Emit metrics for MLS sent messages (#355)

* feat: emit metrics for mls sent messages

* Fix lint errors 👮

dev/run

@@ -14,7 +14,7 @@ go run cmd/xmtpd/main.go \
     --store.db-connection-string "${MESSAGE_DB_DSN}" \
     --store.reader-db-connection-string "${MESSAGE_DB_DSN}" \
     --store.metrics-period 5s \
-    --mls-store.db-connection-string "${MESSAGE_DB_DSN}" \
+    --mls-store.db-connection-string "${MLS_DB_DSN}" \
     --authz-db-connection-string "${AUTHZ_DB_DSN}" \
     --go-profiling \
     "$@"

pkg/metrics/metrics.go

@@ -66,6 +66,10 @@ func registerCollectors(reg prometheus.Registerer) {
 		queryResultLength,
 		ratelimiterBuckets,
 		ratelimiterBucketsDeleted,
+		mlsSentGroupMessageSize,
+		mlsSentGroupMessageCount,
+		mlsSentWelcomeMessageSize,
+		mlsSentWelcomeMessageCount,
 	}
 	for _, col := range cols {
 		reg.MustRegister(col)

pkg/metrics/mls.go

@@ -0,0 +1,55 @@
+package metrics
+
+import (
+	"context"
+
+	"github.com/prometheus/client_golang/prometheus"
+	mlsstore "github.com/xmtp/xmtp-node-go/pkg/mls/store"
+	"go.uber.org/zap"
+)
+
+var mlsSentGroupMessageSize = prometheus.NewHistogramVec(
+	prometheus.HistogramOpts{
+		Name:    "mls_sent_group_message_size",
+		Help:    "Size of a sent group message in bytes",
+		Buckets: []float64{100, 1000, 10000, 100000},
+	},
+	appClientVersionTagKeys,
+)
+
+var mlsSentGroupMessageCount = prometheus.NewCounterVec(
+	prometheus.CounterOpts{
+		Name: "mls_sent_group_messages",
+		Help: "Count of sent group messages",
+	},
+	appClientVersionTagKeys,
+)
+
+func EmitMLSSentGroupMessage(ctx context.Context, log *zap.Logger, msg *mlsstore.GroupMessage) {
+	labels := contextLabels(ctx)
+	mlsSentGroupMessageSize.With(labels).Observe(float64(len(msg.Data)))
+	mlsSentGroupMessageCount.With(labels).Inc()
+}
+
+var mlsSentWelcomeMessageSize = prometheus.NewHistogramVec(
+	prometheus.HistogramOpts{
+		Name:    "mls_sent_welcome_message_size",
+		Help:    "Size of a sent welcome message in bytes",
+		Buckets: []float64{100, 1000, 10000, 100000},
+	},
+	appClientVersionTagKeys,
+)
+
+var mlsSentWelcomeMessageCount = prometheus.NewCounterVec(
+	prometheus.CounterOpts{
+		Name: "mls_sent_welcome_messages",
+		Help: "Count of sent welcome messages",
+	},
+	appClientVersionTagKeys,
+)
+
+func EmitMLSSentWelcomeMessage(ctx context.Context, log *zap.Logger, msg *mlsstore.WelcomeMessage) {
+	labels := contextLabels(ctx)
+	mlsSentWelcomeMessageSize.With(labels).Observe(float64(len(msg.Data)))
+	mlsSentWelcomeMessageCount.With(labels).Inc()
+}

pkg/mls/api/v1/service.go

@@ -12,6 +12,7 @@ import (
 	"github.com/nats-io/nats-server/v2/server"
 	"github.com/nats-io/nats.go"
 	wakupb "github.com/waku-org/go-waku/waku/v2/protocol/pb"
+	"github.com/xmtp/xmtp-node-go/pkg/metrics"
 	mlsstore "github.com/xmtp/xmtp-node-go/pkg/mls/store"
 	"github.com/xmtp/xmtp-node-go/pkg/mlsvalidate"
 	mlsv1 "github.com/xmtp/xmtp-node-go/pkg/proto/mls/api/v1"
@@ -299,12 +300,15 @@ func (s *Service) SendGroupMessages(ctx context.Context, req *mlsv1.SendGroupMes
 			return nil, err
 		}
 		log.Info("published to waku relay", zap.String("contentTopic", contentTopic))
+
+		metrics.EmitMLSSentGroupMessage(ctx, log, msg)
 	}
 
 	return &emptypb.Empty{}, nil
 }
 
 func (s *Service) SendWelcomeMessages(ctx context.Context, req *mlsv1.SendWelcomeMessagesRequest) (res *emptypb.Empty, err error) {
+	log := s.log.Named("send-welcome-messages")
 	if err = validateSendWelcomeMessagesRequest(req); err != nil {
 		return nil, err
 	}
@@ -342,6 +346,8 @@ func (s *Service) SendWelcomeMessages(ctx context.Context, req *mlsv1.SendWelcom
 		if err != nil {
 			return nil, err
 		}
+
+		metrics.EmitMLSSentWelcomeMessage(ctx, log, msg)
 	}
 	return &emptypb.Empty{}, nil
 }