[extension/opamp] Implement ReportsHealth capability (#35488)

.chloggen/opamp-extension-reportshealth.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: opampextension
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Implement `ReportsHealth` capability in OpAMP extension
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [35433]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

extension/opampextension/README.md

@@ -43,6 +43,7 @@ The following settings are optional for both transports:
   instance UID remains constant across process restarts.
 - `capabilities`: Keys with boolean true/false values that enable a particular OpAMP capability.
   - `reports_effective_config`: Whether to enable the OpAMP ReportsEffectiveConfig capability. Default is `true`.
+  - `reports_health`: Whether to enable the OpAMP ReportsHealth capability. Default is `true`.
 - `agent_description`: Setting that modifies the agent description reported to the OpAMP server.
   - `non_identifying_attributes`: A map of key value pairs that will be added to the [non-identifying attributes](https://github.com/open-telemetry/opamp-spec/blob/main/specification.md#agentdescriptionnon_identifying_attributes) reported to the OpAMP server. If an attribute collides with the default non-identifying attributes that are automatically added, the ones specified here take precedence.
 - `ppid`: An optional process ID to monitor. When this process is no longer running, the extension will emit a fatal error, causing the collector to exit. This is meant to be set by the Supervisor or some other parent process, and should not be configured manually.

extension/opampextension/config.go

@@ -54,6 +54,8 @@ type AgentDescription struct {
 type Capabilities struct {
 	// ReportsEffectiveConfig enables the OpAMP ReportsEffectiveConfig Capability. (default: true)
 	ReportsEffectiveConfig bool `mapstructure:"reports_effective_config"`
+	// ReportsHealth enables the OpAMP ReportsHealth Capability. (default: true)
+	ReportsHealth bool `mapstructure:"reports_health"`
 }
 
 func (caps Capabilities) toAgentCapabilities() protobufs.AgentCapabilities {
@@ -63,6 +65,9 @@ func (caps Capabilities) toAgentCapabilities() protobufs.AgentCapabilities {
 	if caps.ReportsEffectiveConfig {
 		agentCapabilities |= protobufs.AgentCapabilities_AgentCapabilities_ReportsEffectiveConfig
 	}
+	if caps.ReportsHealth {
+		agentCapabilities |= protobufs.AgentCapabilities_AgentCapabilities_ReportsHealth
+	}
 
 	return agentCapabilities
 }

extension/opampextension/config_test.go

@@ -8,6 +8,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/open-telemetry/opamp-go/protobufs"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"go.opentelemetry.io/collector/config/configopaque"
@@ -39,6 +40,7 @@ func TestUnmarshalConfig(t *testing.T) {
 			InstanceUID: "01BX5ZZKBKACTAV9WEVGEMMVRZ",
 			Capabilities: Capabilities{
 				ReportsEffectiveConfig: true,
+				ReportsHealth:          true,
 			},
 			PPIDPollInterval: 5 * time.Second,
 		}, cfg)
@@ -63,6 +65,7 @@ func TestUnmarshalHttpConfig(t *testing.T) {
 			InstanceUID: "01BX5ZZKBKACTAV9WEVGEMMVRZ",
 			Capabilities: Capabilities{
 				ReportsEffectiveConfig: true,
+				ReportsHealth:          true,
 			},
 			PPIDPollInterval: 5 * time.Second,
 		}, cfg)
@@ -286,3 +289,41 @@ func TestConfig_Validate(t *testing.T) {
 		})
 	}
 }
+
+func TestCapabilities_toAgentCapabilities(t *testing.T) {
+	type fields struct {
+		ReportsEffectiveConfig bool
+		ReportsHealth          bool
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		want   protobufs.AgentCapabilities
+	}{
+		{
+			name: "default capabilities",
+			fields: fields{
+				ReportsEffectiveConfig: false,
+				ReportsHealth:          false,
+			},
+			want: protobufs.AgentCapabilities_AgentCapabilities_ReportsStatus,
+		},
+		{
+			name: "all supported capabilities enabled",
+			fields: fields{
+				ReportsEffectiveConfig: true,
+				ReportsHealth:          true,
+			},
+			want: protobufs.AgentCapabilities_AgentCapabilities_ReportsStatus | protobufs.AgentCapabilities_AgentCapabilities_ReportsEffectiveConfig | protobufs.AgentCapabilities_AgentCapabilities_ReportsHealth,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			caps := Capabilities{
+				ReportsEffectiveConfig: tt.fields.ReportsEffectiveConfig,
+				ReportsHealth:          tt.fields.ReportsHealth,
+			}
+			assert.Equalf(t, tt.want, caps.toAgentCapabilities(), "toAgentCapabilities()")
+		})
+	}
+}

extension/opampextension/factory.go

@@ -27,6 +27,7 @@ func createDefaultConfig() component.Config {
 		Server: &OpAMPServer{},
 		Capabilities: Capabilities{
 			ReportsEffectiveConfig: true,
+			ReportsHealth:          true,
 		},
 		PPIDPollInterval: 5 * time.Second,
 	}

extension/opampextension/opamp_agent.go

@@ -32,6 +32,8 @@ import (
 	"github.com/open-telemetry/opentelemetry-collector-contrib/extension/opampcustommessages"
 )
 
+var _ extensioncapabilities.PipelineWatcher = (*opampAgent)(nil)
+
 type opampAgent struct {
 	cfg    *Config
 	logger *zap.Logger
@@ -121,6 +123,8 @@ func (o *opampAgent) Start(ctx context.Context, host component.Host) error {
 		return err
 	}
 
+	o.setHealth(&protobufs.ComponentHealth{Healthy: false})
+
 	o.logger.Debug("Starting OpAMP client...")
 
 	if err := o.opampClient.Start(context.Background(), settings); err != nil {
@@ -141,6 +145,7 @@ func (o *opampAgent) Shutdown(ctx context.Context) error {
 	if o.opampClient == nil {
 		return nil
 	}
+
 	o.logger.Debug("Stopping OpAMP client...")
 	err := o.opampClient.Stop(ctx)
 	// Opamp-go considers this an error, but the collector does not.
@@ -178,6 +183,16 @@ func (o *opampAgent) Register(capability string, opts ...opampcustommessages.Cus
 	return o.customCapabilityRegistry.Register(capability, opts...)
 }
 
+func (o *opampAgent) Ready() error {
+	o.setHealth(&protobufs.ComponentHealth{Healthy: true})
+	return nil
+}
+
+func (o *opampAgent) NotReady() error {
+	o.setHealth(&protobufs.ComponentHealth{Healthy: false})
+	return nil
+}
+
 func (o *opampAgent) updateEffectiveConfig(conf *confmap.Conf) {
 	o.eclk.Lock()
 	defer o.eclk.Unlock()
@@ -344,3 +359,11 @@ func (o *opampAgent) onMessage(_ context.Context, msg *types.MessageData) {
 		o.customCapabilityRegistry.ProcessMessage(msg.CustomMessage)
 	}
 }
+
+func (o *opampAgent) setHealth(ch *protobufs.ComponentHealth) {
+	if o.capabilities.ReportsHealth && o.opampClient != nil {
+		if err := o.opampClient.SetHealth(ch); err != nil {
+			o.logger.Error("Could not report health to OpAMP server", zap.Error(err))
+		}
+	}
+}

extension/opampextension/opamp_agent_test.go

@@ -31,6 +31,7 @@ func TestNewOpampAgent(t *testing.T) {
 	assert.Equal(t, "test version", o.agentVersion)
 	assert.NotEmpty(t, o.instanceID.String())
 	assert.True(t, o.capabilities.ReportsEffectiveConfig)
+	assert.True(t, o.capabilities.ReportsHealth)
 	assert.Empty(t, o.effectiveConfig)
 	assert.Nil(t, o.agentDescription)
 }