k8s: Support discovery of ingresses (#3111)

* k8s: Support discovery of ingresses

* Move additional labels below allocation

This makes it more obvious why the additional elements are allocated.
Also fix allocation for node where we only set a single label.

* k8s: Remove port from ingress discovery

* k8s: Add comment to ingress discovery example

config/config.go

@@ -1005,10 +1005,11 @@ type KubernetesRole string
 
 // The valid options for KubernetesRole.
 const (
-	KubernetesRoleNode     = "node"
-	KubernetesRolePod      = "pod"
-	KubernetesRoleService  = "service"
-	KubernetesRoleEndpoint = "endpoints"
+	KubernetesRoleNode     KubernetesRole = "node"
+	KubernetesRolePod      KubernetesRole = "pod"
+	KubernetesRoleService  KubernetesRole = "service"
+	KubernetesRoleEndpoint KubernetesRole = "endpoints"
+	KubernetesRoleIngress  KubernetesRole = "ingress"
 )
 
 // UnmarshalYAML implements the yaml.Unmarshaler interface.
@@ -1017,7 +1018,7 @@ func (c *KubernetesRole) UnmarshalYAML(unmarshal func(interface{}) error) error
 		return err
 	}
 	switch *c {
-	case KubernetesRoleNode, KubernetesRolePod, KubernetesRoleService, KubernetesRoleEndpoint:
+	case KubernetesRoleNode, KubernetesRolePod, KubernetesRoleService, KubernetesRoleEndpoint, KubernetesRoleIngress:
 		return nil
 	default:
 		return fmt.Errorf("Unknown Kubernetes SD role %q", *c)

discovery/kubernetes/endpoints.go

@@ -154,8 +154,11 @@ func (e *Endpoints) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 }
 
 func convertToEndpoints(o interface{}) (*apiv1.Endpoints, error) {
-	endpoints, isEndpoints := o.(*apiv1.Endpoints)
-	if !isEndpoints {
+	endpoints, ok := o.(*apiv1.Endpoints)
+	if ok {
+		return endpoints, nil
+	}
+
 	deletedState, ok := o.(cache.DeletedFinalStateUnknown)
 	if !ok {
 		return nil, fmt.Errorf("Received unexpected object: %v", o)
@@ -164,8 +167,6 @@ func convertToEndpoints(o interface{}) (*apiv1.Endpoints, error) {
 	if !ok {
 		return nil, fmt.Errorf("DeletedFinalStateUnknown contained non-Endpoints object: %v", deletedState.Obj)
 	}
-	}
-
 	return endpoints, nil
 }
 

discovery/kubernetes/ingress.go

@@ -0,0 +1,184 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package kubernetes
+
+import (
+	"fmt"
+
+	"github.com/prometheus/common/log"
+	"github.com/prometheus/common/model"
+	"github.com/prometheus/prometheus/config"
+	"github.com/prometheus/prometheus/util/strutil"
+	"golang.org/x/net/context"
+	"k8s.io/client-go/pkg/apis/extensions/v1beta1"
+	"k8s.io/client-go/tools/cache"
+)
+
+// Ingress implements discovery of Kubernetes ingresss.
+type Ingress struct {
+	logger   log.Logger
+	informer cache.SharedInformer
+	store    cache.Store
+}
+
+// NewIngress returns a new ingress discovery.
+func NewIngress(l log.Logger, inf cache.SharedInformer) *Ingress {
+	return &Ingress{logger: l, informer: inf, store: inf.GetStore()}
+}
+
+// Run implements the TargetProvider interface.
+func (s *Ingress) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
+	// Send full initial set of pod targets.
+	var initial []*config.TargetGroup
+	for _, o := range s.store.List() {
+		tg := s.buildIngress(o.(*v1beta1.Ingress))
+		initial = append(initial, tg)
+	}
+	select {
+	case <-ctx.Done():
+		return
+	case ch <- initial:
+	}
+
+	// Send target groups for ingress updates.
+	send := func(tg *config.TargetGroup) {
+		select {
+		case <-ctx.Done():
+		case ch <- []*config.TargetGroup{tg}:
+		}
+	}
+	s.informer.AddEventHandler(cache.ResourceEventHandlerFuncs{
+		AddFunc: func(o interface{}) {
+			eventCount.WithLabelValues("ingress", "add").Inc()
+
+			ingress, err := convertToIngress(o)
+			if err != nil {
+				s.logger.With("err", err).Errorln("converting to Ingress object failed")
+				return
+			}
+			send(s.buildIngress(ingress))
+		},
+		DeleteFunc: func(o interface{}) {
+			eventCount.WithLabelValues("ingress", "delete").Inc()
+
+			ingress, err := convertToIngress(o)
+			if err != nil {
+				s.logger.With("err", err).Errorln("converting to Ingress object failed")
+				return
+			}
+			send(&config.TargetGroup{Source: ingressSource(ingress)})
+		},
+		UpdateFunc: func(_, o interface{}) {
+			eventCount.WithLabelValues("ingress", "update").Inc()
+
+			ingress, err := convertToIngress(o)
+			if err != nil {
+				s.logger.With("err", err).Errorln("converting to Ingress object failed")
+				return
+			}
+			send(s.buildIngress(ingress))
+		},
+	})
+
+	// Block until the target provider is explicitly canceled.
+	<-ctx.Done()
+}
+
+func convertToIngress(o interface{}) (*v1beta1.Ingress, error) {
+	ingress, ok := o.(*v1beta1.Ingress)
+	if ok {
+		return ingress, nil
+	}
+
+	deletedState, ok := o.(cache.DeletedFinalStateUnknown)
+	if !ok {
+		return nil, fmt.Errorf("Received unexpected object: %v", o)
+	}
+	ingress, ok = deletedState.Obj.(*v1beta1.Ingress)
+	if !ok {
+		return nil, fmt.Errorf("DeletedFinalStateUnknown contained non-Ingress object: %v", deletedState.Obj)
+	}
+	return ingress, nil
+}
+
+func ingressSource(s *v1beta1.Ingress) string {
+	return "ingress/" + s.Namespace + "/" + s.Name
+}
+
+const (
+	ingressNameLabel        = metaLabelPrefix + "ingress_name"
+	ingressLabelPrefix      = metaLabelPrefix + "ingress_label_"
+	ingressAnnotationPrefix = metaLabelPrefix + "ingress_annotation_"
+	ingressSchemeLabel      = metaLabelPrefix + "ingress_scheme"
+	ingressHostLabel        = metaLabelPrefix + "ingress_host"
+	ingressPathLabel        = metaLabelPrefix + "ingress_path"
+)
+
+func ingressLabels(ingress *v1beta1.Ingress) model.LabelSet {
+	ls := make(model.LabelSet, len(ingress.Labels)+len(ingress.Annotations)+2)
+	ls[ingressNameLabel] = lv(ingress.Name)
+	ls[namespaceLabel] = lv(ingress.Namespace)
+
+	for k, v := range ingress.Labels {
+		ln := strutil.SanitizeLabelName(ingressLabelPrefix + k)
+		ls[model.LabelName(ln)] = lv(v)
+	}
+
+	for k, v := range ingress.Annotations {
+		ln := strutil.SanitizeLabelName(ingressAnnotationPrefix + k)
+		ls[model.LabelName(ln)] = lv(v)
+	}
+	return ls
+}
+
+func pathsFromIngressRule(rv *v1beta1.IngressRuleValue) []string {
+	if rv.HTTP == nil {
+		return []string{"/"}
+	}
+	paths := make([]string, len(rv.HTTP.Paths))
+	for n, p := range rv.HTTP.Paths {
+		path := p.Path
+		if path == "" {
+			path = "/"
+		}
+		paths[n] = path
+	}
+	return paths
+}
+
+func (s *Ingress) buildIngress(ingress *v1beta1.Ingress) *config.TargetGroup {
+	tg := &config.TargetGroup{
+		Source: ingressSource(ingress),
+	}
+	tg.Labels = ingressLabels(ingress)
+
+	schema := "http"
+	if ingress.Spec.TLS != nil {
+		schema = "https"
+	}
+	for _, rule := range ingress.Spec.Rules {
+		paths := pathsFromIngressRule(&rule.IngressRuleValue)
+
+		for _, path := range paths {
+			tg.Targets = append(tg.Targets, model.LabelSet{
+				model.AddressLabel: lv(rule.Host),
+				ingressSchemeLabel: lv(schema),
+				ingressHostLabel:   lv(rule.Host),
+				ingressPathLabel:   lv(path),
+			})
+		}
+	}
+
+	return tg
+}

discovery/kubernetes/ingress_test.go

@@ -0,0 +1,137 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package kubernetes
+
+import (
+	"testing"
+
+	"github.com/prometheus/common/log"
+	"github.com/prometheus/common/model"
+	"github.com/prometheus/prometheus/config"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/pkg/apis/extensions/v1beta1"
+)
+
+func ingressStoreKeyFunc(obj interface{}) (string, error) {
+	return obj.(*v1beta1.Ingress).ObjectMeta.Name, nil
+}
+
+func newFakeIngressInformer() *fakeInformer {
+	return newFakeInformer(ingressStoreKeyFunc)
+}
+
+func makeTestIngressDiscovery() (*Ingress, *fakeInformer) {
+	i := newFakeIngressInformer()
+	return NewIngress(log.Base(), i), i
+}
+
+func makeIngress(tls []v1beta1.IngressTLS) *v1beta1.Ingress {
+	return &v1beta1.Ingress{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:        "testingress",
+			Namespace:   "default",
+			Labels:      map[string]string{"testlabel": "testvalue"},
+			Annotations: map[string]string{"testannotation": "testannotationvalue"},
+		},
+		Spec: v1beta1.IngressSpec{
+			TLS: tls,
+			Rules: []v1beta1.IngressRule{
+				{
+					Host: "example.com",
+					IngressRuleValue: v1beta1.IngressRuleValue{
+						HTTP: &v1beta1.HTTPIngressRuleValue{
+							Paths: []v1beta1.HTTPIngressPath{
+								{Path: "/"},
+								{Path: "/foo"},
+							},
+						},
+					},
+				},
+				{
+					// No backend config, ignored
+					Host: "nobackend.example.com",
+					IngressRuleValue: v1beta1.IngressRuleValue{
+						HTTP: &v1beta1.HTTPIngressRuleValue{},
+					},
+				},
+				{
+					Host: "test.example.com",
+					IngressRuleValue: v1beta1.IngressRuleValue{
+						HTTP: &v1beta1.HTTPIngressRuleValue{
+							Paths: []v1beta1.HTTPIngressPath{{}},
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
+func expectedTargetGroups(tls bool) []*config.TargetGroup {
+	scheme := "http"
+	if tls {
+		scheme = "https"
+	}
+	return []*config.TargetGroup{
+		{
+			Targets: []model.LabelSet{
+				{
+					"__meta_kubernetes_ingress_scheme": lv(scheme),
+					"__meta_kubernetes_ingress_host":   "example.com",
+					"__meta_kubernetes_ingress_path":   "/",
+					"__address__":                      "example.com",
+				},
+				{
+					"__meta_kubernetes_ingress_scheme": lv(scheme),
+					"__meta_kubernetes_ingress_host":   "example.com",
+					"__meta_kubernetes_ingress_path":   "/foo",
+					"__address__":                      "example.com",
+				},
+				{
+					"__meta_kubernetes_ingress_scheme": lv(scheme),
+					"__meta_kubernetes_ingress_host":   "test.example.com",
+					"__address__":                      "test.example.com",
+					"__meta_kubernetes_ingress_path":   "/",
+				},
+			},
+			Labels: model.LabelSet{
+				"__meta_kubernetes_ingress_name":                      "testingress",
+				"__meta_kubernetes_namespace":                         "default",
+				"__meta_kubernetes_ingress_label_testlabel":           "testvalue",
+				"__meta_kubernetes_ingress_annotation_testannotation": "testannotationvalue",
+			},
+			Source: "ingress/default/testingress",
+		},
+	}
+}
+
+func TestIngressDiscoveryInitial(t *testing.T) {
+	n, i := makeTestIngressDiscovery()
+	i.GetStore().Add(makeIngress(nil))
+
+	k8sDiscoveryTest{
+		discovery:       n,
+		expectedInitial: expectedTargetGroups(false),
+	}.Run(t)
+}
+
+func TestIngressDiscoveryInitialTLS(t *testing.T) {
+	n, i := makeTestIngressDiscovery()
+	i.GetStore().Add(makeIngress([]v1beta1.IngressTLS{{}}))
+
+	k8sDiscoveryTest{
+		discovery:       n,
+		expectedInitial: expectedTargetGroups(true),
+	}.Run(t)
+}

discovery/kubernetes/kubernetes.go

@@ -28,6 +28,7 @@ import (
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/pkg/api"
 	apiv1 "k8s.io/client-go/pkg/api/v1"
+	"k8s.io/client-go/pkg/apis/extensions"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/cache"
 )
@@ -159,6 +160,7 @@ const resyncPeriod = 10 * time.Minute
 // Run implements the TargetProvider interface.
 func (d *Discovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 	rclient := d.client.Core().RESTClient()
+	reclient := d.client.Extensions().RESTClient()
 
 	namespaces := d.getNamespaces()
 
@@ -236,6 +238,26 @@ func (d *Discovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 			}()
 		}
 		wg.Wait()
+	case "ingress":
+		var wg sync.WaitGroup
+		for _, namespace := range namespaces {
+			ilw := cache.NewListWatchFromClient(reclient, "ingresses", namespace, nil)
+			ingress := NewIngress(
+				d.logger.With("kubernetes_sd", "ingress"),
+				cache.NewSharedInformer(ilw, &extensions.Ingress{}, resyncPeriod),
+			)
+			go ingress.informer.Run(ctx.Done())
+
+			for !ingress.informer.HasSynced() {
+				time.Sleep(100 * time.Millisecond)
+			}
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				ingress.Run(ctx, ch)
+			}()
+		}
+		wg.Wait()
 	case "node":
 		nlw := cache.NewListWatchFromClient(rclient, "nodes", api.NamespaceAll, nil)
 		node := NewNode(

discovery/kubernetes/node.go

@@ -99,8 +99,11 @@ func (n *Node) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 }
 
 func convertToNode(o interface{}) (*apiv1.Node, error) {
-	node, isNode := o.(*apiv1.Node)
-	if !isNode {
+	node, ok := o.(*apiv1.Node)
+	if ok {
+		return node, nil
+	}
+
 	deletedState, ok := o.(cache.DeletedFinalStateUnknown)
 	if !ok {
 		return nil, fmt.Errorf("Received unexpected object: %v", o)
@@ -109,8 +112,6 @@ func convertToNode(o interface{}) (*apiv1.Node, error) {
 	if !ok {
 		return nil, fmt.Errorf("DeletedFinalStateUnknown contained non-Node object: %v", deletedState.Obj)
 	}
-	}
-
 	return node, nil
 }
 
@@ -126,7 +127,7 @@ const (
 )
 
 func nodeLabels(n *apiv1.Node) model.LabelSet {
-	ls := make(model.LabelSet, len(n.Labels)+len(n.Annotations)+2)
+	ls := make(model.LabelSet, len(n.Labels)+len(n.Annotations)+1)
 
 	ls[nodeNameLabel] = lv(n.Name)
 

discovery/kubernetes/pod.go

@@ -107,8 +107,11 @@ func (p *Pod) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 }
 
 func convertToPod(o interface{}) (*apiv1.Pod, error) {
-	pod, isPod := o.(*apiv1.Pod)
-	if !isPod {
+	pod, ok := o.(*apiv1.Pod)
+	if ok {
+		return pod, nil
+	}
+
 	deletedState, ok := o.(cache.DeletedFinalStateUnknown)
 	if !ok {
 		return nil, fmt.Errorf("Received unexpected object: %v", o)
@@ -117,8 +120,6 @@ func convertToPod(o interface{}) (*apiv1.Pod, error) {
 	if !ok {
 		return nil, fmt.Errorf("DeletedFinalStateUnknown contained non-Pod object: %v", deletedState.Obj)
 	}
-	}
-
 	return pod, nil
 }
 

discovery/kubernetes/service.go

@@ -98,8 +98,10 @@ func (s *Service) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
 }
 
 func convertToService(o interface{}) (*apiv1.Service, error) {
-	service, isService := o.(*apiv1.Service)
-	if !isService {
+	service, ok := o.(*apiv1.Service)
+	if ok {
+		return service, nil
+	}
 	deletedState, ok := o.(cache.DeletedFinalStateUnknown)
 	if !ok {
 		return nil, fmt.Errorf("Received unexpected object: %v", o)
@@ -108,8 +110,6 @@ func convertToService(o interface{}) (*apiv1.Service, error) {
 	if !ok {
 		return nil, fmt.Errorf("DeletedFinalStateUnknown contained non-Service object: %v", deletedState.Obj)
 	}
-	}
-
 	return service, nil
 }
 
@@ -129,6 +129,7 @@ func serviceLabels(svc *apiv1.Service) model.LabelSet {
 	ls := make(model.LabelSet, len(svc.Labels)+len(svc.Annotations)+2)
 
 	ls[serviceNameLabel] = lv(svc.Name)
+	ls[namespaceLabel] = lv(svc.Namespace)
 
 	for k, v := range svc.Labels {
 		ln := strutil.SanitizeLabelName(serviceLabelPrefix + k)
@@ -147,7 +148,6 @@ func (s *Service) buildService(svc *apiv1.Service) *config.TargetGroup {
 		Source: serviceSource(svc),
 	}
 	tg.Labels = serviceLabels(svc)
-	tg.Labels[namespaceLabel] = lv(svc.Namespace)
 
 	for _, port := range svc.Spec.Ports {
 		addr := net.JoinHostPort(svc.Name+"."+svc.Namespace+".svc", strconv.FormatInt(int64(port.Port), 10))

documentation/examples/prometheus-kubernetes.yml

@@ -192,7 +192,7 @@ scrape_configs:
   - source_labels: [__address__]
     target_label: __param_target
   - target_label: __address__
-    replacement: blackbox
+    replacement: blackbox-exporter.example.com:9115
   - source_labels: [__param_target]
     target_label: instance
   - action: labelmap
@@ -202,6 +202,40 @@ scrape_configs:
   - source_labels: [__meta_kubernetes_service_name]
     target_label: kubernetes_name
 
+# Example scrape config for probing ingresses via the Blackbox Exporter.
+#
+# The relabeling allows the actual ingress scrape endpoint to be configured
+# via the following annotations:
+#
+# * `prometheus.io/probe`: Only probe services that have a value of `true`
+- job_name: 'kubernetes-ingresses'
+
+  metrics_path: /probe
+  params:
+    module: [http_2xx]
+
+  kubernetes_sd_configs:
+    - role: ingress
+
+  relabel_configs:
+    - source_labels: [__meta_kubernetes_ingress_annotation_prometheus_io_probe]
+      action: keep
+      regex: true
+    - source_labels: [__meta_kubernetes_ingress_scheme,__address__,__meta_kubernetes_ingress_path]
+      regex: (.+);(.+);(.+)
+      replacement: ${1}://${2}${3}
+      target_label: __param_target
+    - target_label: __address__
+      replacement: blackbox-exporter.example.com:9115
+    - source_labels: [__param_target]
+      target_label: instance
+    - action: labelmap
+      regex: __meta_kubernetes_ingress_label_(.+)
+    - source_labels: [__meta_kubernetes_namespace]
+      target_label: kubernetes_namespace
+    - source_labels: [__meta_kubernetes_ingress_name]
+      target_label: kubernetes_name
+
 # Example scrape config for pods
 #
 # The relabeling allows the actual pod scrape endpoint to be configured via the