Fix metrics hints builder to avoid wrong container metadata usage whe…

…n port is not exposed (#18979)

CHANGELOG.next.asciidoc

@@ -133,6 +133,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - The `monitoring.elasticsearch.api_key` value is correctly base64-encoded before being sent to the monitoring Elasticsearch cluster. {issue}18939[18939] {pull}18945[18945]
 - Fix kafka topic setting not allowing upper case characters. {pull}18854[18854] {issue}18640[18640]
 - Fix redis key setting not allowing upper case characters. {pull}18854[18854] {issue}18640[18640]
+- Fix metrics hints builder to avoid wrong container metadata usage when port is not exposed {pull}18979[18979]
 
 *Auditbeat*
 

libbeat/autodiscover/providers/kubernetes/pod.go

@@ -275,6 +275,26 @@ func (p *pod) emitEvents(pod *kubernetes.Pod, flag string, containers []kubernet
 		}
 	}
 
+	// Pass annotations to all events so that it can be used in templating and by annotation builders.
+	var (
+		annotations = common.MapStr{}
+		nsAnn       = common.MapStr{}
+	)
+	for k, v := range pod.GetObjectMeta().GetAnnotations() {
+		safemapstr.Put(annotations, k, v)
+	}
+
+	if p.namespaceWatcher != nil {
+		if rawNs, ok, err := p.namespaceWatcher.Store().GetByKey(pod.Namespace); ok && err == nil {
+			if namespace, ok := rawNs.(*kubernetes.Namespace); ok {
+				for k, v := range namespace.GetAnnotations() {
+					safemapstr.Put(nsAnn, k, v)
+				}
+			}
+		}
+	}
+
+	emitted := 0
 	// Emit container and port information
 	for _, c := range containers {
 		// If it doesn't have an ID, container doesn't exist in
@@ -301,39 +321,27 @@ func (p *pod) emitEvents(pod *kubernetes.Pod, flag string, containers []kubernet
 		// Information that can be used in discovering a workload
 		kubemeta := meta.Clone()
 		kubemeta["container"] = cmeta
-
-		// Pass annotations to all events so that it can be used in templating and by annotation builders.
-		annotations := common.MapStr{}
-		for k, v := range pod.GetObjectMeta().GetAnnotations() {
-			safemapstr.Put(annotations, k, v)
-		}
 		kubemeta["annotations"] = annotations
-		if p.namespaceWatcher != nil {
-			if rawNs, ok, err := p.namespaceWatcher.Store().GetByKey(pod.Namespace); ok && err == nil {
-				if namespace, ok := rawNs.(*kubernetes.Namespace); ok {
-					nsAnn := common.MapStr{}
-
-					for k, v := range namespace.GetAnnotations() {
-						safemapstr.Put(nsAnn, k, v)
-					}
-					kubemeta["namespace_annotations"] = nsAnn
-				}
-			}
+		if len(nsAnn) != 0 {
+			kubemeta["namespace_annotations"] = nsAnn
 		}
 
 		// Without this check there would be overlapping configurations with and without ports.
 		if len(c.Ports) == 0 {
+			// Set a zero port on the event to signify that the event is from a container
 			event := bus.Event{
 				"provider":   p.uuid,
 				"id":         eventID,
 				flag:         true,
 				"host":       host,
+				"port":       0,
 				"kubernetes": kubemeta,
 				"meta": common.MapStr{
 					"kubernetes": meta,
 				},
 			}
 			p.publish(event)
+			emitted++
 		}
 
 		for _, port := range c.Ports {
@@ -349,6 +357,36 @@ func (p *pod) emitEvents(pod *kubernetes.Pod, flag string, containers []kubernet
 				},
 			}
 			p.publish(event)
+			emitted++
 		}
 	}
+
+	// Finally publish a pod level event so that hints that have no exposed ports can get processed.
+	// Log hints would just ignore this event as there is no ${data.container.id}
+	// Publish the pod level hint only if atleast one container level hint was emitted. This ensures that there is
+	// no unnecessary pod level events emitted prematurely.
+	if emitted != 0 {
+		meta := p.metagen.Generate(pod)
+
+		// Information that can be used in discovering a workload
+		kubemeta := meta.Clone()
+		kubemeta["annotations"] = annotations
+		if len(nsAnn) != 0 {
+			kubemeta["namespace_annotations"] = nsAnn
+		}
+
+		// Don't set a port on the event
+		event := bus.Event{
+			"provider":   p.uuid,
+			"id":         fmt.Sprint(pod.GetObjectMeta().GetUID()),
+			flag:         true,
+			"host":       host,
+			"kubernetes": kubemeta,
+			"meta": common.MapStr{
+				"kubernetes": meta,
+			},
+		}
+		p.publish(event)
+
+	}
 }

libbeat/autodiscover/providers/kubernetes/pod_test.go

@@ -392,6 +392,7 @@ func TestEmitEvent(t *testing.T) {
 			Expected: bus.Event{
 				"start":    true,
 				"host":     "127.0.0.1",
+				"port":     0,
 				"id":       cid,
 				"provider": UUID,
 				"kubernetes": common.MapStr{
@@ -525,6 +526,7 @@ func TestEmitEvent(t *testing.T) {
 				"stop":     true,
 				"host":     "",
 				"id":       cid,
+				"port":     0,
 				"provider": UUID,
 				"kubernetes": common.MapStr{
 					"container": common.MapStr{
@@ -593,6 +595,7 @@ func TestEmitEvent(t *testing.T) {
 			Expected: bus.Event{
 				"stop":     true,
 				"host":     "127.0.0.1",
+				"port":     0,
 				"id":       cid,
 				"provider": UUID,
 				"kubernetes": common.MapStr{

metricbeat/autodiscover/builder/hints/metrics.go

@@ -56,6 +56,8 @@ const (
 type metricHints struct {
 	Key      string
 	Registry *mb.Register
+
+	logger *logp.Logger
 }
 
 // NewMetricHints builds a new metrics builder based on hints
@@ -67,18 +69,24 @@ func NewMetricHints(cfg *common.Config) (autodiscover.Builder, error) {
 		return nil, fmt.Errorf("unable to unpack hints config due to error: %v", err)
 	}
 
-	return &metricHints{config.Key, config.Registry}, nil
+	return &metricHints{config.Key, config.Registry, logp.NewLogger("hints.builder")}, nil
 }
 
 // Create configs based on hints passed from providers
 func (m *metricHints) CreateConfig(event bus.Event, options ...ucfg.Option) []*common.Config {
-	var config []*common.Config
+	var (
+		config []*common.Config
+		noPort bool
+	)
 	host, _ := event["host"].(string)
 	if host == "" {
 		return config
 	}
 
-	port, _ := common.TryToInt(event["port"])
+	port, ok := common.TryToInt(event["port"])
+	if !ok {
+		noPort = true
+	}
 
 	hints, ok := event["hints"].(common.MapStr)
 	if !ok {
@@ -105,7 +113,7 @@ func (m *metricHints) CreateConfig(event bus.Event, options ...ucfg.Option) []*c
 		return config
 	}
 
-	hosts, ok := m.getHostsWithPort(hints, port)
+	hosts, ok := m.getHostsWithPort(hints, port, noPort)
 	if !ok {
 		return config
 	}
@@ -144,14 +152,14 @@ func (m *metricHints) CreateConfig(event bus.Event, options ...ucfg.Option) []*c
 		moduleConfig["password"] = password
 	}
 
-	logp.Debug("hints.builder", "generated config: %v", moduleConfig)
+	m.logger.Debug("generated config: %v", moduleConfig)
 
 	// Create config object
 	cfg, err := common.NewConfigFrom(moduleConfig)
 	if err != nil {
-		logp.Debug("hints.builder", "config merge failed with error: %v", err)
+		logp.Debug("", "config merge failed with error: %v", err)
 	}
-	logp.Debug("hints.builder", "generated config: %+v", common.DebugString(cfg, true))
+	m.logger.Debug("generated config: %+v", common.DebugString(cfg, true))
 	config = append(config, cfg)
 
 	// Apply information in event to the template to generate the final config
@@ -181,22 +189,22 @@ func (m *metricHints) getMetricSets(hints common.MapStr, module string) []string
 	return msets
 }
 
-func (m *metricHints) getHostsWithPort(hints common.MapStr, port int) ([]string, bool) {
+func (m *metricHints) getHostsWithPort(hints common.MapStr, port int, noPort bool) ([]string, bool) {
 	var result []string
 	thosts := builder.GetHintAsList(hints, m.Key, hosts)
 
 	// Only pick hosts that have ${data.port} or the port on current event. This will make
 	// sure that incorrect meta mapping doesn't happen
 	for _, h := range thosts {
-		if strings.Contains(h, "data.port") || m.checkHostPort(h, port) ||
+		if strings.Contains(h, "data.port") && port != 0 && !noPort || m.checkHostPort(h, port) ||
 			// Use the event that has no port config if there is a ${data.host}:9090 like input
-			(port == 0 && strings.Contains(h, "data.host")) {
+			(noPort && strings.Contains(h, "data.host")) {
 			result = append(result, h)
 		}
 	}
 
 	if len(thosts) > 0 && len(result) == 0 {
-		logp.Debug("hints.builder", "no hosts selected for port %d with hints: %+v", port, thosts)
+		m.logger.Debug("no hosts selected for port %d with hints: %+v", port, thosts)
 		return nil, false
 	}
 

metricbeat/autodiscover/builder/hints/metrics_test.go

@@ -29,6 +29,7 @@ import (
 	"github.com/elastic/beats/v7/libbeat/common"
 	"github.com/elastic/beats/v7/libbeat/common/bus"
 	"github.com/elastic/beats/v7/libbeat/keystore"
+	"github.com/elastic/beats/v7/libbeat/logp"
 	"github.com/elastic/beats/v7/metricbeat/mb"
 )
 
@@ -266,6 +267,21 @@ func TestGenerateHints(t *testing.T) {
 				},
 			},
 		},
+		{
+			message: "Module with data.host defined and a zero port should not return a config",
+			event: bus.Event{
+				"host": "1.2.3.4",
+				"port": 0,
+				"hints": common.MapStr{
+					"metrics": common.MapStr{
+						"module":    "mockmoduledefaults",
+						"namespace": "test",
+						"hosts":     "${data.host}:9090",
+					},
+				},
+			},
+			len: 0,
+		},
 		{
 			message: "Module, namespace, host hint should return valid config",
 			event: bus.Event{
@@ -340,6 +356,7 @@ func TestGenerateHints(t *testing.T) {
 		m := metricHints{
 			Key:      defaultConfig().Key,
 			Registry: mockRegister,
+			logger:   logp.NewLogger("hints.builder"),
 		}
 		cfgs := m.CreateConfig(test.event)
 		assert.Equal(t, len(cfgs), test.len)
@@ -413,6 +430,7 @@ func TestGenerateHintsDoesNotAccessGlobalKeystore(t *testing.T) {
 		m := metricHints{
 			Key:      defaultConfig().Key,
 			Registry: mockRegister,
+			logger:   logp.NewLogger("hints.builder"),
 		}
 		cfgs := m.CreateConfig(test.event)
 		assert.Equal(t, len(cfgs), test.len)