translator: make edgelb pool name optional

docs/usage/10-provisioning-services.adoc

@@ -29,17 +29,21 @@ In particular, exposing UDP or SCTP services is **NOT** supported.
 === Using `dklb` to provision a Kubernetes service
 
 To expose a TCP application running on MKE to either inside or outside the DC/OS cluster, a Kubernetes https://kubernetes.io/docs/concepts/services-networking/service/[`Service`] resource of type https://kubernetes.io/docs/concepts/services-networking/service/#loadbalancer[`LoadBalancer`] must be created.
-Furthermore, and in order for `dklb` to provision said service using EdgeLB, the service must be https://kubernetes.io/docs/concepts/overview/working-with-objects/annotations/[annotated] with the following annotation:
+`dklb` will react to this event by provisioning an EdgeLB pool (henceforth referred to as the _target EdgeLB pool_) for the `Service` resource based on its specification.
+
+=== Customizing the name of the EdgeLB pool
+
+By default, `dklb` uses the MKE cluster's name and the `Service` resource's namespace and name to compute the name of the target EdgeLB pool.
+To specify a custom name for said EdgeLB pool, one may https://kubernetes.io/docs/concepts/overview/working-with-objects/annotations/[annotate] the `Service` resource with the following annotation:
 
 [source,text]
 ----
 kubernetes.dcos.io/edgelb-pool-name: "<edgelb-pool-name>"
 ----
 
-This annotation lets `dklb` know about the EdgeLB pool it should use to provision the service (henceforth referred to as the _target EdgeLB pool_).
-Depending on whether the target EdgeLB pool exists or not, `dklb` will create or update it in order to expose all ports defined in the `Service` resource.
+Depending on whether the "<edgelb-pool-name>" EdgeLB pool exists or not, `dklb` will create or update it in order to expose all ports defined in the `Service` resource.
 
-IMPORTANT: One must not remove or change the value of this annotation at any time after the `Service` resource is created.
+IMPORTANT: One must not remove or change the value of this annotation at any time after it is added to a given `Service` resource.
 
 === Intra-DC/OS vs external exposure
 

pkg/controllers/ingress.go

@@ -126,7 +126,7 @@ func (c *IngressController) processQueueItem(workItem WorkItem) error {
 	er := kubernetesutil.NewEventRecorderForNamespace(c.kubeClient, ingress.Namespace)
 
 	// Compute the set of options that will be used to translate the Ingress resource into an EdgeLB pool.
-	options, err := translator.ComputeIngressTranslationOptions(ingress)
+	options, err := translator.ComputeIngressTranslationOptions(c.clusterName, ingress)
 	if err != nil {
 		// Emit an event and log an error, but do not re-enqueue as the resource's spec was found to be invalid.
 		er.Eventf(ingress, corev1.EventTypeWarning, constants.ReasonInvalidAnnotations, "the resource's annotations are not valid: %v", err)

pkg/controllers/service.go

@@ -133,7 +133,7 @@ func (c *ServiceController) processQueueItem(workItem WorkItem) error {
 	er := kubernetesutil.NewEventRecorderForNamespace(c.kubeClient, service.Namespace)
 
 	// Compute the set of options that will be used to translate the Service resource into an EdgeLB pool.
-	options, err := translator.ComputeServiceTranslationOptions(service)
+	options, err := translator.ComputeServiceTranslationOptions(c.clusterName, service)
 	if err != nil {
 		// Emit an event and log an error, but do not re-enqueue as the resource's spec was found to be invalid.
 		er.Eventf(service, corev1.EventTypeWarning, constants.ReasonInvalidAnnotations, "the resource's annotations are not valid: %v", err)

pkg/translator/base_options.go

@@ -31,17 +31,16 @@ type BaseTranslationOptions struct {
 
 // parseBaseTranslationOptions attempts to compute base, common translation options from the specified set of annotations.
 // In case options cannot be computed or are invalid, the error message MUST be suitable to be used as the message for a Kubernetes event associated with the resource.
-func parseBaseTranslationOptions(annotations map[string]string) (*BaseTranslationOptions, error) {
+func parseBaseTranslationOptions(clusterName, namespace, name string, annotations map[string]string) (*BaseTranslationOptions, error) {
 	// Create a "BaseTranslationOptions" struct to hold the computed options.
 	res := &BaseTranslationOptions{}
 
-	// Parse the name of the target EdgeLB pool.
-	// This annotation is MANDATORY.
-	v, exists := annotations[constants.EdgeLBPoolNameAnnotationKey]
-	if !exists || v == "" {
-		return nil, fmt.Errorf("required annotation %q has not been provided", constants.EdgeLBPoolNameAnnotationKey)
+	// Parse or compute the name of the target EdgeLB pool.
+	if v, exists := annotations[constants.EdgeLBPoolNameAnnotationKey]; !exists || v == "" {
+		res.EdgeLBPoolName = computeEdgeLBPoolName(clusterName, namespace, name)
+	} else {
+		res.EdgeLBPoolName = v
 	}
-	res.EdgeLBPoolName = v
 
 	// Parse the role of the target EdgeLB pool.
 	if v, exists := annotations[constants.EdgeLBPoolRoleAnnotationKey]; !exists || v == "" {

pkg/translator/base_options_utils.go

@@ -0,0 +1,21 @@
+package translator
+
+import (
+	"fmt"
+
+	"github.com/mesosphere/dklb/pkg/util/strings"
+)
+
+const (
+	// edgeLBPoolNameComponentSeparator is the string used as to separate the components of an EdgeLB pool's name.
+	// "--" is chosen as the value since the name of an EdgeLB pool must match the "^[a-z0-9]([a-z0-9-]*[a-z0-9])?$" regular expression.
+	edgeLBPoolNameComponentSeparator = "--"
+	// edgeLBPoolNameFormatString is the format string used to compute the name of an EdgeLB pool corresponding to a given Kubernetes resource.
+	// The resulting name is of the form "<cluster-name>--<namespace>--<name>".
+	edgeLBPoolNameFormatString = "%s" + edgeLBPoolNameComponentSeparator + "%s" + edgeLBPoolNameComponentSeparator + "%s"
+)
+
+// computeEdgeLBPoolName computes the name of the EdgeLB pool that corresponds to the Kubernetes resource corresponding to the provided coordinates.
+func computeEdgeLBPoolName(clusterName, namespace, name string) string {
+	return fmt.Sprintf(edgeLBPoolNameFormatString, strings.ReplaceForwardSlashes(clusterName, edgeLBPoolNameComponentSeparator), namespace, name)
+}

pkg/translator/ingress_options.go

@@ -19,7 +19,7 @@ type IngressTranslationOptions struct {
 
 // ComputeIngressTranslationOptions computes the set of options to use for "translating" the specified Ingress resource into an EdgeLB pool.
 // In case options cannot be computed or are invalid, the error message MUST be suitable to be used as the message for a Kubernetes event associated with the resource.
-func ComputeIngressTranslationOptions(obj *extsv1beta1.Ingress) (*IngressTranslationOptions, error) {
+func ComputeIngressTranslationOptions(clusterName string, obj *extsv1beta1.Ingress) (*IngressTranslationOptions, error) {
 	// Create an "IngressTranslationOptions" struct to hold the computed options.
 	res := &IngressTranslationOptions{}
 	var annotations map[string]string
@@ -33,7 +33,7 @@ func ComputeIngressTranslationOptions(obj *extsv1beta1.Ingress) (*IngressTransla
 	}
 
 	// Parse base translation options.
-	b, err := parseBaseTranslationOptions(annotations)
+	b, err := parseBaseTranslationOptions(clusterName, obj.Namespace, obj.Name, annotations)
 	if err != nil {
 		return nil, err
 	}

pkg/translator/ingress_options_test.go

@@ -20,18 +20,28 @@ func TestComputeIngressTranslationOptions(t *testing.T) {
 		options     *translator.IngressTranslationOptions
 		error       error
 	}{
-		// Test computing options for an Ingress resource without the required annotations.
-		// Make sure an error is returned.
+		// Test computing options for an Ingress resource without any annotations.
+		// Make sure the name of the EdgeLB pool is computed as expected, and that the default values are used everywhere else.
 		{
-			description: "compute options for an Ingress resource without the required annotations",
+			description: "compute options for an Ingress resource without any annotations",
 			annotations: map[string]string{},
-			options:     nil,
-			error:       fmt.Errorf("required annotation %q has not been provided", constants.EdgeLBPoolNameAnnotationKey),
+			options: &translator.IngressTranslationOptions{
+				BaseTranslationOptions: translator.BaseTranslationOptions{
+					EdgeLBPoolName:             "dev--kubernetes01--foo--bar",
+					EdgeLBPoolRole:             translator.DefaultEdgeLBPoolRole,
+					EdgeLBPoolCpus:             translator.DefaultEdgeLBPoolCpus,
+					EdgeLBPoolMem:              translator.DefaultEdgeLBPoolMem,
+					EdgeLBPoolSize:             translator.DefaultEdgeLBPoolSize,
+					EdgeLBPoolCreationStrategy: translator.DefaultEdgeLBPoolCreationStrategy,
+				},
+				EdgeLBPoolPort: translator.DefaultEdgeLBPoolPort,
+			},
+			error: nil,
 		},
-		// Test computing options for an Ingress resource with just the required annotations.
+		// Test computing options for an Ingress resource specifying the name of the target EdgeLB pool.
 		// Make sure the name of the EdgeLB pool is captured as expected, and that the default values are used everywhere else.
 		{
-			description: "compute options for an Ingress resource with just the required annotations",
+			description: "compute options for an Ingress resource specifying the name of the target EdgeLB pool",
 			annotations: map[string]string{
 				constants.EdgeLBPoolNameAnnotationKey: "foo",
 			},
@@ -49,16 +59,15 @@ func TestComputeIngressTranslationOptions(t *testing.T) {
 			error: nil,
 		},
 		// Test computing options for an Ingress resource defining a custom frontend bind port.
-		// Make sure the name of the EdgeLB pool and the frontend bind port are captured as expected, and that the default values are used everywhere else.
+		// Make sure the frontend bind port is captured as expected, and that the default values are used everywhere else.
 		{
 			description: "compute options for an Ingress resource defining a custom frontend bind port",
 			annotations: map[string]string{
-				constants.EdgeLBPoolNameAnnotationKey: "foo",
-				constants.EdgeLBPoolPortKey:           "14708",
+				constants.EdgeLBPoolPortKey: "14708",
 			},
 			options: &translator.IngressTranslationOptions{
 				BaseTranslationOptions: translator.BaseTranslationOptions{
-					EdgeLBPoolName:             "foo",
+					EdgeLBPoolName:             "dev--kubernetes01--foo--bar",
 					EdgeLBPoolRole:             translator.DefaultEdgeLBPoolRole,
 					EdgeLBPoolCpus:             translator.DefaultEdgeLBPoolCpus,
 					EdgeLBPoolMem:              translator.DefaultEdgeLBPoolMem,
@@ -74,8 +83,7 @@ func TestComputeIngressTranslationOptions(t *testing.T) {
 		{
 			description: "compute options for an Ingress resource defining an invalid value for the frontend bind port",
 			annotations: map[string]string{
-				constants.EdgeLBPoolNameAnnotationKey: "foo",
-				constants.EdgeLBPoolPortKey:           "74511",
+				constants.EdgeLBPoolPortKey: "74511",
 			},
 			options: nil,
 			error:   fmt.Errorf("%d is not a valid port number", 74511),
@@ -113,8 +121,7 @@ func TestComputeIngressTranslationOptions(t *testing.T) {
 		{
 			description: "compute options for an Ingress resource with a custom but invalid port mapping",
 			annotations: map[string]string{
-				constants.EdgeLBPoolNameAnnotationKey: "foo",
-				constants.EdgeLBPoolPortKey:           "74511",
+				constants.EdgeLBPoolPortKey: "74511",
 			},
 			options: nil,
 			error:   fmt.Errorf("%d is not a valid port number", 74511),
@@ -124,8 +131,7 @@ func TestComputeIngressTranslationOptions(t *testing.T) {
 		{
 			description: "compute options for a Service resource having an invalid port mapping",
 			annotations: map[string]string{
-				constants.EdgeLBPoolNameAnnotationKey: "foo",
-				constants.EdgeLBPoolPortKey:           "foo",
+				constants.EdgeLBPoolPortKey: "foo",
 			},
 			options: nil,
 			error:   fmt.Errorf("failed to parse %q as the frontend bind port to use: %v", "foo", "strconv.Atoi: parsing \"foo\": invalid syntax"),
@@ -137,7 +143,7 @@ func TestComputeIngressTranslationOptions(t *testing.T) {
 		// Create a dummy Ingress resource containing the annotations for the current test.
 		r := ingresstestutil.DummyIngressResource("foo", "bar", ingresstestutil.WithAnnotations(test.annotations))
 		// Compute the translation options for the resource.
-		o, err := translator.ComputeIngressTranslationOptions(r)
+		o, err := translator.ComputeIngressTranslationOptions(testClusterName, r)
 		if err != nil {
 			// Make sure the error matches the expected one.
 			assert.EqualError(t, err, test.error.Error())

pkg/translator/service_options.go

@@ -19,7 +19,7 @@ type ServiceTranslationOptions struct {
 
 // ComputeServiceTranslationOptions computes the set of options to use for "translating" the specified Service resource into an EdgeLB pool.
 // In case options cannot be computed or are invalid, the error message MUST be suitable to be used as the message for a Kubernetes event associated with the resource.
-func ComputeServiceTranslationOptions(obj *corev1.Service) (*ServiceTranslationOptions, error) {
+func ComputeServiceTranslationOptions(clusterName string, obj *corev1.Service) (*ServiceTranslationOptions, error) {
 	// Create an "ServiceTranslationOptions" struct to hold the computed options.
 	res := &ServiceTranslationOptions{
 		EdgeLBPoolPortMap: make(map[int32]int32, len(obj.Spec.Ports)),
@@ -35,7 +35,7 @@ func ComputeServiceTranslationOptions(obj *corev1.Service) (*ServiceTranslationO
 	}
 
 	// Parse base translation options.
-	b, err := parseBaseTranslationOptions(annotations)
+	b, err := parseBaseTranslationOptions(clusterName, obj.Namespace, obj.Name, annotations)
 	if err != nil {
 		return nil, err
 	}