Report AvailableComponents via OpAMP supervisor

.chloggen/report-available-components-opamp-supervisor.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: opampsupervisor
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Support retrieval of available components via the OpAMP supervisor.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [37247]
+
+# (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: []

cmd/opampsupervisor/README.md

@@ -77,6 +77,7 @@ For a list of open issues related to the Supervisor, see [these issues](https://
 | AcceptsRestartCommand          | <https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/21077> |
 | ReportsHealth                  | ⚠️                                                                               |
 | ReportsRemoteConfig            | <https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/21079> |
+| ReportsAvailableComponents     | <https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/37247> |
 
 ### Supervisor specification features
 

cmd/opampsupervisor/go.mod

@@ -2,6 +2,8 @@ module github.com/open-telemetry/opentelemetry-collector-contrib/cmd/opampsuperv
 
 go 1.22.0
 
+replace github.com/open-telemetry/opamp-go => /Users/ian/git/opamp-go
+
 require (
 	github.com/cenkalti/backoff/v4 v4.3.0
 	github.com/google/uuid v1.6.0
@@ -10,7 +12,7 @@ require (
 	github.com/knadh/koanf/providers/file v1.1.2
 	github.com/knadh/koanf/providers/rawbytes v0.1.0
 	github.com/knadh/koanf/v2 v2.1.2
-	github.com/open-telemetry/opamp-go v0.18.0
+	github.com/open-telemetry/opamp-go v0.18.1-0.20250109233938-e6fac32dddf5
 	github.com/stretchr/testify v1.10.0
 	go.opentelemetry.io/collector/config/configopaque v1.23.1-0.20250114172347-71aae791d7f8
 	go.opentelemetry.io/collector/config/configtls v1.23.1-0.20250114172347-71aae791d7f8

cmd/opampsupervisor/supervisor/config/config.go

@@ -95,6 +95,7 @@ type Capabilities struct {
 	ReportsOwnMetrics              bool `mapstructure:"reports_own_metrics"`
 	ReportsHealth                  bool `mapstructure:"reports_health"`
 	ReportsRemoteConfig            bool `mapstructure:"reports_remote_config"`
+	ReportsAvailableComponents     bool `mapstructure:"reports_available_components"`
 }
 
 func (c Capabilities) SupportedCapabilities() protobufs.AgentCapabilities {
@@ -128,6 +129,10 @@ func (c Capabilities) SupportedCapabilities() protobufs.AgentCapabilities {
 		supportedCapabilities |= protobufs.AgentCapabilities_AgentCapabilities_AcceptsOpAMPConnectionSettings
 	}
 
+	if c.ReportsAvailableComponents {
+		supportedCapabilities |= protobufs.AgentCapabilities_AgentCapabilities_ReportsAvailableComponents
+	}
+
 	return supportedCapabilities
 }
 

cmd/opampsupervisor/supervisor/config/config_test.go

@@ -481,6 +481,7 @@ func TestCapabilities_SupportedCapabilities(t *testing.T) {
 				ReportsOwnMetrics:              true,
 				ReportsHealth:                  true,
 				ReportsRemoteConfig:            true,
+				ReportsAvailableComponents:     true,
 			},
 			expectedAgentCapabilities: protobufs.AgentCapabilities_AgentCapabilities_ReportsStatus |
 				protobufs.AgentCapabilities_AgentCapabilities_ReportsEffectiveConfig |
@@ -489,7 +490,8 @@ func TestCapabilities_SupportedCapabilities(t *testing.T) {
 				protobufs.AgentCapabilities_AgentCapabilities_AcceptsRemoteConfig |
 				protobufs.AgentCapabilities_AgentCapabilities_ReportsRemoteConfig |
 				protobufs.AgentCapabilities_AgentCapabilities_AcceptsRestartCommand |
-				protobufs.AgentCapabilities_AgentCapabilities_AcceptsOpAMPConnectionSettings,
+				protobufs.AgentCapabilities_AgentCapabilities_AcceptsOpAMPConnectionSettings |
+				protobufs.AgentCapabilities_AgentCapabilities_ReportsAvailableComponents,
 		},
 	}
 

cmd/opampsupervisor/supervisor/server.go

@@ -13,7 +13,7 @@ import (
 )
 
 type flattenedSettings struct {
-	onMessage         func(conn serverTypes.Connection, message *protobufs.AgentToServer)
+	onMessage         func(conn serverTypes.Connection, message *protobufs.AgentToServer) *protobufs.ServerToAgent
 	onConnecting      func(request *http.Request) (shouldConnect bool, rejectStatusCode int)
 	onConnectionClose func(conn serverTypes.Connection)
 	endpoint          string
@@ -53,7 +53,7 @@ func (fs flattenedSettings) OnConnected(_ context.Context, _ serverTypes.Connect
 
 func (fs flattenedSettings) OnMessage(_ context.Context, conn serverTypes.Connection, message *protobufs.AgentToServer) *protobufs.ServerToAgent {
 	if fs.onMessage != nil {
-		fs.onMessage(conn, message)
+		return fs.onMessage(conn, message)
 	}
 
 	return &protobufs.ServerToAgent{}

cmd/opampsupervisor/supervisor/server_test.go

@@ -60,8 +60,9 @@ func Test_flattenedSettings_OnConnecting(t *testing.T) {
 func Test_flattenedSettings_OnMessage(t *testing.T) {
 	onMessageFuncCalled := false
 	fs := flattenedSettings{
-		onMessage: func(_ serverTypes.Connection, _ *protobufs.AgentToServer) {
+		onMessage: func(_ serverTypes.Connection, _ *protobufs.AgentToServer) *protobufs.ServerToAgent {
 			onMessageFuncCalled = true
+			return &protobufs.ServerToAgent{}
 		},
 	}
 

cmd/opampsupervisor/supervisor/supervisor.go

@@ -103,7 +103,8 @@ type Supervisor struct {
 	// Supervisor's own config.
 	config config.Supervisor
 
-	agentDescription *atomic.Value
+	agentDescription    *atomic.Value
+	availableComponents *atomic.Value
 
 	// Supervisor's persistent state
 	persistentState *persistentState
@@ -174,6 +175,7 @@ func NewSupervisor(logger *zap.Logger, cfg config.Supervisor) (*Supervisor, erro
 		cfgState:                     &atomic.Value{},
 		effectiveConfig:              &atomic.Value{},
 		agentDescription:             &atomic.Value{},
+		availableComponents:          &atomic.Value{},
 		doneChan:                     make(chan struct{}),
 		customMessageToServer:        make(chan *protobufs.CustomMessage, maxBufferedCustomMessages),
 		agentConn:                    &atomic.Value{},
@@ -302,14 +304,19 @@ func (s *Supervisor) getBootstrapInfo() (err error) {
 	var connected atomic.Bool
 
 	// Start a one-shot server to get the Collector's agent description
-	// using the Collector's OpAMP extension.
+	// and available components using the Collector's OpAMP extension.
 	err = srv.Start(flattenedSettings{
 		endpoint: fmt.Sprintf("localhost:%d", s.opampServerPort),
 		onConnecting: func(_ *http.Request) (bool, int) {
 			connected.Store(true)
 			return true, http.StatusOK
 		},
-		onMessage: func(_ serverTypes.Connection, message *protobufs.AgentToServer) {
+		onMessage: func(_ serverTypes.Connection, message *protobufs.AgentToServer) *protobufs.ServerToAgent {
+			response := &protobufs.ServerToAgent{}
+			if message.GetAvailableComponents() != nil {
+				s.setAvailableComponents(message.AvailableComponents)
+			}
+
 			if message.AgentDescription != nil {
 				instanceIDSeen := false
 				s.setAgentDescription(message.AgentDescription)
@@ -324,19 +331,39 @@ func (s *Supervisor) getBootstrapInfo() (err error) {
 								"the Collector's instance ID (%s) does not match with the instance ID set by the Supervisor (%s)",
 								attr.Value.GetStringValue(),
 								s.persistentState.InstanceID.String())
-							return
+							return response
 						}
 						instanceIDSeen = true
 					}
 				}
 
 				if !instanceIDSeen {
 					done <- errors.New("the Collector did not specify an instance ID in its AgentDescription message")
-					return
+					return response
 				}
+			}
 
-				done <- nil
+			// agent description must be defined
+			_, ok := s.agentDescription.Load().(*protobufs.AgentDescription)
+			if !ok {
+				return response
+			}
+
+			availableComponents, availableComponentsOk := s.availableComponents.Load().(*protobufs.AvailableComponents)
+			if availableComponentsOk {
+				// must have a full list of components if available components have been reported
+				if availableComponents.GetComponents() != nil {
+					done <- nil
+				} else {
+					// if we don't have a full component list, ask for it
+					response.Flags = uint64(protobufs.ServerToAgentFlags_ServerToAgentFlags_ReportAvailableComponents)
+				}
+				return response
 			}
+
+			// if available components have not been reported, agent description is sufficient
+			done <- nil
+			return response
 		},
 	}.toServerSettings())
 	if err != nil {
@@ -456,6 +483,10 @@ func (s *Supervisor) startOpAMPClient() error {
 		return err
 	}
 
+	if ac, ok := s.availableComponents.Load().(*protobufs.AvailableComponents); ok {
+		settings.AvailableComponents = ac
+	}
+
 	s.logger.Debug("Starting OpAMP client...")
 	if err = s.opampClient.Start(context.Background(), settings); err != nil {
 		return err
@@ -505,7 +536,7 @@ func (s *Supervisor) startOpAMPServer() error {
 	return nil
 }
 
-func (s *Supervisor) handleAgentOpAMPMessage(conn serverTypes.Connection, message *protobufs.AgentToServer) {
+func (s *Supervisor) handleAgentOpAMPMessage(conn serverTypes.Connection, message *protobufs.AgentToServer) *protobufs.ServerToAgent {
 	s.agentConn.Store(conn)
 
 	s.logger.Debug("Received OpAMP message from the agent")
@@ -551,6 +582,8 @@ func (s *Supervisor) handleAgentOpAMPMessage(conn serverTypes.Connection, messag
 		s.logger.Debug("Received health status from agent", zap.Bool("healthy", message.Health.Healthy))
 		s.lastHealthFromClient = message.Health
 	}
+
+	return &protobufs.ServerToAgent{}
 }
 
 func (s *Supervisor) forwardCustomMessagesToServerLoop() {
@@ -584,6 +617,11 @@ func (s *Supervisor) setAgentDescription(ad *protobufs.AgentDescription) {
 	s.agentDescription.Store(ad)
 }
 
+// setAvailableComponents sets the available components of the OpAMP agent
+func (s *Supervisor) setAvailableComponents(ac *protobufs.AvailableComponents) {
+	s.availableComponents.Store(ac)
+}
+
 // applyKeyValueOverrides merges the overrides map into the array of key value pairs.
 // If a key from overrides already exists in the array of key value pairs, it is overwritten by the value from the overrides map.
 // An array of KeyValue pair is returned, with each key value pair having a distinct key.
@@ -1022,7 +1060,7 @@ func (s *Supervisor) startAgent() (agentStartStatus, error) {
 	err := s.commander.Start(context.Background())
 	if err != nil {
 		s.logger.Error("Cannot start the agent", zap.Error(err))
-		startErr := fmt.Errorf("Cannot start the agent: %w", err)
+		startErr := fmt.Errorf("cannot start the agent: %w", err)
 		err = s.opampClient.SetHealth(&protobufs.ComponentHealth{Healthy: false, LastError: startErr.Error()})
 		if err != nil {
 			s.logger.Error("Failed to report OpAMP client health", zap.Error(err))