Initial commit: Open sourcing all of the Maple Open Technologies code.

cloud/maplefile-backend/pkg/observability/metrics.go

@@ -0,0 +1,89 @@
+// codeberg.org/mapleopentech/monorepo/cloud/maplefile-backend/pkg/observability/metrics.go
+package observability
+
+import (
+	"fmt"
+	"net/http"
+	"runtime"
+	"time"
+
+	"go.uber.org/zap"
+)
+
+// MetricsServer provides basic metrics endpoint
+type MetricsServer struct {
+	logger    *zap.Logger
+	startTime time.Time
+}
+
+// NewMetricsServer creates a new metrics server
+func NewMetricsServer(logger *zap.Logger) *MetricsServer {
+	return &MetricsServer{
+		logger:    logger,
+		startTime: time.Now(),
+	}
+}
+
+// Handler returns an HTTP handler that serves basic metrics
+func (ms *MetricsServer) Handler() http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodGet {
+			http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
+			return
+		}
+
+		metrics := ms.collectMetrics()
+
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+		w.WriteHeader(http.StatusOK)
+
+		for _, metric := range metrics {
+			fmt.Fprintf(w, "%s\n", metric)
+		}
+	}
+}
+
+// collectMetrics collects basic application metrics
+func (ms *MetricsServer) collectMetrics() []string {
+	var m runtime.MemStats
+	runtime.ReadMemStats(&m)
+
+	uptime := time.Since(ms.startTime).Seconds()
+
+	metrics := []string{
+		fmt.Sprintf("# HELP mapleopentech_uptime_seconds Total uptime of the service in seconds"),
+		fmt.Sprintf("# TYPE mapleopentech_uptime_seconds counter"),
+		fmt.Sprintf("mapleopentech_uptime_seconds %.2f", uptime),
+
+		fmt.Sprintf("# HELP mapleopentech_memory_alloc_bytes Currently allocated memory in bytes"),
+		fmt.Sprintf("# TYPE mapleopentech_memory_alloc_bytes gauge"),
+		fmt.Sprintf("mapleopentech_memory_alloc_bytes %d", m.Alloc),
+
+		fmt.Sprintf("# HELP mapleopentech_memory_total_alloc_bytes Total allocated memory in bytes"),
+		fmt.Sprintf("# TYPE mapleopentech_memory_total_alloc_bytes counter"),
+		fmt.Sprintf("mapleopentech_memory_total_alloc_bytes %d", m.TotalAlloc),
+
+		fmt.Sprintf("# HELP mapleopentech_memory_sys_bytes Memory obtained from system in bytes"),
+		fmt.Sprintf("# TYPE mapleopentech_memory_sys_bytes gauge"),
+		fmt.Sprintf("mapleopentech_memory_sys_bytes %d", m.Sys),
+
+		fmt.Sprintf("# HELP mapleopentech_gc_runs_total Total number of GC runs"),
+		fmt.Sprintf("# TYPE mapleopentech_gc_runs_total counter"),
+		fmt.Sprintf("mapleopentech_gc_runs_total %d", m.NumGC),
+
+		fmt.Sprintf("# HELP mapleopentech_goroutines Current number of goroutines"),
+		fmt.Sprintf("# TYPE mapleopentech_goroutines gauge"),
+		fmt.Sprintf("mapleopentech_goroutines %d", runtime.NumGoroutine()),
+	}
+
+	return metrics
+}
+
+// RecordMetric records a custom metric (placeholder for future implementation)
+func (ms *MetricsServer) RecordMetric(name string, value float64, labels map[string]string) {
+	ms.logger.Debug("Recording metric",
+		zap.String("name", name),
+		zap.Float64("value", value),
+		zap.Any("labels", labels),
+	)
+}