feat(go): expose runtime ingest metrics

go/vehicle-gateway/cmd/stat-writer/main_test.go

@@ -3,11 +3,13 @@ package main
 import (
 	"context"
 	"encoding/json"
+	"strings"
 	"testing"
 
 	"github.com/segmentio/kafka-go"
 
 	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/metrics"
 )
 
 func TestProcessStatMessageUsesUncancelledContextForAppendAndCommit(t *testing.T) {
@@ -29,7 +31,7 @@ func TestProcessStatMessageUsesUncancelledContextForAppendAndCommit(t *testing.T
 	appender := &contextCheckingStatAppender{}
 	committer := &contextCheckingStatCommitter{}
 
-	processStatMessage(parent, discardStatLogger{}, appender, committer, kafka.Message{Value: payload})
+	processStatMessage(parent, discardStatLogger{}, nil, appender, committer, kafka.Message{Value: payload})
 
 	if appender.ctxErr != nil {
 		t.Fatalf("appender saw cancelled context: %v", appender.ctxErr)
@@ -42,6 +44,35 @@ func TestProcessStatMessageUsesUncancelledContextForAppendAndCommit(t *testing.T
 	}
 }
 
+func TestProcessStatMessageRecordsMetrics(t *testing.T) {
+	env := envelope.FrameEnvelope{Protocol: envelope.ProtocolJT808, Phone: "13307795425", MessageID: "0x0200"}
+	payload, err := json.Marshal(env)
+	if err != nil {
+		t.Fatal(err)
+	}
+	registry := metrics.NewRegistry()
+
+	processStatMessage(
+		context.Background(),
+		discardStatLogger{},
+		registry,
+		&contextCheckingStatAppender{},
+		&contextCheckingStatCommitter{},
+		kafka.Message{Topic: "vehicle.raw.jt808.v1", Value: payload},
+	)
+
+	text := registry.Render()
+	for _, want := range []string{
+		`vehicle_stat_kafka_messages_total{status="received",topic="vehicle.raw.jt808.v1"} 1`,
+		`vehicle_stat_writes_total{status="ok",topic="vehicle.raw.jt808.v1"} 1`,
+		`vehicle_stat_kafka_commits_total{status="ok",topic="vehicle.raw.jt808.v1"} 1`,
+	} {
+		if !strings.Contains(text, want) {
+			t.Fatalf("metrics missing %s:\n%s", want, text)
+		}
+	}
+}
+
 type contextCheckingStatAppender struct {
 	ctxErr error
 	count  int