Move runtime metrics monitoring code to a separate place

Move runtime metrics monitoring code to a separate place

src/checkoutservice/main.go

@@ -10,13 +10,10 @@ import (
 	"net"
 	"net/http"
 	"os"
-	goruntime "runtime"
 	"strconv"
 	"sync"
 	"time"
 
-	"go.opentelemetry.io/otel/metric"
-
 	"go.opentelemetry.io/otel/attribute"
 	semconv "go.opentelemetry.io/otel/semconv/v1.24.0"
 	"go.opentelemetry.io/otel/trace"
@@ -617,39 +614,3 @@ func (cs *checkoutService) getIntFeatureFlag(ctx context.Context, featureFlagNam
 
 	return int(featureFlagValue)
 }
-
-func recordRuntimeMetrics(meter metric.Meter) error {
-	// Create metric instruments
-	gcPause, err := meter.Float64ObservableGauge("go_gc_pause")
-	if err != nil {
-		return err
-	}
-
-	allocatedMemory, err := meter.Float64ObservableGauge("go_allocated_memory")
-	if err != nil {
-		return err
-	}
-
-	memoryObtainedFromSystem, err := meter.Float64ObservableGauge("go_memory_obtained_from_system")
-	if err != nil {
-		return err
-	}
-
-	// Record the runtime stats periodically
-	if _, err := meter.RegisterCallback(
-		func(ctx context.Context, o metric.Observer) error {
-			var memStats goruntime.MemStats
-			goruntime.ReadMemStats(&memStats)
-
-			o.ObserveFloat64(gcPause, float64(memStats.PauseTotalNs)/1e6)     // GC Pause in ms
-			o.ObserveFloat64(allocatedMemory, float64(memStats.Alloc))        // Allocated Memory in B
-			o.ObserveFloat64(memoryObtainedFromSystem, float64(memStats.Sys)) // Memory Obtained From System in B
-			return nil
-		},
-		gcPause, allocatedMemory, memoryObtainedFromSystem,
-	); err != nil {
-		return err
-	}
-
-	return nil
-}

src/checkoutservice/runtimeMetrics.go

@@ -0,0 +1,46 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+package main
+
+import (
+	"context"
+	"runtime"
+
+	"go.opentelemetry.io/otel/metric"
+)
+
+func recordRuntimeMetrics(meter metric.Meter) error {
+	// Create metric instruments
+	gcPause, err := meter.Float64ObservableGauge("go_gc_pause")
+	if err != nil {
+		return err
+	}
+
+	allocatedMemory, err := meter.Float64ObservableGauge("go_allocated_memory")
+	if err != nil {
+		return err
+	}
+
+	memoryObtainedFromSystem, err := meter.Float64ObservableGauge("go_memory_obtained_from_system")
+	if err != nil {
+		return err
+	}
+
+	// Record the runtime stats periodically
+	if _, err := meter.RegisterCallback(
+		func(ctx context.Context, o metric.Observer) error {
+			var memStats runtime.MemStats
+			runtime.ReadMemStats(&memStats)
+
+			o.ObserveFloat64(gcPause, float64(memStats.PauseTotalNs)/1e6)     // GC Pause in ms
+			o.ObserveFloat64(allocatedMemory, float64(memStats.Alloc))        // Allocated Memory in B
+			o.ObserveFloat64(memoryObtainedFromSystem, float64(memStats.Sys)) // Memory Obtained From System in B
+			return nil
+		},
+		gcPause, allocatedMemory, memoryObtainedFromSystem,
+	); err != nil {
+		return err
+	}
+
+	return nil
+}