Merge branch 'jc-add-praefect-optype-metric' into 'master'

Add praefect prometheus metric for method types

See merge request gitlab-org/gitaly!1835

2 files changed, 72 insertions, 0 deletions

diff --git a/internal/praefect/metrics/prometheus.go b/internal/praefect/metrics/prometheus.go
index fb53fe277..2a8981750 100644
--- a/internal/praefect/metrics/prometheus.go
+++ b/internal/praefect/metrics/prometheus.go
@@ -33,6 +33,27 @@ func RegisterReplicationJobsInFlight() (Gauge, error) {
 	return replicationJobsInFlight, prometheus.Register(replicationJobsInFlight)
 }
 
+var MethodTypeCounter = prometheus.NewCounterVec(
+	prometheus.CounterOpts{
+		Namespace: "gitaly",
+		Subsystem: "praefect",
+		Name:      "method_types",
+	}, []string{"method_type"},
+)
+
+var PrimaryGauge = prometheus.NewGaugeVec(
+	prometheus.GaugeOpts{
+		Namespace: "gitaly",
+		Subsystem: "praefect",
+		Name:      "primaries",
+	}, []string{"storage"},
+)
+
+func init() {
+	prometheus.MustRegister(MethodTypeCounter)
+	prometheus.MustRegister(PrimaryGauge)
+}
+
 // Gauge is a subset of a prometheus Gauge
 type Gauge interface {
 	Inc()
diff --git a/internal/praefect/middleware/methodtype.go b/internal/praefect/middleware/methodtype.go
new file mode 100644
index 000000000..6143ff7ba
--- /dev/null
+++ b/internal/praefect/middleware/methodtype.go
@@ -0,0 +1,51 @@
+package middleware
+
+import (
+	"context"
+
+	"github.com/sirupsen/logrus"
+	"gitlab.com/gitlab-org/gitaly/internal/praefect/metrics"
+	"gitlab.com/gitlab-org/gitaly/internal/praefect/protoregistry"
+	"google.golang.org/grpc"
+)
+
+// MethodTypeUnaryInterceptor returns a Unary Interceptor that records the method type of incoming RPC requests
+func MethodTypeUnaryInterceptor(r *protoregistry.Registry) grpc.UnaryServerInterceptor {
+	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
+		observeMethodType(r, info.FullMethod)
+
+		res, err := handler(ctx, req)
+
+		return res, err
+	}
+}
+
+// MethodTypeStreamInterceptor returns a Stream Interceptor that records the method type of incoming RPC requests
+func MethodTypeStreamInterceptor(r *protoregistry.Registry) grpc.StreamServerInterceptor {
+	return func(srv interface{}, stream grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
+		observeMethodType(r, info.FullMethod)
+
+		err := handler(srv, stream)
+
+		return err
+	}
+}
+
+func observeMethodType(registry *protoregistry.Registry, fullMethod string) {
+	mi, err := registry.LookupMethod(fullMethod)
+	if err != nil {
+		logrus.WithField("full_method_name", fullMethod).WithError(err).Warn("error when looking up method info")
+	}
+
+	var opType string
+	switch mi.Operation {
+	case protoregistry.OpAccessor:
+		opType = "accessor"
+	case protoregistry.OpMutator:
+		opType = "mutator"
+	default:
+		return
+	}
+
+	metrics.MethodTypeCounter.WithLabelValues(opType).Inc()
+}