[hw-7] add metrics, tracing

loms/internal/infra/grpc/metrics/db.go

@@ -0,0 +1,31 @@
+package metrics
+
+import (
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var (
+	dbQueryCounter = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: "app",
+		Name:      "db_queries_total",
+		Help:      "Total DB queries",
+	}, []string{"category", "error"})
+
+	dbQueryDurationHistogram = promauto.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "app",
+		Name:      "db_query_duration_seconds",
+		Help:      "Latency of DB queries, seconds",
+		Buckets:   prometheus.DefBuckets,
+	}, []string{"category", "error"})
+)
+
+func IncDBQueryCount(cat, errLabel string) {
+	dbQueryCounter.WithLabelValues(cat, errLabel).Inc()
+}
+
+func StoreDBQueryDuration(cat, errLabel string, d time.Duration) {
+	dbQueryDurationHistogram.WithLabelValues(cat, errLabel).Observe(d.Seconds())
+}

loms/internal/infra/grpc/metrics/metrics.go

@@ -0,0 +1,31 @@
+package metrics
+
+import (
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var (
+	requestCounter = promauto.NewCounterVec(prometheus.CounterOpts{
+		Namespace: "app",
+		Name:      "requests_total",
+		Help:      "Total amount of request by handler",
+	}, []string{"method", "path", "status_code"})
+
+	requestDurationHistogram = promauto.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: "app",
+		Name:      "request_duration_seconds",
+		Help:      "Latency of handler processing, seconds",
+		Buckets:   prometheus.DefBuckets,
+	}, []string{"method", "path", "status_code"})
+)
+
+func IncRequestHandlerCount(method, path, statusCode string) {
+	requestCounter.WithLabelValues(method, path, statusCode).Inc()
+}
+
+func StoreHandlerRequestDuration(method, path, statusCode string, d time.Duration) {
+	requestDurationHistogram.WithLabelValues(method, path, statusCode).Observe(d.Seconds())
+}

loms/internal/infra/grpc/middleware/metrics.go

@@ -0,0 +1,43 @@
+package mw
+
+import (
+	"context"
+	"strings"
+	"time"
+
+	"route256/loms/internal/infra/grpc/metrics"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/status"
+)
+
+const UNKNOWN = "unknown"
+
+func WithMetrics(ctx context.Context, req any, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp any, err error) {
+	start := time.Now()
+
+	resp, err = handler(ctx, req)
+
+	// "/pkg.Service/Method"
+	service, method := parseFullMethod(info.FullMethod)
+
+	code := status.Code(err).String()
+
+	metrics.IncRequestHandlerCount(service, method, code)
+	metrics.StoreHandlerRequestDuration(service, method, code, time.Since(start))
+
+	return resp, err
+}
+
+func parseFullMethod(full string) (service, method string) {
+	if full == "" {
+		return UNKNOWN, UNKNOWN
+	}
+	full = strings.TrimPrefix(full, "/")
+
+	slash := strings.Index(full, "/")
+	if slash < 0 {
+		return full, UNKNOWN
+	}
+	return full[:slash], full[slash+1:]
+}

loms/internal/infra/grpc/middleware/tracing.go

@@ -0,0 +1,38 @@
+package mw
+
+import (
+	"context"
+	"strings"
+
+	"go.opentelemetry.io/otel/codes"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/status"
+
+	"route256/loms/internal/infra/tracing"
+)
+
+func WithTracing(ctx context.Context, req any, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (any, error) {
+	service, method := splitFullMethod(info.FullMethod)
+	ctx, span := tracing.Tracer().Start(ctx, service+"/"+method)
+	defer span.End()
+
+	resp, err := handler(ctx, req)
+
+	if err != nil {
+		span.RecordError(err)
+		span.SetStatus(codes.Error, status.Convert(err).Message())
+	} else {
+		span.SetStatus(codes.Ok, "OK")
+	}
+
+	return resp, err
+}
+
+func splitFullMethod(full string) (service, method string) {
+	full = strings.TrimPrefix(full, "/")
+	if i := strings.Index(full, "/"); i >= 0 {
+		return full[:i], full[i+1:]
+	}
+
+	return "unknown", full
+}