Proposed feature: Plugable revision deployers

pkg/apis/serving/v1beta1/revision_defaults.go

@@ -84,4 +84,8 @@ func (rs *RevisionSpec) SetDefaults(ctx context.Context) {
 	for i := range vms {
 		vms[i].ReadOnly = true
 	}
+
+	if rs.Deployer.Name == "" {
+		rs.Deployer.Name = "KnativeServing"
+	}
 }

pkg/apis/serving/v1beta1/revision_types.go

@@ -22,6 +22,7 @@ import (
 	"github.com/knative/pkg/kmeta"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"encoding/json"
 )
 
 // +genclient
@@ -127,6 +128,12 @@ type RevisionSpec struct {
 	// be provided.
 	// +optional
 	TimeoutSeconds *int64 `json:"timeoutSeconds,omitempty"`
+
+	// The deployer to handle this revision, used to disable Knatives deploying
+	// of revisions and injection of sidecars, and allow a third party controller
+	// to do it instead.
+	// +optional
+	Deployer Deployer `json:"deployer,omitempty"`
 }
 
 const (
@@ -168,3 +175,17 @@ type RevisionList struct {
 
 	Items []Revision `json:"items"`
 }
+
+// A deployer, to allow a third party controller to deploy revisions.
+type Deployer struct {
+
+	// The name of the deployer. If no deployer is specified, or if the deployer
+	// is KnativeServing, then KnativeServing will deploy it.
+	Name string `json:"name"`
+
+	// Deployer specific configuration, if needed. The structure is specific to
+	// the deployer specified, and it's up to the deployer to do any necessary
+	// validation, updating the status if validation fails.
+	// +optional
+	Config json.RawMessage `json:"config,omitempty"`
+}

pkg/reconciler/revision/reconcile_resources.go

@@ -43,34 +43,44 @@ const (
 )
 
 func (c *Reconciler) reconcileDeployment(ctx context.Context, rev *v1alpha1.Revision) error {
+
 	ns := rev.Namespace
 	deploymentName := resourcenames.Deployment(rev)
 	logger := logging.FromContext(ctx).With(zap.String(logkey.Deployment, deploymentName))
 
 	deployment, err := c.deploymentLister.Deployments(ns).Get(deploymentName)
-	if apierrs.IsNotFound(err) {
-		// Deployment does not exist. Create it.
-		rev.Status.MarkDeploying("Deploying")
-		deployment, err = c.createDeployment(ctx, rev)
-		if err != nil {
-			logger.Errorf("Error creating deployment %q: %v", deploymentName, err)
+
+	if rev.Spec.RevisionSpec.Deployer.Name == "KnativeServing" {
+		if apierrs.IsNotFound(err) {
+			// Deployment does not exist. Create it.
+			rev.Status.MarkDeploying("Deploying")
+			deployment, err = c.createDeployment(ctx, rev)
+			if err != nil {
+				logger.Errorf("Error creating deployment %q: %v", deploymentName, err)
+				return err
+			}
+			logger.Infof("Created deployment %q", deploymentName)
+		} else if err != nil {
+			logger.Errorf("Error reconciling deployment %q: %v", deploymentName, err)
 			return err
+		} else if !metav1.IsControlledBy(deployment, rev) {
+			// Surface an error in the revision's status, and return an error.
+			rev.Status.MarkResourceNotOwned("Deployment", deploymentName)
+			return fmt.Errorf("Revision: %q does not own Deployment: %q", rev.Name, deploymentName)
+		} else {
+			// The deployment exists, but make sure that it has the shape that we expect.
+			deployment, err = c.checkAndUpdateDeployment(ctx, rev, deployment)
+			if err != nil {
+				logger.Errorf("Error updating deployment %q: %v", deploymentName, err)
+				return err
+			}
 		}
-		logger.Infof("Created deployment %q", deploymentName)
-	} else if err != nil {
-		logger.Errorf("Error reconciling deployment %q: %v", deploymentName, err)
-		return err
-	} else if !metav1.IsControlledBy(deployment, rev) {
-		// Surface an error in the revision's status, and return an error.
-		rev.Status.MarkResourceNotOwned("Deployment", deploymentName)
-		return fmt.Errorf("Revision: %q does not own Deployment: %q", rev.Name, deploymentName)
 	} else {
-		// The deployment exists, but make sure that it has the shape that we expect.
-		deployment, err = c.checkAndUpdateDeployment(ctx, rev, deployment)
 		if err != nil {
-			logger.Errorf("Error updating deployment %q: %v", deploymentName, err)
-			return err
+			// There's an error (or it's not found), but we don't care because it's not ours to care about
+			return nil
 		}
+		// Otherwise, continue processing to update the status accordingly.
 	}
 
 	// If a container keeps crashing (no active pods in the deployment although we want some)