[Hints Support] Add default host

changelog/fragments/1696935756-add-default-host.yaml

@@ -0,0 +1,32 @@
+# Kind can be one of:
+# - breaking-change: a change to previously-documented behavior
+# - deprecation: functionality that is being removed in a later release
+# - bug-fix: fixes a problem in a previous version
+# - enhancement: extends functionality but does not break or fix existing behavior
+# - feature: new functionality
+# - known-issue: problems that we are aware of in a given version
+# - security: impacts on the security of a product or a user’s deployment.
+# - upgrade: important information for someone upgrading from a prior version
+# - other: does not fit into any of the other categories
+kind: feature
+
+# Change summary; a 80ish characters long description of the change.
+summary: Hints Autodiscovery for Elastic Agent - Add default host for each container in a pod
+
+# Long description; in case the summary is not enough to describe the change
+# this field accommodate a description without length limits.
+# NOTE: This field will be rendered only for breaking-change and known-issue kinds at the moment.
+#description:
+
+# Affected component; usually one of "elastic-agent", "fleet-server", "filebeat", "metricbeat", "auditbeat", "all", etc.
+component: elastic-agent
+
+# PR URL; optional; the PR number that added the changeset.
+# If not present is automatically filled by the tooling finding the PR where this changelog fragment has been added.
+# NOTE: the tooling supports backports, so it's able to fill the original PR number instead of the backport PR number.
+# Please provide it if you are adding a fragment for a different PR.
+pr: https://github.com/elastic/elastic-agent/pull/3575
+
+# Issue URL; optional; the GitHub issue related to this changeset (either closes or is part of).
+# If not present is automatically filled by the tooling with the issue linked to the PR number.
+issue: https://github.com/elastic/elastic-agent/issues/1453

internal/pkg/composable/providers/kubernetes/hints.go

@@ -26,6 +26,9 @@ const (
 	username    = "username"
 	password    = "password"
 	stream      = "stream" // this is the container stream: stdout/stderr
+
+	hints      = "hints"
+	processors = "processors"
 )
 
 type hintsBuilder struct {
@@ -250,83 +253,66 @@ func GenerateHintsMapping(hints mapstr.M, kubeMeta mapstr.M, logger *logp.Logger
 	return hintsMapping
 }
 
-// Generates the hints and processor mappings from provided pod annotation map
+// GetHintsMapping Generates the hints and processor mappings from provided pod annotation map
 func GetHintsMapping(k8sMapping map[string]interface{}, logger *logp.Logger, prefix string, cID string) hintsData {
 	hintData := hintsData{
 		composableMapping: mapstr.M{},
 		processors:        []mapstr.M{},
 	}
-	var hints mapstr.M
-	var containerProcessors []mapstr.M
-
-	if ann, ok := k8sMapping["annotations"]; ok {
-		annotations, _ := ann.(mapstr.M)
-
-		if containerEntries, err := annotations.GetValue(prefix + ".hints"); err == nil {
-			entries, ok := containerEntries.(mapstr.M)
-			if ok && len(entries) > 0 {
-				for key := range entries {
-					parts := strings.Split(key, "/")
-
-					if len(parts) > 1 {
-						if con, ok := k8sMapping["container"]; ok {
-							containers, ok := con.(mapstr.M)
-							if ok {
-								if cname, err := containers.GetValue("name"); err == nil {
-									if parts[0] == cname {
-										// If there are hints like co.elastic.hints.<container_name>/ then add the values after the / to the corresponding container
-										// Eg Annotation "co.elastic.hints.nginx/stream: stderr" will create a hints entry for container nginx
-										hints, containerProcessors = GenerateHintsForContainer(annotations, parts[0], prefix)
-									}
-								}
-							}
-						}
-					}
-				}
-			}
-		} else {
-			// If there are top level hints like co.elastic.hints/ then just add the values after the /
-			// Eg. Annotation "co.elastic.hints/stream: stderr" will will create a hints entries for all containers in the pod
-			hints = utils.GenerateHints(annotations, "", prefix)
+	cName := ""
+	cHost := ""
+
+	ann, ok := k8sMapping["annotations"]
+	if !ok {
+		return hintData
+	}
+	annotations, _ := ann.(mapstr.M)
+
+	// Get the name of the container from the metadata. We need it to extract the hints that affect it directly.
+	// E.g. co.elastic.hints.<container-name>/host: "..."
+	if con, ok := k8sMapping["container"]; ok {
+		containers, _ := con.(mapstr.M)
+		if name, err := containers.GetValue("name"); err == nil {
+			cName = name.(string)
+		}
+		if cPort, err := containers.GetValue("port"); err == nil {
+			// This is the default for the host value of a specific container.
+			cHost = "${kubernetes.pod.ip}:" + cPort.(string)
 		}
-		logger.Debugf("Extracted hints are :%v", hints)
+	}
 
-		if len(hints) > 0 {
-			hintData = GenerateHintsResult(hints, k8sMapping, annotations, logger, prefix, cID)
+	hintsExtracted := utils.GenerateHints(annotations, cName, prefix)
+	if len(hintsExtracted) == 0 {
+		return hintData
+	}
 
-			// Only if there are processors defined in a specific container we append them to the processors of the top level
-			if len(containerProcessors) > 0 {
-				hintData.processors = append(hintData.processors, containerProcessors...)
+	// Check if host exists. Otherwise, add default entry for it.
+	if cHost != "" {
+		if hintsValues, ok := hintsExtracted[hints].(mapstr.M); ok {
+			if _, ok := hintsValues[host]; !ok {
+				hintsValues[host] = cHost
+			}
+		} else {
+			hintsExtracted[hints] = mapstr.M{
+				host: cHost,
 			}
-			logger.Debugf("Generated Processors mapping :%v", hintData.processors)
 		}
 	}
 
-	return hintData
-}
-
-// Generates hints and processors list for specific containers
-func GenerateHintsForContainer(annotations mapstr.M, parts, prefix string) (mapstr.M, []mapstr.M) {
-	hints := utils.GenerateHints(annotations, parts, prefix)
-	// Processors for specific container
-	// We need to make an extra check if we have processors added only to the specific containers
-	containerProcessors := utils.GetConfigs(annotations, prefix, "hints."+parts+"/processors")
-
-	return hints, containerProcessors
-}
+	logger.Debugf("Extracted hints are :%v", hintsExtracted)
 
-// Generates the final hintData (hints and processors) struct that will be emitted in pods.
-func GenerateHintsResult(hints mapstr.M, k8sMapping map[string]interface{}, annotations mapstr.M, logger *logp.Logger, prefix, cID string) hintsData {
-	hintData := hintsData{
-		composableMapping: mapstr.M{},
-		processors:        []mapstr.M{},
-	}
-
-	hintData.composableMapping = GenerateHintsMapping(hints, k8sMapping, logger, cID)
+	hintData.composableMapping = GenerateHintsMapping(hintsExtracted, k8sMapping, logger, cID)
 	logger.Debugf("Generated hints mappings :%v", hintData.composableMapping)
 
-	// Eg  co.elastic.hints/processors.decode_json_fields.fields: "message" will add a processor in all containers of pod
-	hintData.processors = utils.GetConfigs(annotations, prefix, processorhints)
+	hintData.processors = utils.GetConfigs(annotations, prefix, hints+"/"+processors)
+	// We need to check the processors for the specific container, if they exist.
+	if cName != "" {
+		containerProcessors := utils.GetConfigs(annotations, prefix, hints+"."+cName+"/"+processors)
+		if len(containerProcessors) > 0 {
+			hintData.processors = append(hintData.processors, containerProcessors...)
+		}
+	}
+	logger.Debugf("Generated Processors mapping :%v", hintData.processors)
 
 	return hintData
 }

internal/pkg/composable/providers/kubernetes/hints_test.go

@@ -591,3 +591,134 @@ func TestGenerateHintsMappingWithProcessorsForContainer(t *testing.T) {
 		assert.Contains(t, expectedprocesors, hintData.processors[1])
 	}
 }
+
+func TestDefaultHost(t *testing.T) {
+	logger := getLogger()
+	cID := "abcd"
+
+	mapping := map[string]interface{}{
+		"namespace": "testns",
+		"pod": mapstr.M{
+			"uid":  string(types.UID(uid)),
+			"name": "testpod",
+			"ip":   "127.0.0.5",
+		},
+		"annotations": mapstr.M{
+			"app": "production",
+			"co": mapstr.M{
+				"elastic": mapstr.M{
+					"hints/package": "redis",
+					"hints": mapstr.M{
+						"redis-1/host":   "${kubernetes.pod.ip}:6379",
+						"redis-1/stream": "stderr",
+						"redis-2/host":   "${kubernetes.pod.ip}:6400",
+						"redis-4/stream": "stderr",
+					},
+				},
+			},
+		},
+	}
+
+	addContainerMapping := func(mapping map[string]interface{}, container mapstr.M) map[string]interface{} {
+		clone := make(map[string]interface{}, len(mapping))
+		for k, v := range mapping {
+			clone[k] = v
+		}
+		clone["container"] = container
+		return clone
+	}
+
+	tests := []struct {
+		msg      string
+		mapping  map[string]interface{}
+		expected mapstr.M
+	}{
+		{
+			msg: "Test container with two hints (redis-1), of which one is host.",
+			mapping: addContainerMapping(mapping,
+				mapstr.M{
+					"name": "redis-1",
+					"port": "6379",
+					"id":   cID,
+				},
+			),
+			expected: mapstr.M{
+				"container_id": cID,
+				"redis": mapstr.M{
+					"container_logs": mapstr.M{
+						"enabled": true,
+					},
+					"enabled": true,
+					"host":    "127.0.0.5:6379",
+					"stream":  "stderr",
+				},
+			},
+		},
+		{
+			msg: "Test container with only one hint for host (redis-2).",
+			mapping: addContainerMapping(mapping,
+				mapstr.M{
+					"name": "redis-2",
+					"port": "6400",
+					"id":   cID,
+				},
+			),
+			expected: mapstr.M{
+				"container_id": cID,
+				"redis": mapstr.M{
+					"container_logs": mapstr.M{
+						"enabled": true,
+					},
+					"enabled": true,
+					"host":    "127.0.0.5:6400",
+				},
+			},
+		},
+		{
+			msg: "Test container without hints and check for the default host (redis-3).",
+			mapping: addContainerMapping(mapping,
+				mapstr.M{
+					"name": "redis-3",
+					"port": "7000",
+					"id":   cID,
+				},
+			),
+			expected: mapstr.M{
+				"container_id": cID,
+				"redis": mapstr.M{
+					"container_logs": mapstr.M{
+						"enabled": true,
+					},
+					"enabled": true,
+					"host":    "127.0.0.5:7000",
+				},
+			},
+		},
+		{
+			msg: "Test container with one hint for stream and without port defined (redis-4).",
+			mapping: addContainerMapping(mapping,
+				mapstr.M{
+					"name": "redis-4",
+					"id":   cID,
+				},
+			),
+			expected: mapstr.M{
+				"container_id": cID,
+				"redis": mapstr.M{
+					"container_logs": mapstr.M{
+						"enabled": true,
+					},
+					"enabled": true,
+					"stream":  "stderr",
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.msg, func(t *testing.T) {
+			hintData := GetHintsMapping(test.mapping, logger, "co.elastic", cID)
+			assert.Equal(t, test.expected, hintData.composableMapping)
+		})
+	}
+}

internal/pkg/composable/providers/kubernetes/pod.go

@@ -24,10 +24,6 @@ import (
 	"github.com/elastic/elastic-agent/internal/pkg/composable"
 )
 
-const (
-	processorhints = "hints/processors"
-)
-
 type pod struct {
 	watcher           kubernetes.Watcher
 	nodeWatcher       kubernetes.Watcher