Send AgentInfo on component startup (#93)

Now, AgentInfo can be sent during component startup along with the connection information. 
The components no longer report the version on CheckinObservedVersionInfo.
The V2 client constructors either take an AgentInfo, or it is read from the StartUpInfo.

dev-tools/v2tool/go.mod

@@ -1,6 +1,8 @@
 module github.com/elastic/elastic-agent-client/v7/dev-tools/v2tool
 
-go 1.18
+go 1.21
+
+toolchain go1.21.1
 
 replace github.com/elastic/elastic-agent-client/v7 => ../../
 

dev-tools/v2tool/manager/manager.go

@@ -117,11 +117,11 @@ func newUnit(expected *proto.UnitExpectedConfig, rules RulesCfg) (Unit, error) {
 	return Unit{State: expectedStart, Rules: rules}, nil
 }
 
-// Checkin checkin is called every time the Mock V2 server performs a client checkin.
+// Checkin is called every time the Mock V2 server performs a client checkin.
 // It updates the units based on the current state, and returns a new expected config
 func (in *InputManager) Checkin(observed *proto.CheckinObserved, started time.Time) *proto.CheckinExpected {
 	base := &proto.CheckinExpected{
-		AgentInfo: &proto.CheckinAgentInfo{
+		AgentInfo: &proto.AgentInfo{
 			Id:       "test-agent",
 			Version:  "8.4.0",
 			Snapshot: true,
@@ -230,7 +230,7 @@ func generateUnitExpected(cfg *proto.UnitExpectedConfig) *proto.UnitExpected {
 // helper to form an entire CheckinExpected structure
 func createUnitsWithState(state proto.State, input *proto.UnitExpectedConfig, inID string, stateIndex uint64) *proto.CheckinExpected {
 	return &proto.CheckinExpected{
-		AgentInfo: &proto.CheckinAgentInfo{
+		AgentInfo: &proto.AgentInfo{
 			Id:       "test-agent",
 			Version:  "8.4.0",
 			Snapshot: true,

elastic-agent-client.proto

@@ -194,13 +194,16 @@ message UnitExpected {
     UnitLogLevel log_level = 6;
 }
 
-// Only provided on first checkin expected response to the component.
+// Agent information that the component might want to use for its events,
+// including the package version, which components should report instead
+// of their own version.
 //
-// Includes the agent information that the component might want to use for its events.
-message CheckinAgentInfo {
+// Sent on component start up as part of StartUpInfo and on the first checkin
+// expected response to the component.
+message AgentInfo {
     // ID is the Elastic Agent's unique ID.
     string id = 1;
-    // Version is the version of the running Elastic Agent.
+    // Version is the package version of the running Elastic Agent.
     string version = 2;
     // Snapshot is true when the running Elastic Agent is a snapshot version.
     bool snapshot = 3;
@@ -269,7 +272,7 @@ message CheckinExpected {
     // once their observed state has also been repoted as STOPPED to allow for graceful shutdown.
     repeated UnitExpected units = 1;
     // Agent info is provided only on first CheckinExpected response to the component.
-    CheckinAgentInfo agent_info = 2;
+    AgentInfo agent_info = 2;
 
     // Features are the expected feature flags configurations. Can apply to either components or
     // individual units depending on the flag and its implementation. Omitted if the client reports
@@ -323,10 +326,10 @@ message UnitObserved {
 message CheckinObservedVersionInfo {
     // Name of the binary.
     string name = 1;
-    // Version of the binary.
-    string version = 2;
     // Additional metadata about the binary.
     map<string, string> meta = 3;
+    // VCS commit hash of the binary.
+    string build_hash = 4;
 }
 
 // Observed statuses and configuration for defined units.
@@ -455,10 +458,12 @@ enum ConnInfoServices {
     Log = 4;
 }
 
-// Connection information sent to the application on startup so it knows how to connect back to the Elastic Agent.
+// Information sent to component on startup containing the necessary information
+// for the component to connect back to the Elastic Agent and the agent details.
 //
-// This is normally sent through stdin and should never be sent across a network un-encrypted.
-message ConnInfo {
+// This is normally sent through stdin and should never be sent across a network
+// un-encrypted.
+message StartUpInfo {
     // GRPC connection address.
     string addr = 1;
     // Server name to use when connecting over TLS.
@@ -475,6 +480,10 @@ message ConnInfo {
     repeated ConnInfoServices services = 7;
     // Supports provides information to the client about extra features this server supports.
     repeated ConnectionSupports supports = 8;
-    // Maximum message size that the client can use.
+    // Maximum message size that the client can use (in bytes).
     uint32 max_message_size = 9;
+    // Agent information, including the agent package version, which should be
+    // presented in user-visible fields and messages instead of the build
+    // version of the running component.
+    AgentInfo agent_info = 10;
 }

pkg/client/client_v2.go

@@ -17,14 +17,13 @@ import (
 	"sync"
 	"time"
 
-	"github.com/elastic/elastic-agent-client/v7/pkg/client/chunk"
-	"github.com/elastic/elastic-agent-libs/api/npipe"
-
 	"google.golang.org/grpc"
 	"google.golang.org/protobuf/types/known/timestamppb"
 
+	"github.com/elastic/elastic-agent-client/v7/pkg/client/chunk"
 	"github.com/elastic/elastic-agent-client/v7/pkg/proto"
 	"github.com/elastic/elastic-agent-client/v7/pkg/utils"
+	"github.com/elastic/elastic-agent-libs/api/npipe"
 )
 
 // DefaultMaxMessageSize is the maximum message size that is allowed to be sent.
@@ -150,10 +149,10 @@ type AgentInfo struct {
 type VersionInfo struct {
 	// Name is the name of the program.
 	Name string
-	// Version is the current version of the program.
-	Version string
 	// Meta is any extra metadata information about the version.
 	Meta map[string]string
+	// BuildHash is the VCS commit hash the program was built from.
+	BuildHash string
 }
 
 // V2 manages the state and communication to the Elastic Agent over the V2 control protocol.
@@ -192,6 +191,7 @@ type v2options struct {
 	maxMessageSize  int
 	chunkingAllowed bool
 	dialOptions     []grpc.DialOption
+	agentInfo       *AgentInfo
 }
 
 // DialOptions returns the dial options for the GRPC connection.
@@ -226,6 +226,14 @@ func WithGRPCDialOptions(opts ...grpc.DialOption) V2ClientOption {
 	}
 }
 
+// WithAgentInfo sets the AgentInfo and updates the client's VersionInfo.Version
+// to match the given agentInfo.Version.
+func WithAgentInfo(agentInfo AgentInfo) V2ClientOption {
+	return func(o *v2options) {
+		o.agentInfo = &agentInfo
+	}
+}
+
 // clientV2 manages the state and communication to the Elastic Agent over the V2 control protocol.
 type clientV2 struct {
 	target string
@@ -292,6 +300,7 @@ func NewV2(target string, token string, versionInfo VersionInfo, opts ...V2Clien
 	}
 
 	c := &clientV2{
+		agentInfo:             options.agentInfo,
 		target:                target,
 		opts:                  options,
 		token:                 token,
@@ -540,9 +549,9 @@ func (c *clientV2) sendObserved(client proto.ElasticAgent_CheckinV2Client) error
 	}
 	if !c.versionInfoSent {
 		msg.VersionInfo = &proto.CheckinObservedVersionInfo{
-			Name:    c.versionInfo.Name,
-			Version: c.versionInfo.Version,
-			Meta:    c.versionInfo.Meta,
+			Name:      c.versionInfo.Name,
+			Meta:      c.versionInfo.Meta,
+			BuildHash: c.versionInfo.BuildHash,
 		}
 		// supports information is sent when version information is set,
 		// this ensures that its always sent once per connected loop

pkg/client/client_v2_test.go

@@ -166,10 +166,9 @@ func testClientV2CheckinInitial(t *testing.T, localRPC string, serverCreds, clie
 			if observed.Token == token {
 				gotValid = true
 				reportedVersion.Name = observed.VersionInfo.Name
-				reportedVersion.Version = observed.VersionInfo.Version
 				reportedVersion.Meta = observed.VersionInfo.Meta
 				return &proto.CheckinExpected{
-					AgentInfo: &proto.CheckinAgentInfo{
+					AgentInfo: &proto.AgentInfo{
 						Id:       "elastic-agent-id",
 						Version:  "8.5.0",
 						Snapshot: true,
@@ -253,10 +252,8 @@ func testClientV2CheckinInitial(t *testing.T, localRPC string, serverCreds, clie
 	var errs2 []error
 	ctx, cancel = context.WithCancel(context.Background())
 	defer cancel()
-
 	validClient := NewV2(srv.GetTarget(), token, VersionInfo{
-		Name:    "program",
-		Version: "v1.0.0",
+		Name: "program",
 		Meta: map[string]string{
 			"key": "value",
 		},
@@ -325,7 +322,6 @@ func testClientV2CheckinInitial(t *testing.T, localRPC string, serverCreds, clie
 	assert.Equal(t, units[1].Type(), UnitTypeInput)
 
 	assert.Equal(t, reportedVersion.Name, "program")
-	assert.Equal(t, reportedVersion.Version, "v1.0.0")
 	assert.Equal(t, reportedVersion.Meta, map[string]string{
 		"key": "value",
 	})

pkg/client/reader.go

@@ -9,6 +9,7 @@ import (
 	"crypto/x509"
 	"errors"
 	"io"
+	"io/ioutil"
 
 	protobuf "github.com/golang/protobuf/proto"
 	"google.golang.org/grpc"
@@ -38,8 +39,8 @@ const (
 
 // NewFromReader creates a new client reading the connection information from the io.Reader.
 func NewFromReader(reader io.Reader, impl StateInterface, actions ...Action) (Client, error) {
-	connInfo := &proto.ConnInfo{}
-	data, err := io.ReadAll(reader)
+	connInfo := &proto.StartUpInfo{}
+	data, err := ioutil.ReadAll(reader)
 	if err != nil {
 		return nil, err
 	}
@@ -63,46 +64,55 @@ func NewFromReader(reader io.Reader, impl StateInterface, actions ...Action) (Cl
 
 // NewV2FromReader creates a new V2 client reading the connection information from the io.Reader.
 func NewV2FromReader(reader io.Reader, ver VersionInfo, opts ...V2ClientOption) (V2, []Service, error) {
-	connInfo := &proto.ConnInfo{}
+	info := &proto.StartUpInfo{}
 	data, err := io.ReadAll(reader)
 	if err != nil {
 		return nil, nil, err
 	}
-	err = protobuf.Unmarshal(data, connInfo)
+	err = protobuf.Unmarshal(data, info)
 	if err != nil {
 		return nil, nil, err
 	}
-	if connInfo.Services == nil {
+
+	if info.AgentInfo != nil {
+		opts = append(opts, WithAgentInfo(AgentInfo{
+			ID:       info.AgentInfo.Id,
+			Version:  info.AgentInfo.Version,
+			Snapshot: info.AgentInfo.Snapshot,
+		}))
+	}
+
+	if info.Services == nil {
 		return nil, []Service{ServiceCheckin}, ErrV2Unavailable
 	}
-	cert, err := tls.X509KeyPair(connInfo.PeerCert, connInfo.PeerKey)
+	cert, err := tls.X509KeyPair(info.PeerCert, info.PeerKey)
 	if err != nil {
 		return nil, nil, err
 	}
 	caCertPool := x509.NewCertPool()
-	caCertPool.AppendCertsFromPEM(connInfo.CaCert)
+	caCertPool.AppendCertsFromPEM(info.CaCert)
 	trans := credentials.NewTLS(&tls.Config{
-		ServerName:   connInfo.ServerName,
+		ServerName:   info.ServerName,
 		Certificates: []tls.Certificate{cert},
 		RootCAs:      caCertPool,
 	})
-	for _, s := range connInfo.Supports {
+	for _, s := range info.Supports {
 		if s == proto.ConnectionSupports_CheckinChunking {
 			opts = append(opts, WithChunking(true))
 		}
 	}
-	if connInfo.MaxMessageSize > 0 {
-		opts = append(opts, WithMaxMessageSize(int(connInfo.MaxMessageSize)))
+	if info.MaxMessageSize > 0 {
+		opts = append(opts, WithMaxMessageSize(int(info.MaxMessageSize)))
 	}
 	opts = append(opts, WithGRPCDialOptions(grpc.WithTransportCredentials(trans)))
 	client := NewV2(
-		connInfo.Addr,
-		connInfo.Token,
+		info.Addr,
+		info.Token,
 		ver,
 		opts...,
 	)
-	services := make([]Service, 0, len(connInfo.Services))
-	for _, srv := range connInfo.Services {
+	services := make([]Service, 0, len(info.Services))
+	for _, srv := range info.Services {
 		services = append(services, Service(srv))
 	}
 	return client, services, nil

pkg/client/reader_test.go

@@ -84,7 +84,7 @@ func TestNewFromReader_Connects(t *testing.T) {
 	require.NoError(t, srv.Start(grpc.Creds(creds)))
 	defer srv.Stop()
 
-	connInfo := &proto.ConnInfo{
+	connInfo := &proto.StartUpInfo{
 		Addr:       fmt.Sprintf(":%d", srv.Port),
 		ServerName: "localhost",
 		Token:      token,
@@ -131,7 +131,7 @@ func TestNewV2FromReader_Services(t *testing.T) {
 	caCertPool := x509.NewCertPool()
 	caCertPool.AppendCertsFromPEM(ca.caPEM)
 
-	connInfo := &proto.ConnInfo{
+	connInfo := &proto.StartUpInfo{
 		Addr:       ":7777",
 		ServerName: "localhost",
 		Token:      token,