peering: emit exported services count metric (#13811)

Signed-off-by: acpana <8968914+acpana@users.noreply.github.com>

agent/consul/leader_peering.go

@@ -8,6 +8,8 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/armon/go-metrics"
+	"github.com/armon/go-metrics/prometheus"
 	"github.com/hashicorp/go-hclog"
 	"github.com/hashicorp/go-memdb"
 	"github.com/hashicorp/go-multierror"
@@ -27,8 +29,72 @@ import (
 	"github.com/hashicorp/consul/proto/pbpeerstream"
 )
 
+var leaderExportedServicesCountKey = []string{"consul", "peering", "exported_services"}
+var LeaderPeeringMetrics = []prometheus.GaugeDefinition{
+	{
+		Name: leaderExportedServicesCountKey,
+		Help: "A gauge that tracks how many services are exported for the peering. " +
+			"The labels are \"peering\" and, for enterprise, \"partition\". " +
+			"We emit this metric every 9 seconds",
+	},
+}
+
 func (s *Server) startPeeringStreamSync(ctx context.Context) {
 	s.leaderRoutineManager.Start(ctx, peeringStreamsRoutineName, s.runPeeringSync)
+	s.leaderRoutineManager.Start(ctx, peeringStreamsMetricsRoutineName, s.runPeeringMetrics)
+}
+
+func (s *Server) runPeeringMetrics(ctx context.Context) error {
+	ticker := time.NewTicker(s.config.MetricsReportingInterval)
+	defer ticker.Stop()
+
+	logger := s.logger.Named(logging.PeeringMetrics)
+	defaultMetrics := metrics.Default
+
+	for {
+		select {
+		case <-ctx.Done():
+			logger.Info("stopping peering metrics")
+
+			// "Zero-out" the metric on exit so that when prometheus scrapes this
+			// metric from a non-leader, it does not get a stale value.
+			metrics.SetGauge(leaderExportedServicesCountKey, float32(0))
+			return nil
+		case <-ticker.C:
+			if err := s.emitPeeringMetricsOnce(logger, defaultMetrics()); err != nil {
+				s.logger.Error("error emitting peering stream metrics", "error", err)
+			}
+		}
+	}
+}
+
+func (s *Server) emitPeeringMetricsOnce(logger hclog.Logger, metricsImpl *metrics.Metrics) error {
+	_, peers, err := s.fsm.State().PeeringList(nil, *structs.NodeEnterpriseMetaInPartition(structs.WildcardSpecifier))
+	if err != nil {
+		return err
+	}
+
+	for _, peer := range peers {
+		status, found := s.peerStreamServer.StreamStatus(peer.ID)
+		if !found {
+			logger.Trace("did not find status for", "peer_name", peer.Name)
+			continue
+		}
+
+		esc := status.GetExportedServicesCount()
+		part := peer.Partition
+		labels := []metrics.Label{
+			{Name: "peer_name", Value: peer.Name},
+			{Name: "peer_id", Value: peer.ID},
+		}
+		if part != "" {
+			labels = append(labels, metrics.Label{Name: "partition", Value: part})
+		}
+
+		metricsImpl.SetGaugeWithLabels(leaderExportedServicesCountKey, float32(esc), labels)
+	}
+
+	return nil
 }
 
 func (s *Server) runPeeringSync(ctx context.Context) error {
@@ -51,6 +117,7 @@ func (s *Server) runPeeringSync(ctx context.Context) error {
 func (s *Server) stopPeeringStreamSync() {
 	// will be a no-op when not started
 	s.leaderRoutineManager.Stop(peeringStreamsRoutineName)
+	s.leaderRoutineManager.Stop(peeringStreamsMetricsRoutineName)
 }
 
 // syncPeeringsAndBlock is a long-running goroutine that is responsible for watching

agent/consul/leader_peering_test.go

@@ -4,10 +4,12 @@ import (
 	"context"
 	"encoding/base64"
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"testing"
 	"time"
 
+	"github.com/armon/go-metrics"
 	"github.com/stretchr/testify/require"
 	"google.golang.org/grpc"
 
@@ -615,7 +617,7 @@ func insertTestPeeringData(t *testing.T, store *state.Store, peer string, lastId
 	return lastIdx
 }
 
-// TODO(peering): once we move away from leader only request for PeeringList, move this test to consul/server_test maybe
+// TODO(peering): once we move away from keeping state in stream tracker only on leaders, move this test to consul/server_test maybe
 func TestLeader_Peering_ImportedExportedServicesCount(t *testing.T) {
 	if testing.Short() {
 		t.Skip("too slow for testing.Short")
@@ -904,3 +906,133 @@ func TestLeader_Peering_ImportedExportedServicesCount(t *testing.T) {
 		})
 	}
 }
+
+// TODO(peering): once we move away from keeping state in stream tracker only on leaders, move this test to consul/server_test maybe
+func TestLeader_PeeringMetrics_emitPeeringMetrics(t *testing.T) {
+	if testing.Short() {
+		t.Skip("too slow for testing.Short")
+	}
+
+	var (
+		s2PeerID1          = generateUUID()
+		s2PeerID2          = generateUUID()
+		testContextTimeout = 60 * time.Second
+		lastIdx            = uint64(0)
+	)
+
+	// TODO(peering): Configure with TLS
+	_, s1 := testServerWithConfig(t, func(c *Config) {
+		c.NodeName = "s1.dc1"
+		c.Datacenter = "dc1"
+		c.TLSConfig.Domain = "consul"
+	})
+	testrpc.WaitForLeader(t, s1.RPC, "dc1")
+
+	// Create a peering by generating a token
+	ctx, cancel := context.WithTimeout(context.Background(), testContextTimeout)
+	t.Cleanup(cancel)
+
+	conn, err := grpc.DialContext(ctx, s1.config.RPCAddr.String(),
+		grpc.WithContextDialer(newServerDialer(s1.config.RPCAddr.String())),
+		grpc.WithInsecure(),
+		grpc.WithBlock())
+	require.NoError(t, err)
+	defer conn.Close()
+
+	peeringClient := pbpeering.NewPeeringServiceClient(conn)
+
+	req := pbpeering.GenerateTokenRequest{
+		PeerName: "my-peer-s2",
+	}
+	resp, err := peeringClient.GenerateToken(ctx, &req)
+	require.NoError(t, err)
+
+	tokenJSON, err := base64.StdEncoding.DecodeString(resp.PeeringToken)
+	require.NoError(t, err)
+
+	var token structs.PeeringToken
+	require.NoError(t, json.Unmarshal(tokenJSON, &token))
+
+	// Bring up s2 and store s1's token so that it attempts to dial.
+	_, s2 := testServerWithConfig(t, func(c *Config) {
+		c.NodeName = "s2.dc2"
+		c.Datacenter = "dc2"
+		c.PrimaryDatacenter = "dc2"
+	})
+	testrpc.WaitForLeader(t, s2.RPC, "dc2")
+
+	// Simulate exporting services in the tracker
+	{
+		// Simulate a peering initiation event by writing a peering with data from a peering token.
+		// Eventually the leader in dc2 should dial and connect to the leader in dc1.
+		p := &pbpeering.Peering{
+			ID:                  s2PeerID1,
+			Name:                "my-peer-s1",
+			PeerID:              token.PeerID,
+			PeerCAPems:          token.CA,
+			PeerServerName:      token.ServerName,
+			PeerServerAddresses: token.ServerAddresses,
+		}
+		require.True(t, p.ShouldDial())
+		lastIdx++
+		require.NoError(t, s2.fsm.State().PeeringWrite(lastIdx, p))
+
+		p2 := &pbpeering.Peering{
+			ID:                  s2PeerID2,
+			Name:                "my-peer-s3",
+			PeerID:              token.PeerID, // doesn't much matter what these values are
+			PeerCAPems:          token.CA,
+			PeerServerName:      token.ServerName,
+			PeerServerAddresses: token.ServerAddresses,
+		}
+		require.True(t, p2.ShouldDial())
+		lastIdx++
+		require.NoError(t, s2.fsm.State().PeeringWrite(lastIdx, p2))
+
+		// connect the stream
+		mst1, err := s2.peeringServer.Tracker.Connected(s2PeerID1)
+		require.NoError(t, err)
+
+		// mimic tracking exported services
+		mst1.TrackExportedService(structs.ServiceName{Name: "a-service"})
+		mst1.TrackExportedService(structs.ServiceName{Name: "b-service"})
+		mst1.TrackExportedService(structs.ServiceName{Name: "c-service"})
+
+		// connect the stream
+		mst2, err := s2.peeringServer.Tracker.Connected(s2PeerID2)
+		require.NoError(t, err)
+
+		// mimic tracking exported services
+		mst2.TrackExportedService(structs.ServiceName{Name: "d-service"})
+		mst2.TrackExportedService(structs.ServiceName{Name: "e-service"})
+	}
+
+	// set up a metrics sink
+	sink := metrics.NewInmemSink(testContextTimeout, testContextTimeout)
+	cfg := metrics.DefaultConfig("us-west")
+	cfg.EnableHostname = false
+	met, err := metrics.New(cfg, sink)
+	require.NoError(t, err)
+
+	errM := s2.emitPeeringMetricsOnce(s2.logger, met)
+	require.NoError(t, errM)
+
+	retry.Run(t, func(r *retry.R) {
+		intervals := sink.Data()
+		require.Len(r, intervals, 1)
+		intv := intervals[0]
+
+		// the keys for a Gauge value look like: {serviceName}.{prefix}.{key_name};{label=value};...
+		keyMetric1 := fmt.Sprintf("us-west.consul.peering.exported_services;peer_name=my-peer-s1;peer_id=%s", s2PeerID1)
+		metric1, ok := intv.Gauges[keyMetric1]
+		require.True(r, ok, fmt.Sprintf("did not find the key %q", keyMetric1))
+
+		require.Equal(r, float32(3), metric1.Value) // for a, b, c services
+
+		keyMetric2 := fmt.Sprintf("us-west.consul.peering.exported_services;peer_name=my-peer-s3;peer_id=%s", s2PeerID2)
+		metric2, ok := intv.Gauges[keyMetric2]
+		require.True(r, ok, fmt.Sprintf("did not find the key %q", keyMetric2))
+
+		require.Equal(r, float32(2), metric2.Value) // for d, e services
+	})
+}

agent/consul/server.go

@@ -127,6 +127,7 @@ const (
 	virtualIPCheckRoutineName             = "virtual IP version check"
 	peeringStreamsRoutineName             = "streaming peering resources"
 	peeringDeletionRoutineName            = "peering deferred deletion"
+	peeringStreamsMetricsRoutineName      = "metrics for streaming peering resources"
 )
 
 var (

agent/grpc-external/services/peerstream/stream_resources.go

@@ -539,8 +539,8 @@ func getTrustDomain(store StateStore, logger hclog.Logger) (string, error) {
 	return connect.SpiffeIDSigningForCluster(cfg.ClusterID).Host(), nil
 }
 
-func (s *Server) StreamStatus(peer string) (resp Status, found bool) {
-	return s.Tracker.StreamStatus(peer)
+func (s *Server) StreamStatus(peerID string) (resp Status, found bool) {
+	return s.Tracker.StreamStatus(peerID)
 }
 
 // ConnectedStreams returns a map of connected stream IDs to the corresponding channel for tearing them down.

agent/setup.go

@@ -231,7 +231,8 @@ func getPrometheusDefs(cfg lib.TelemetryConfig, isServer bool) ([]prometheus.Gau
 	if isServer {
 		gauges = append(gauges,
 			consul.AutopilotGauges,
-			consul.LeaderCertExpirationGauges)
+			consul.LeaderCertExpirationGauges,
+			consul.LeaderPeeringMetrics)
 	}
 
 	// Flatten definitions

logging/names.go

@@ -51,6 +51,7 @@ const (
 	Snapshot           string = "snapshot"
 	Partition          string = "partition"
 	Peering            string = "peering"
+	PeeringMetrics     string = "peering_metrics"
 	TerminatingGateway string = "terminating_gateway"
 	TLSUtil            string = "tlsutil"
 	Transaction        string = "txn"