Set agent.name to hostname by default

Since ECS does not define agent.hostname it will be removed in a future release.
In order to always have a field available to identify the agent by name we will
set the agent.name to hostname unless the user has provided a custom name.

Relates elastic#16377

CHANGELOG.next.asciidoc

@@ -210,6 +210,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Add keystore support for autodiscover static configurations. {pull]16306[16306]
 - Add Kerberos support to Elasticsearch output. {pull}17927[17927]
 - Add support for fixed length extraction in `dissect` processor. {pull}17191[17191]
+- Set `agent.name` to the hostname by default. {issue}16377[16377] {pull}18000[18000]
 
 *Auditbeat*
 

heartbeat/cmd/root.go

@@ -41,7 +41,7 @@ var RootCmd *cmd.BeatsRootCmd
 func init() {
 	settings := instance.Settings{
 		Name:          Name,
-		Processing:    processing.MakeDefaultSupport(true, processing.WithECS, processing.WithBeatMeta("agent")),
+		Processing:    processing.MakeDefaultSupport(true, processing.WithECS, processing.WithAgentMeta()),
 		HasDashboards: false,
 	}
 	RootCmd = cmd.GenRootCmdWithSettings(beater.New, settings)

libbeat/publisher/processing/default.go

@@ -76,14 +76,14 @@ type builtinModifier func(beat.Info) common.MapStr
 // MakeDefaultBeatSupport automatically adds the `ecs.version`, `host.name` and `agent.X` fields
 // to each event.
 func MakeDefaultBeatSupport(normalize bool) SupportFactory {
-	return MakeDefaultSupport(normalize, WithECS, WithHost, WithBeatMeta("agent"))
+	return MakeDefaultSupport(normalize, WithECS, WithHost, WithAgentMeta())
 }
 
 // MakeDefaultObserverSupport creates a new SupportFactory based on NewDefaultSupport.
 // MakeDefaultObserverSupport automatically adds the `ecs.version` and `observer.X` fields
 // to each event.
 func MakeDefaultObserverSupport(normalize bool) SupportFactory {
-	return MakeDefaultSupport(normalize, WithECS, WithBeatMeta("observer"))
+	return MakeDefaultSupport(normalize, WithECS, WithObserverMeta())
 }
 
 // MakeDefaultSupport creates a new SupportFactory for use with the publisher pipeline.
@@ -139,21 +139,42 @@ var WithHost modifier = builtinModifier(func(info beat.Info) common.MapStr {
 	}
 })
 
-// WithBeatMeta adds beat meta information as builtin fields to a processing pipeline.
-// The `key` parameter defines the field to be used.
-func WithBeatMeta(key string) modifier {
+// WithAgentMeta adds agent meta information as builtin fields to a processing
+// pipeline.
+func WithAgentMeta() modifier {
 	return builtinModifier(func(info beat.Info) common.MapStr {
 		metadata := common.MapStr{
-			"type":         info.Beat,
 			"ephemeral_id": info.EphemeralID.String(),
-			"hostname":     info.Hostname,
 			"id":           info.ID.String(),
+			"name":         info.Hostname,
+			"type":         info.Beat,
+			"version":      info.Version,
+			// hostname is deprecated. To be removed for 8.0. It's not in ECS.
+			// See https://github.com/elastic/beats/issues/16377.
+			"hostname": info.Hostname,
+		}
+		if info.Name != "" {
+			metadata["name"] = info.Name
+		}
+		return common.MapStr{"agent": metadata}
+	})
+}
+
+// WithObserverMeta adds beat meta information as builtin fields to a processing
+// pipeline.
+func WithObserverMeta() modifier {
+	return builtinModifier(func(info beat.Info) common.MapStr {
+		metadata := common.MapStr{
+			"type":         info.Beat,                 // Per ECS this is not a valid type value.
+			"ephemeral_id": info.EphemeralID.String(), // Not in ECS.
+			"hostname":     info.Hostname,
+			"id":           info.ID.String(), // Not in ECS.
 			"version":      info.Version,
 		}
 		if info.Name != info.Hostname {
 			metadata.Put("name", info.Name)
 		}
-		return common.MapStr{key: metadata}
+		return common.MapStr{"observer": metadata}
 	})
 }
 

libbeat/publisher/processing/default_test.go

@@ -184,6 +184,7 @@ func TestProcessorsConfigs(t *testing.T) {
 				"agent": common.MapStr{
 					"ephemeral_id": "123e4567-e89b-12d3-a456-426655440000",
 					"hostname":     "test.host.name",
+					"name":         "test.host.name",
 					"id":           "123e4567-e89b-12d3-a456-426655440001",
 					"type":         "test",
 					"version":      "0.1",