost(ctx context.Context, prov provisi
 		dirty = true
 	}
 
-	preprovImgFormats, err := prov.PreprovisioningImageFormats()
+	preprovImgFormats, err := prov.PreprovisioningImageFormats(ctx)
 	if err != nil {
 		return actionError{err}
 	}

internal/controller/metal3.io/host_state_machine_test.go

@@ -1319,7 +1319,7 @@ func (m *mockProvisioner) Register(_ context.Context, _ provisioner.ManagementAc
 	return m.getNextResultByMethod("ValidateManagementAccess"), "", err
 }
 
-func (m *mockProvisioner) PreprovisioningImageFormats() ([]metal3api.ImageFormat, error) {
+func (m *mockProvisioner) PreprovisioningImageFormats(_ context.Context) ([]metal3api.ImageFormat, error) {
 	return nil, nil
 }
 

main.go

@@ -33,6 +33,7 @@ import (
 	"github.com/metal3-io/baremetal-operator/pkg/provisioner/demo"
 	"github.com/metal3-io/baremetal-operator/pkg/provisioner/fixture"
 	"github.com/metal3-io/baremetal-operator/pkg/provisioner/ironic"
+	starlarkprov "github.com/metal3-io/baremetal-operator/pkg/provisioner/starlark"
 	"github.com/metal3-io/baremetal-operator/pkg/secretutils"
 	"github.com/metal3-io/baremetal-operator/pkg/version"
 	ironicv1alpha1 "github.com/metal3-io/ironic-standalone-operator/api/v1alpha1"
@@ -133,6 +134,7 @@ func main() {
 	var devLogging bool
 	var runInTestMode bool
 	var runInDemoMode bool
+	var starlarkScript string
 	var webhookPort int
 	var restConfigQPS float64
 	var restConfigBurst int
@@ -157,6 +159,8 @@ func main() {
 	flag.BoolVar(&runInTestMode, "test-mode", false, "disable ironic communication")
 	flag.BoolVar(&runInDemoMode, "demo-mode", false,
 		"use the demo provisioner to set host states")
+	flag.StringVar(&starlarkScript, "starlark-provisioner-script", os.Getenv("STARLARK_PROVISIONER_SCRIPT"),
+		"path to a Starlark script implementing the provisioner interface")
 	flag.StringVar(&healthAddr, "health-addr", ":9440",
 		"The address the health endpoint binds to.")
 	flag.IntVar(&webhookPort, "webhook-port", 9443, //nolint:mnd
@@ -201,6 +205,23 @@ func main() {
 
 	printVersion()
 
+	// At most one provisioner mode may be selected. Silently picking the
+	// first true mode (the previous behavior) hides a misconfiguration
+	// that would otherwise surface much later as confusing reconcile
+	// behavior. Run this guard before any expensive setup so the operator
+	// fails fast at startup. Enumerating the three pairwise conflicts
+	// covers every "two or more true" combination (the all-three case
+	// matches all three disjuncts).
+	if (runInTestMode && runInDemoMode) ||
+		(runInTestMode && starlarkScript != "") ||
+		(runInDemoMode && starlarkScript != "") {
+		setupLog.Error(nil, "only one provisioner mode may be set",
+			"test-mode", runInTestMode,
+			"demo-mode", runInDemoMode,
+			"starlark-provisioner-script", starlarkScript)
+		os.Exit(1)
+	}
+
 	enableWebhook := webhookPort != 0
 
 	leaderElectionNamespace := os.Getenv("POD_NAMESPACE")
@@ -320,6 +341,13 @@ func main() {
 	} else if runInDemoMode {
 		ctrl.Log.Info("using demo provisioner")
 		provisionerFactory = &demo.Demo{}
+	} else if starlarkScript != "" {
+		ctrl.Log.Info("using starlark provisioner", "script", starlarkScript)
+		provisionerFactory, err = starlarkprov.NewProvisionerFactory(starlarkScript)
+		if err != nil {
+			setupLog.Error(err, "cannot start starlark provisioner")
+			os.Exit(1)
+		}
 	} else {
 		provLog := zap.New(zap.UseFlagOptions(&logOpts)).WithName("provisioner")
 		// Check if we should use Ironic CR integration

pkg/provisioner/demo/demo.go

@@ -111,7 +111,7 @@ func (p *demoProvisioner) Register(_ context.Context, _ provisioner.ManagementAc
 	return
 }
 
-func (p *demoProvisioner) PreprovisioningImageFormats() ([]metal3api.ImageFormat, error) {
+func (p *demoProvisioner) PreprovisioningImageFormats(_ context.Context) ([]metal3api.ImageFormat, error) {
 	return nil, nil
 }
 

pkg/provisioner/fixture/fixture.go

@@ -149,7 +149,7 @@ func (p *fixtureProvisioner) Register(_ context.Context, _ provisioner.Managemen
 	return
 }
 
-func (p *fixtureProvisioner) PreprovisioningImageFormats() ([]metal3api.ImageFormat, error) {
+func (p *fixtureProvisioner) PreprovisioningImageFormats(_ context.Context) ([]metal3api.ImageFormat, error) {
 	return nil, nil
 }
 

pkg/provisioner/ironic/ironic.go

@@ -382,7 +382,7 @@ func (p *ironicProvisioner) configureNode(ctx context.Context, data provisioner.
 // PreprovisioningImageFormats returns a list of acceptable formats for a
 // pre-provisioning image to be built by a PreprovisioningImage object. The
 // list should be nil if no image build is requested.
-func (p *ironicProvisioner) PreprovisioningImageFormats() ([]metal3api.ImageFormat, error) {
+func (p *ironicProvisioner) PreprovisioningImageFormats(_ context.Context) ([]metal3api.ImageFormat, error) {
 	if !p.config.havePreprovImgBuilder {
 		return nil, nil
 	}

pkg/provisioner/ironic/register_test.go

@@ -1,6 +1,7 @@
 package ironic
 
 import (
+	"context"
 	"net/http"
 	"testing"
 
@@ -964,7 +965,7 @@ func TestPreprovisioningImageFormats(t *testing.T) {
 			prov, _ := newProvisionerWithSettings(host, bmc.Credentials{}, nil, ironicEndpoint, auth)
 			prov.config.havePreprovImgBuilder = tc.PreprovImgEnabled
 
-			fmts, err := prov.PreprovisioningImageFormats()
+			fmts, err := prov.PreprovisioningImageFormats(context.Background())
 
 			require.NoError(t, err)
 			assert.Equal(t, tc.Expected, fmts)

pkg/provisioner/provisioner.go

@@ -147,7 +147,7 @@ type Provisioner interface {
 	// PreprovisioningImageFormats returns a list of acceptable formats for a
 	// pre-provisioning image to be built by a PreprovisioningImage object. The
 	// list should be nil if no image build is requested.
-	PreprovisioningImageFormats() ([]metal3api.ImageFormat, error)
+	PreprovisioningImageFormats(ctx context.Context) ([]metal3api.ImageFormat, error)
 
 	// InspectHardware updates the HardwareDetails field of the host with
 	// details of devices discovered on the hardware. It may be called