Prepare v0.5.1

Support both Unix epoch timestamps and RFC3339 format for build time
injection via ldflags. Unix epoch format provides simpler build
commands: $(date +%s) vs $(date -u +%Y-%m-%dT%H:%M:%SZ).

- Add parseBuildTime() to convert epoch to RFC3339
- Maintain backward compatibility with existing RFC3339 format
- Ensure consistent RFC3339 output regardless of input format
- Fix build date priority over git commit time

CHANGELOG.md

@@ -0,0 +1,34 @@
+# Release Notes - v0.5.1
+
+## Observability Enhancements
+
+### OTLP Metrics Support
+- **New `metrics/` package** - OpenTelemetry-native metrics with OTLP export support for structured metrics collection
+- **Centralized OTLP configuration** - Refactored configuration to `internal/tracerconfig/` to eliminate code duplication across tracing, logging, and metrics
+- **HTTP retry support** - Added consistent retry configuration for all HTTP OTLP exporters to improve reliability
+
+### Enhanced Logging
+- **Buffering exporter** - Added OTLP log buffering to queue logs until tracing configuration is available
+- **TLS support for logs** - Client certificate authentication support for secure OTLP log export
+- **Improved logfmt formatting** - Better structured output for log messages
+
+### Tracing Improvements
+- **HTTP retry support** - OTLP trace requests now automatically retry on failure when using HTTP transport
+
+## Build System
+
+### Version Package Enhancements
+- **Unix epoch build time support** - Build time can now be injected as Unix timestamps (`$(date +%s)`) in addition to RFC3339 format
+- **Simplified build commands** - Reduces complexity of ldflags injection while maintaining backward compatibility
+- **Consistent output format** - All build times normalize to RFC3339 format regardless of input
+
+## API Changes
+
+### New Public Interfaces
+- `metrics.NewMeterProvider()` - Create OTLP metrics provider with centralized configuration
+- `metrics.Shutdown()` - Graceful shutdown for metrics exporters
+- `internal/tracerconfig` - Shared OTLP configuration utilities (internal package)
+
+### Dependencies
+- Added explicit OpenTelemetry metrics dependencies to `go.mod`
+- Updated tracing dependencies for retry support

go.mod

@@ -19,12 +19,18 @@ require (
 	go.opentelemetry.io/contrib/exporters/autoexport v0.58.0
 	go.opentelemetry.io/contrib/instrumentation/github.com/labstack/echo/otelecho v0.58.0
 	go.opentelemetry.io/otel v1.33.0
+	go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc v0.9.0
+	go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp v0.9.0
+	go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc v1.33.0
+	go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp v1.33.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.33.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.33.0
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.33.0
 	go.opentelemetry.io/otel/log v0.9.0
+	go.opentelemetry.io/otel/metric v1.33.0
 	go.opentelemetry.io/otel/sdk v1.33.0
 	go.opentelemetry.io/otel/sdk/log v0.9.0
+	go.opentelemetry.io/otel/sdk/metric v1.33.0
 	go.opentelemetry.io/otel/trace v1.33.0
 	golang.org/x/mod v0.22.0
 	golang.org/x/net v0.33.0
@@ -59,16 +65,10 @@ require (
 	github.com/valyala/fasttemplate v1.2.2 // indirect
 	go.opentelemetry.io/auto/sdk v1.1.0 // indirect
 	go.opentelemetry.io/contrib/bridges/prometheus v0.58.0 // indirect
-	go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc v0.9.0 // indirect
-	go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp v0.9.0 // indirect
-	go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc v1.33.0 // indirect
-	go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp v1.33.0 // indirect
 	go.opentelemetry.io/otel/exporters/prometheus v0.55.0 // indirect
 	go.opentelemetry.io/otel/exporters/stdout/stdoutlog v0.9.0 // indirect
 	go.opentelemetry.io/otel/exporters/stdout/stdoutmetric v1.33.0 // indirect
 	go.opentelemetry.io/otel/exporters/stdout/stdouttrace v1.33.0 // indirect
-	go.opentelemetry.io/otel/metric v1.33.0 // indirect
-	go.opentelemetry.io/otel/sdk/metric v1.33.0 // indirect
 	go.opentelemetry.io/proto/otlp v1.4.0 // indirect
 	golang.org/x/crypto v0.31.0 // indirect
 	golang.org/x/sys v0.28.0 // indirect

internal/tracerconfig/config.go

@@ -0,0 +1,378 @@
+// Package tracerconfig provides a bridge to eliminate circular dependencies between
+// the logger and tracing packages. It stores tracer configuration and provides
+// factory functions that can be used by the logger package without importing tracing.
+package tracerconfig
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"net/url"
+	"os"
+	"strings"
+	"sync"
+	"time"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc"
+	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp"
+	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
+	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
+	sdklog "go.opentelemetry.io/otel/sdk/log"
+	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+	"google.golang.org/grpc/credentials"
+)
+
+const (
+	otelExporterOTLPProtoEnvKey        = "OTEL_EXPORTER_OTLP_PROTOCOL"
+	otelExporterOTLPTracesProtoEnvKey  = "OTEL_EXPORTER_OTLP_TRACES_PROTOCOL"
+	otelExporterOTLPLogsProtoEnvKey    = "OTEL_EXPORTER_OTLP_LOGS_PROTOCOL"
+	otelExporterOTLPMetricsProtoEnvKey = "OTEL_EXPORTER_OTLP_METRICS_PROTOCOL"
+)
+
+var errInvalidOTLPProtocol = errors.New("invalid OTLP protocol - should be one of ['grpc', 'http/protobuf']")
+
+// newInvalidProtocolError creates a specific error message for invalid protocols
+func newInvalidProtocolError(protocol, signalType string) error {
+	return fmt.Errorf("invalid OTLP protocol '%s' for %s - should be one of ['grpc', 'http/protobuf', 'http/json']", protocol, signalType)
+}
+
+// Validate checks the configuration for common errors and inconsistencies
+func (c *Config) Validate() error {
+	var errs []error
+
+	// Check that both Endpoint and EndpointURL are not specified
+	if c.Endpoint != "" && c.EndpointURL != "" {
+		errs = append(errs, errors.New("cannot specify both Endpoint and EndpointURL - use one or the other"))
+	}
+
+	// Validate EndpointURL format if specified
+	if c.EndpointURL != "" {
+		if _, err := url.Parse(c.EndpointURL); err != nil {
+			errs = append(errs, fmt.Errorf("invalid EndpointURL format: %w", err))
+		}
+	}
+
+	// Validate Endpoint format if specified
+	if c.Endpoint != "" {
+		// Basic validation - should not contain protocol scheme
+		if strings.Contains(c.Endpoint, "://") {
+			errs = append(errs, errors.New("Endpoint should not include protocol scheme (use EndpointURL for full URLs)"))
+		}
+		// Should not be empty after trimming whitespace
+		if strings.TrimSpace(c.Endpoint) == "" {
+			errs = append(errs, errors.New("Endpoint cannot be empty or whitespace"))
+		}
+	}
+
+	// Validate TLS configuration consistency
+	if c.CertificateProvider != nil && c.RootCAs == nil {
+		// This is just a warning - client cert without custom CAs is valid
+		// but might indicate a configuration issue
+	}
+
+	// Validate service name if specified
+	if c.ServiceName != "" && strings.TrimSpace(c.ServiceName) == "" {
+		errs = append(errs, errors.New("ServiceName cannot be empty or whitespace"))
+	}
+
+	// Combine all errors
+	if len(errs) > 0 {
+		var errMsgs []string
+		for _, err := range errs {
+			errMsgs = append(errMsgs, err.Error())
+		}
+		return fmt.Errorf("configuration validation failed: %s", strings.Join(errMsgs, "; "))
+	}
+
+	return nil
+}
+
+// ValidateAndStore validates the configuration before storing it
+func ValidateAndStore(ctx context.Context, cfg *Config, logFactory LogExporterFactory, metricFactory MetricExporterFactory, traceFactory TraceExporterFactory) error {
+	if cfg != nil {
+		if err := cfg.Validate(); err != nil {
+			return err
+		}
+	}
+	Store(ctx, cfg, logFactory, metricFactory, traceFactory)
+	return nil
+}
+
+// GetClientCertificate defines a function type for providing client certificates for mutual TLS.
+// This is used when exporting telemetry data to secured OTLP endpoints that require
+// client certificate authentication.
+type GetClientCertificate func(*tls.CertificateRequestInfo) (*tls.Certificate, error)
+
+// Config provides configuration options for OpenTelemetry tracing setup.
+// It supplements standard OpenTelemetry environment variables with additional
+// NTP Pool-specific configuration including TLS settings for secure OTLP export.
+type Config struct {
+	ServiceName         string               // Service name for resource identification (overrides OTEL_SERVICE_NAME)
+	Environment         string               // Deployment environment (development, staging, production)
+	Endpoint            string               // OTLP endpoint hostname/port (e.g., "otlp.example.com:4317")
+	EndpointURL         string               // Complete OTLP endpoint URL (e.g., "https://otlp.example.com:4317/v1/traces")
+	CertificateProvider GetClientCertificate // Client certificate provider for mutual TLS
+	RootCAs             *x509.CertPool       // CA certificate pool for server verification
+}
+
+// LogExporterFactory creates an OTLP log exporter using the provided configuration.
+// This allows the logger package to create exporters without importing the tracing package.
+type LogExporterFactory func(context.Context, *Config) (sdklog.Exporter, error)
+
+// MetricExporterFactory creates an OTLP metric exporter using the provided configuration.
+// This allows the metrics package to create exporters without importing the tracing package.
+type MetricExporterFactory func(context.Context, *Config) (sdkmetric.Exporter, error)
+
+// TraceExporterFactory creates an OTLP trace exporter using the provided configuration.
+// This allows for consistent trace exporter creation across packages.
+type TraceExporterFactory func(context.Context, *Config) (sdktrace.SpanExporter, error)
+
+// Global state for sharing configuration between packages
+var (
+	globalConfig          *Config
+	globalContext         context.Context
+	logExporterFactory    LogExporterFactory
+	metricExporterFactory MetricExporterFactory
+	traceExporterFactory  TraceExporterFactory
+	configMu              sync.RWMutex
+)
+
+// Store saves the tracer configuration and exporter factories for use by other packages.
+// This should be called by the tracing package during initialization.
+func Store(ctx context.Context, cfg *Config, logFactory LogExporterFactory, metricFactory MetricExporterFactory, traceFactory TraceExporterFactory) {
+	configMu.Lock()
+	defer configMu.Unlock()
+	globalConfig = cfg
+	globalContext = ctx
+	logExporterFactory = logFactory
+	metricExporterFactory = metricFactory
+	traceExporterFactory = traceFactory
+}
+
+// GetLogExporter returns the stored configuration and log exporter factory.
+// Returns nil values if no configuration has been stored yet.
+func GetLogExporter() (*Config, context.Context, LogExporterFactory) {
+	configMu.RLock()
+	defer configMu.RUnlock()
+	return globalConfig, globalContext, logExporterFactory
+}
+
+// GetMetricExporter returns the stored configuration and metric exporter factory.
+// Returns nil values if no configuration has been stored yet.
+func GetMetricExporter() (*Config, context.Context, MetricExporterFactory) {
+	configMu.RLock()
+	defer configMu.RUnlock()
+	return globalConfig, globalContext, metricExporterFactory
+}
+
+// GetTraceExporter returns the stored configuration and trace exporter factory.
+// Returns nil values if no configuration has been stored yet.
+func GetTraceExporter() (*Config, context.Context, TraceExporterFactory) {
+	configMu.RLock()
+	defer configMu.RUnlock()
+	return globalConfig, globalContext, traceExporterFactory
+}
+
+// Get returns the stored tracer configuration, context, and log exporter factory.
+// This maintains backward compatibility for the logger package.
+// Returns nil values if no configuration has been stored yet.
+func Get() (*Config, context.Context, LogExporterFactory) {
+	return GetLogExporter()
+}
+
+// IsConfigured returns true if tracer configuration has been stored.
+func IsConfigured() bool {
+	configMu.RLock()
+	defer configMu.RUnlock()
+	return globalConfig != nil && globalContext != nil
+}
+
+// Clear removes the stored configuration. This is primarily useful for testing.
+func Clear() {
+	configMu.Lock()
+	defer configMu.Unlock()
+	globalConfig = nil
+	globalContext = nil
+	logExporterFactory = nil
+	metricExporterFactory = nil
+	traceExporterFactory = nil
+}
+
+// getTLSConfig creates a TLS configuration from the provided Config.
+func getTLSConfig(cfg *Config) *tls.Config {
+	if cfg.CertificateProvider == nil {
+		return nil
+	}
+	return &tls.Config{
+		GetClientCertificate: cfg.CertificateProvider,
+		RootCAs:              cfg.RootCAs,
+	}
+}
+
+// getProtocol determines the OTLP protocol to use for the given signal type.
+// It follows OpenTelemetry environment variable precedence.
+func getProtocol(signalSpecificEnv string) string {
+	proto := os.Getenv(signalSpecificEnv)
+	if proto == "" {
+		proto = os.Getenv(otelExporterOTLPProtoEnvKey)
+	}
+	// Fallback to default, http/protobuf.
+	if proto == "" {
+		proto = "http/protobuf"
+	}
+	return proto
+}
+
+// CreateOTLPLogExporter creates an OTLP log exporter using the provided configuration.
+func CreateOTLPLogExporter(ctx context.Context, cfg *Config) (sdklog.Exporter, error) {
+	tlsConfig := getTLSConfig(cfg)
+	proto := getProtocol(otelExporterOTLPLogsProtoEnvKey)
+
+	switch proto {
+	case "grpc":
+		opts := []otlploggrpc.Option{
+			otlploggrpc.WithCompressor("gzip"),
+		}
+		if tlsConfig != nil {
+			opts = append(opts, otlploggrpc.WithTLSCredentials(credentials.NewTLS(tlsConfig)))
+		}
+		if len(cfg.Endpoint) > 0 {
+			opts = append(opts, otlploggrpc.WithEndpoint(cfg.Endpoint))
+		}
+		if len(cfg.EndpointURL) > 0 {
+			opts = append(opts, otlploggrpc.WithEndpointURL(cfg.EndpointURL))
+		}
+
+		return otlploggrpc.New(ctx, opts...)
+	case "http/protobuf", "http/json":
+		opts := []otlploghttp.Option{
+			otlploghttp.WithCompression(otlploghttp.GzipCompression),
+		}
+		if tlsConfig != nil {
+			opts = append(opts, otlploghttp.WithTLSClientConfig(tlsConfig))
+		}
+		if len(cfg.Endpoint) > 0 {
+			opts = append(opts, otlploghttp.WithEndpoint(cfg.Endpoint))
+		}
+		if len(cfg.EndpointURL) > 0 {
+			opts = append(opts, otlploghttp.WithEndpointURL(cfg.EndpointURL))
+		}
+
+		opts = append(opts, otlploghttp.WithRetry(otlploghttp.RetryConfig{
+			Enabled:         true,
+			InitialInterval: 3 * time.Second,
+			MaxInterval:     60 * time.Second,
+			MaxElapsedTime:  5 * time.Minute,
+		}))
+
+		return otlploghttp.New(ctx, opts...)
+	default:
+		return nil, newInvalidProtocolError(proto, "logs")
+	}
+}
+
+// CreateOTLPMetricExporter creates an OTLP metric exporter using the provided configuration.
+func CreateOTLPMetricExporter(ctx context.Context, cfg *Config) (sdkmetric.Exporter, error) {
+	tlsConfig := getTLSConfig(cfg)
+	proto := getProtocol(otelExporterOTLPMetricsProtoEnvKey)
+
+	switch proto {
+	case "grpc":
+		opts := []otlpmetricgrpc.Option{
+			otlpmetricgrpc.WithCompressor("gzip"),
+		}
+		if tlsConfig != nil {
+			opts = append(opts, otlpmetricgrpc.WithTLSCredentials(credentials.NewTLS(tlsConfig)))
+		}
+		if len(cfg.Endpoint) > 0 {
+			opts = append(opts, otlpmetricgrpc.WithEndpoint(cfg.Endpoint))
+		}
+		if len(cfg.EndpointURL) > 0 {
+			opts = append(opts, otlpmetricgrpc.WithEndpointURL(cfg.EndpointURL))
+		}
+
+		return otlpmetricgrpc.New(ctx, opts...)
+	case "http/protobuf", "http/json":
+		opts := []otlpmetrichttp.Option{
+			otlpmetrichttp.WithCompression(otlpmetrichttp.GzipCompression),
+		}
+		if tlsConfig != nil {
+			opts = append(opts, otlpmetrichttp.WithTLSClientConfig(tlsConfig))
+		}
+		if len(cfg.Endpoint) > 0 {
+			opts = append(opts, otlpmetrichttp.WithEndpoint(cfg.Endpoint))
+		}
+		if len(cfg.EndpointURL) > 0 {
+			opts = append(opts, otlpmetrichttp.WithEndpointURL(cfg.EndpointURL))
+		}
+
+		opts = append(opts, otlpmetrichttp.WithRetry(otlpmetrichttp.RetryConfig{
+			Enabled:         true,
+			InitialInterval: 3 * time.Second,
+			MaxInterval:     60 * time.Second,
+			MaxElapsedTime:  5 * time.Minute,
+		}))
+
+		return otlpmetrichttp.New(ctx, opts...)
+	default:
+		return nil, newInvalidProtocolError(proto, "metrics")
+	}
+}
+
+// CreateOTLPTraceExporter creates an OTLP trace exporter using the provided configuration.
+func CreateOTLPTraceExporter(ctx context.Context, cfg *Config) (sdktrace.SpanExporter, error) {
+	tlsConfig := getTLSConfig(cfg)
+	proto := getProtocol(otelExporterOTLPTracesProtoEnvKey)
+
+	var client otlptrace.Client
+
+	switch proto {
+	case "grpc":
+		opts := []otlptracegrpc.Option{
+			otlptracegrpc.WithCompressor("gzip"),
+		}
+		if tlsConfig != nil {
+			opts = append(opts, otlptracegrpc.WithTLSCredentials(credentials.NewTLS(tlsConfig)))
+		}
+		if len(cfg.Endpoint) > 0 {
+			opts = append(opts, otlptracegrpc.WithEndpoint(cfg.Endpoint))
+		}
+		if len(cfg.EndpointURL) > 0 {
+			opts = append(opts, otlptracegrpc.WithEndpointURL(cfg.EndpointURL))
+		}
+
+		client = otlptracegrpc.NewClient(opts...)
+	case "http/protobuf", "http/json":
+		opts := []otlptracehttp.Option{
+			otlptracehttp.WithCompression(otlptracehttp.GzipCompression),
+		}
+		if tlsConfig != nil {
+			opts = append(opts, otlptracehttp.WithTLSClientConfig(tlsConfig))
+		}
+		if len(cfg.Endpoint) > 0 {
+			opts = append(opts, otlptracehttp.WithEndpoint(cfg.Endpoint))
+		}
+		if len(cfg.EndpointURL) > 0 {
+			opts = append(opts, otlptracehttp.WithEndpointURL(cfg.EndpointURL))
+		}
+
+		opts = append(opts, otlptracehttp.WithRetry(otlptracehttp.RetryConfig{
+			Enabled:         true,
+			InitialInterval: 3 * time.Second,
+			MaxInterval:     60 * time.Second,
+			MaxElapsedTime:  5 * time.Minute,
+		}))
+
+		client = otlptracehttp.NewClient(opts...)
+	default:
+		return nil, newInvalidProtocolError(proto, "traces")
+	}
+
+	return otlptrace.New(ctx, client)
+}

internal/tracerconfig/config_test.go

@@ -0,0 +1,474 @@
+package tracerconfig
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"os"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	sdklog "go.opentelemetry.io/otel/sdk/log"
+	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+)
+
+func TestStore_And_Retrieve(t *testing.T) {
+	// Clear any existing configuration
+	Clear()
+
+	ctx := context.Background()
+	config := &Config{
+		ServiceName: "test-service",
+		Environment: "test",
+		Endpoint:    "localhost:4317",
+	}
+
+	// Create mock factories
+	logFactory := func(context.Context, *Config) (sdklog.Exporter, error) { return nil, nil }
+	metricFactory := func(context.Context, *Config) (sdkmetric.Exporter, error) { return nil, nil }
+	traceFactory := func(context.Context, *Config) (sdktrace.SpanExporter, error) { return nil, nil }
+
+	// Store configuration
+	Store(ctx, config, logFactory, metricFactory, traceFactory)
+
+	// Test IsConfigured
+	if !IsConfigured() {
+		t.Error("IsConfigured() should return true after Store()")
+	}
+
+	// Test GetLogExporter
+	cfg, ctx2, factory := GetLogExporter()
+	if cfg == nil || ctx2 == nil || factory == nil {
+		t.Error("GetLogExporter() should return non-nil values")
+	}
+	if cfg.ServiceName != "test-service" {
+		t.Errorf("Expected ServiceName 'test-service', got '%s'", cfg.ServiceName)
+	}
+
+	// Test GetMetricExporter
+	cfg, ctx3, metricFact := GetMetricExporter()
+	if cfg == nil || ctx3 == nil || metricFact == nil {
+		t.Error("GetMetricExporter() should return non-nil values")
+	}
+
+	// Test GetTraceExporter
+	cfg, ctx4, traceFact := GetTraceExporter()
+	if cfg == nil || ctx4 == nil || traceFact == nil {
+		t.Error("GetTraceExporter() should return non-nil values")
+	}
+
+	// Test backward compatibility Get()
+	cfg, ctx5, logFact := Get()
+	if cfg == nil || ctx5 == nil || logFact == nil {
+		t.Error("Get() should return non-nil values for backward compatibility")
+	}
+}
+
+func TestClear(t *testing.T) {
+	// Store some configuration first
+	ctx := context.Background()
+	config := &Config{ServiceName: "test"}
+	Store(ctx, config, nil, nil, nil)
+
+	if !IsConfigured() {
+		t.Error("Should be configured before Clear()")
+	}
+
+	// Clear configuration
+	Clear()
+
+	if IsConfigured() {
+		t.Error("Should not be configured after Clear()")
+	}
+
+	// All getters should return nil
+	cfg, ctx2, factory := GetLogExporter()
+	if cfg != nil || ctx2 != nil || factory != nil {
+		t.Error("GetLogExporter() should return nil values after Clear()")
+	}
+}
+
+func TestConcurrentAccess(t *testing.T) {
+	Clear()
+
+	ctx := context.Background()
+	config := &Config{ServiceName: "concurrent-test"}
+
+	var wg sync.WaitGroup
+	const numGoroutines = 10
+
+	// Test concurrent Store and Get operations
+	wg.Add(numGoroutines * 2)
+
+	// Concurrent Store operations
+	for i := 0; i < numGoroutines; i++ {
+		go func() {
+			defer wg.Done()
+			Store(ctx, config, nil, nil, nil)
+		}()
+	}
+
+	// Concurrent Get operations
+	for i := 0; i < numGoroutines; i++ {
+		go func() {
+			defer wg.Done()
+			IsConfigured()
+			GetLogExporter()
+			GetMetricExporter()
+			GetTraceExporter()
+		}()
+	}
+
+	wg.Wait()
+
+	// Should be configured after all operations
+	if !IsConfigured() {
+		t.Error("Should be configured after concurrent operations")
+	}
+}
+
+func TestGetTLSConfig(t *testing.T) {
+	tests := []struct {
+		name     string
+		config   *Config
+		expected bool // whether TLS config should be nil
+	}{
+		{
+			name:     "nil certificate provider",
+			config:   &Config{},
+			expected: true, // should be nil
+		},
+		{
+			name: "with certificate provider",
+			config: &Config{
+				CertificateProvider: func(*tls.CertificateRequestInfo) (*tls.Certificate, error) {
+					return &tls.Certificate{}, nil
+				},
+			},
+			expected: false, // should not be nil
+		},
+		{
+			name: "with certificate provider and RootCAs",
+			config: &Config{
+				CertificateProvider: func(*tls.CertificateRequestInfo) (*tls.Certificate, error) {
+					return &tls.Certificate{}, nil
+				},
+				RootCAs: x509.NewCertPool(),
+			},
+			expected: false, // should not be nil
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tlsConfig := getTLSConfig(tt.config)
+			if tt.expected && tlsConfig != nil {
+				t.Errorf("Expected nil TLS config, got %v", tlsConfig)
+			}
+			if !tt.expected && tlsConfig == nil {
+				t.Error("Expected non-nil TLS config, got nil")
+			}
+			if !tt.expected && tlsConfig != nil {
+				if tlsConfig.GetClientCertificate == nil {
+					t.Error("Expected GetClientCertificate to be set")
+				}
+				if tt.config.RootCAs != nil && tlsConfig.RootCAs != tt.config.RootCAs {
+					t.Error("Expected RootCAs to be set correctly")
+				}
+			}
+		})
+	}
+}
+
+func TestGetProtocol(t *testing.T) {
+	// Save original env vars
+	originalGeneral := os.Getenv(otelExporterOTLPProtoEnvKey)
+	originalLogs := os.Getenv(otelExporterOTLPLogsProtoEnvKey)
+
+	defer func() {
+		// Restore original env vars
+		if originalGeneral != "" {
+			os.Setenv(otelExporterOTLPProtoEnvKey, originalGeneral)
+		} else {
+			os.Unsetenv(otelExporterOTLPProtoEnvKey)
+		}
+		if originalLogs != "" {
+			os.Setenv(otelExporterOTLPLogsProtoEnvKey, originalLogs)
+		} else {
+			os.Unsetenv(otelExporterOTLPLogsProtoEnvKey)
+		}
+	}()
+
+	tests := []struct {
+		name           string
+		signalSpecific string
+		generalProto   string
+		specificProto  string
+		expectedResult string
+	}{
+		{
+			name:           "no env vars set - default",
+			signalSpecific: otelExporterOTLPLogsProtoEnvKey,
+			expectedResult: "http/protobuf",
+		},
+		{
+			name:           "general env var set",
+			signalSpecific: otelExporterOTLPLogsProtoEnvKey,
+			generalProto:   "grpc",
+			expectedResult: "grpc",
+		},
+		{
+			name:           "specific env var overrides general",
+			signalSpecific: otelExporterOTLPLogsProtoEnvKey,
+			generalProto:   "grpc",
+			specificProto:  "http/protobuf",
+			expectedResult: "http/protobuf",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Clear env vars
+			os.Unsetenv(otelExporterOTLPProtoEnvKey)
+			os.Unsetenv(otelExporterOTLPLogsProtoEnvKey)
+
+			// Set test env vars
+			if tt.generalProto != "" {
+				os.Setenv(otelExporterOTLPProtoEnvKey, tt.generalProto)
+			}
+			if tt.specificProto != "" {
+				os.Setenv(tt.signalSpecific, tt.specificProto)
+			}
+
+			result := getProtocol(tt.signalSpecific)
+			if result != tt.expectedResult {
+				t.Errorf("Expected protocol '%s', got '%s'", tt.expectedResult, result)
+			}
+		})
+	}
+}
+
+func TestCreateExporterErrors(t *testing.T) {
+	ctx := context.Background()
+	config := &Config{
+		ServiceName: "test-service",
+		Endpoint:    "invalid-endpoint",
+	}
+
+	// Test with invalid protocol for logs
+	os.Setenv(otelExporterOTLPLogsProtoEnvKey, "invalid-protocol")
+	defer os.Unsetenv(otelExporterOTLPLogsProtoEnvKey)
+
+	_, err := CreateOTLPLogExporter(ctx, config)
+	if err == nil {
+		t.Error("Expected error for invalid protocol")
+	}
+	// Check that it's a protocol error (the specific message will be different now)
+	if !strings.Contains(err.Error(), "invalid OTLP protocol") {
+		t.Errorf("Expected protocol error, got %v", err)
+	}
+
+	// Test with invalid protocol for metrics
+	os.Setenv(otelExporterOTLPMetricsProtoEnvKey, "invalid-protocol")
+	defer os.Unsetenv(otelExporterOTLPMetricsProtoEnvKey)
+
+	_, err = CreateOTLPMetricExporter(ctx, config)
+	if err == nil {
+		t.Error("Expected error for invalid protocol")
+	}
+	if !strings.Contains(err.Error(), "invalid OTLP protocol") {
+		t.Errorf("Expected protocol error, got %v", err)
+	}
+
+	// Test with invalid protocol for traces
+	os.Setenv(otelExporterOTLPTracesProtoEnvKey, "invalid-protocol")
+	defer os.Unsetenv(otelExporterOTLPTracesProtoEnvKey)
+
+	_, err = CreateOTLPTraceExporter(ctx, config)
+	if err == nil {
+		t.Error("Expected error for invalid protocol")
+	}
+	if !strings.Contains(err.Error(), "invalid OTLP protocol") {
+		t.Errorf("Expected protocol error, got %v", err)
+	}
+}
+
+func TestCreateExporterValidProtocols(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+	defer cancel()
+
+	config := &Config{
+		ServiceName: "test-service",
+		Endpoint:    "localhost:4317", // This will likely fail to connect, but should create exporter
+	}
+
+	protocols := []string{"grpc", "http/protobuf", "http/json"}
+
+	for _, proto := range protocols {
+		t.Run("logs_"+proto, func(t *testing.T) {
+			os.Setenv(otelExporterOTLPLogsProtoEnvKey, proto)
+			defer os.Unsetenv(otelExporterOTLPLogsProtoEnvKey)
+
+			exporter, err := CreateOTLPLogExporter(ctx, config)
+			if err != nil {
+				// Connection errors are expected since we're not running a real OTLP server
+				// but the exporter should be created successfully
+				t.Logf("Connection error expected: %v", err)
+			}
+			if exporter != nil {
+				exporter.Shutdown(ctx)
+			}
+		})
+
+		t.Run("metrics_"+proto, func(t *testing.T) {
+			os.Setenv(otelExporterOTLPMetricsProtoEnvKey, proto)
+			defer os.Unsetenv(otelExporterOTLPMetricsProtoEnvKey)
+
+			exporter, err := CreateOTLPMetricExporter(ctx, config)
+			if err != nil {
+				t.Logf("Connection error expected: %v", err)
+			}
+			if exporter != nil {
+				exporter.Shutdown(ctx)
+			}
+		})
+
+		t.Run("traces_"+proto, func(t *testing.T) {
+			os.Setenv(otelExporterOTLPTracesProtoEnvKey, proto)
+			defer os.Unsetenv(otelExporterOTLPTracesProtoEnvKey)
+
+			exporter, err := CreateOTLPTraceExporter(ctx, config)
+			if err != nil {
+				t.Logf("Connection error expected: %v", err)
+			}
+			if exporter != nil {
+				exporter.Shutdown(ctx)
+			}
+		})
+	}
+}
+
+func TestConfigValidation(t *testing.T) {
+	tests := []struct {
+		name      string
+		config    *Config
+		shouldErr bool
+	}{
+		{
+			name:      "valid empty config",
+			config:    &Config{},
+			shouldErr: false,
+		},
+		{
+			name: "valid config with endpoint",
+			config: &Config{
+				ServiceName: "test-service",
+				Endpoint:    "localhost:4317",
+			},
+			shouldErr: false,
+		},
+		{
+			name: "valid config with endpoint URL",
+			config: &Config{
+				ServiceName: "test-service",
+				EndpointURL: "https://otlp.example.com:4317/v1/traces",
+			},
+			shouldErr: false,
+		},
+		{
+			name: "invalid - both endpoint and endpoint URL",
+			config: &Config{
+				ServiceName: "test-service",
+				Endpoint:    "localhost:4317",
+				EndpointURL: "https://otlp.example.com:4317/v1/traces",
+			},
+			shouldErr: true,
+		},
+		{
+			name: "invalid - endpoint with protocol",
+			config: &Config{
+				ServiceName: "test-service",
+				Endpoint:    "https://localhost:4317",
+			},
+			shouldErr: true,
+		},
+		{
+			name: "invalid - empty endpoint",
+			config: &Config{
+				ServiceName: "test-service",
+				Endpoint:    "   ",
+			},
+			shouldErr: true,
+		},
+		{
+			name: "invalid - malformed endpoint URL",
+			config: &Config{
+				ServiceName: "test-service",
+				EndpointURL: "://invalid-url-missing-scheme",
+			},
+			shouldErr: true,
+		},
+		{
+			name: "invalid - empty service name",
+			config: &Config{
+				ServiceName: "   ",
+				Endpoint:    "localhost:4317",
+			},
+			shouldErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := tt.config.Validate()
+			if tt.shouldErr && err == nil {
+				t.Error("Expected validation error, got nil")
+			}
+			if !tt.shouldErr && err != nil {
+				t.Errorf("Expected no validation error, got: %v", err)
+			}
+		})
+	}
+}
+
+func TestValidateAndStore(t *testing.T) {
+	Clear()
+
+	ctx := context.Background()
+
+	// Test with valid config
+	validConfig := &Config{
+		ServiceName: "test-service",
+		Endpoint:    "localhost:4317",
+	}
+
+	err := ValidateAndStore(ctx, validConfig, nil, nil, nil)
+	if err != nil {
+		t.Errorf("ValidateAndStore with valid config should not error: %v", err)
+	}
+
+	if !IsConfigured() {
+		t.Error("Should be configured after ValidateAndStore")
+	}
+
+	Clear()
+
+	// Test with invalid config
+	invalidConfig := &Config{
+		ServiceName: "test-service",
+		Endpoint:    "localhost:4317",
+		EndpointURL: "https://example.com:4317", // both specified - invalid
+	}
+
+	err = ValidateAndStore(ctx, invalidConfig, nil, nil, nil)
+	if err == nil {
+		t.Error("ValidateAndStore with invalid config should return error")
+	}
+
+	if IsConfigured() {
+		t.Error("Should not be configured after failed ValidateAndStore")
+	}
+}

logger/buffering_exporter.go

@@ -0,0 +1,198 @@
+package logger
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+
+	"go.ntppool.org/common/internal/tracerconfig"
+	otellog "go.opentelemetry.io/otel/sdk/log"
+)
+
+// bufferingExporter wraps an OTLP exporter and buffers logs until tracing is configured
+type bufferingExporter struct {
+	mu sync.RWMutex
+
+	// Buffered records while waiting for tracing config
+	buffer      [][]otellog.Record
+	bufferSize  int
+	maxBuffSize int
+
+	// Real exporter (created when tracing is configured)
+	exporter otellog.Exporter
+
+	// Thread-safe initialization
+	initOnce sync.Once
+	initErr  error
+
+	// Background checker
+	stopChecker chan struct{}
+	checkerDone chan struct{}
+}
+
+// newBufferingExporter creates a new exporter that buffers logs until tracing is configured
+func newBufferingExporter() *bufferingExporter {
+	e := &bufferingExporter{
+		maxBuffSize: 1000, // Max number of batches to buffer
+		stopChecker: make(chan struct{}),
+		checkerDone: make(chan struct{}),
+	}
+
+	// Start background readiness checker
+	go e.checkReadiness()
+
+	return e
+}
+
+// Export implements otellog.Exporter
+func (e *bufferingExporter) Export(ctx context.Context, records []otellog.Record) error {
+	// Try initialization once
+	e.initOnce.Do(func() {
+		e.initErr = e.initialize()
+	})
+
+	// If initialization succeeded, use the exporter
+	if e.initErr == nil {
+		e.mu.RLock()
+		exporter := e.exporter
+		e.mu.RUnlock()
+
+		if exporter != nil {
+			return exporter.Export(ctx, records)
+		}
+	}
+
+	// Not ready yet, buffer the records
+	return e.bufferRecords(records)
+}
+
+// initialize attempts to create the real OTLP exporter using tracing config
+func (e *bufferingExporter) initialize() error {
+	cfg, ctx, factory := tracerconfig.Get()
+	if cfg == nil || ctx == nil || factory == nil {
+		return errors.New("tracer not configured yet")
+	}
+
+	// Add timeout for initialization
+	initCtx, cancel := context.WithTimeout(ctx, 10*time.Second)
+	defer cancel()
+
+	exporter, err := factory(initCtx, cfg)
+	if err != nil {
+		return fmt.Errorf("failed to create OTLP exporter: %w", err)
+	}
+
+	e.mu.Lock()
+	e.exporter = exporter
+	flushErr := e.flushBuffer(initCtx)
+	e.mu.Unlock()
+
+	if flushErr != nil {
+		// Log but don't fail initialization
+		Setup().Warn("buffer flush failed during initialization", "error", flushErr)
+	}
+
+	return nil
+}
+
+// bufferRecords adds records to the buffer for later processing
+func (e *bufferingExporter) bufferRecords(records []otellog.Record) error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	// Buffer the batch if we have space
+	if e.bufferSize < e.maxBuffSize {
+		// Clone records to avoid retention issues
+		cloned := make([]otellog.Record, len(records))
+		for i, r := range records {
+			cloned[i] = r.Clone()
+		}
+		e.buffer = append(e.buffer, cloned)
+		e.bufferSize++
+	}
+
+	// Always return success to BatchProcessor
+	return nil
+}
+
+// checkReadiness periodically checks if tracing is configured
+func (e *bufferingExporter) checkReadiness() {
+	defer close(e.checkerDone)
+
+	ticker := time.NewTicker(1 * time.Second) // Reduced frequency since OTLP handles retries
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			// If initialization failed, reset sync.Once to allow retry
+			// The OTLP exporter will handle its own retry logic
+			if e.initErr != nil {
+				e.initOnce = sync.Once{}
+			} else if e.exporter != nil {
+				return // Exporter ready, checker no longer needed
+			}
+
+		case <-e.stopChecker:
+			return
+		}
+	}
+}
+
+// flushBuffer sends all buffered batches through the real exporter
+func (e *bufferingExporter) flushBuffer(ctx context.Context) error {
+	if len(e.buffer) == 0 {
+		return nil
+	}
+
+	flushCtx, cancel := context.WithTimeout(ctx, 30*time.Second)
+	defer cancel()
+
+	var lastErr error
+	for _, batch := range e.buffer {
+		if err := e.exporter.Export(flushCtx, batch); err != nil {
+			lastErr = err
+		}
+	}
+
+	// Clear buffer after flush attempt
+	e.buffer = nil
+	e.bufferSize = 0
+
+	return lastErr
+}
+
+// ForceFlush implements otellog.Exporter
+func (e *bufferingExporter) ForceFlush(ctx context.Context) error {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+
+	if e.exporter != nil {
+		return e.exporter.ForceFlush(ctx)
+	}
+	return nil
+}
+
+// Shutdown implements otellog.Exporter
+func (e *bufferingExporter) Shutdown(ctx context.Context) error {
+	// Stop the readiness checker from continuing
+	close(e.stopChecker)
+
+	// Give one final chance for TLS/tracing to become ready before fully shutting down
+	e.initOnce.Do(func() {
+		e.initErr = e.initialize()
+	})
+
+	// Wait for readiness checker goroutine to complete
+	<-e.checkerDone
+
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	if e.exporter != nil {
+		return e.exporter.Shutdown(ctx)
+	}
+	return nil
+}

logger/logfmt.go

@@ -16,23 +16,28 @@ type logfmt struct {
 	mu   sync.Mutex
 }
 
+// createTextHandlerOptions creates the common slog.HandlerOptions used by all logfmt handlers
+func createTextHandlerOptions() *slog.HandlerOptions {
+	return &slog.HandlerOptions{
+		ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
+			if a.Key == slog.TimeKey && len(groups) == 0 {
+				return slog.Attr{}
+			}
+			if a.Key == slog.LevelKey && len(groups) == 0 {
+				return slog.Attr{}
+			}
+			return a
+		},
+	}
+}
+
 func newLogFmtHandler(next slog.Handler) slog.Handler {
 	buf := bytes.NewBuffer([]byte{})
 
 	h := &logfmt{
 		buf:  buf,
 		next: next,
-		txt: slog.NewTextHandler(buf, &slog.HandlerOptions{
-			ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
-				if a.Key == slog.TimeKey && len(groups) == 0 {
-					return slog.Attr{}
-				}
-				if a.Key == slog.LevelKey && len(groups) == 0 {
-					return slog.Attr{}
-				}
-				return a
-			},
-		}),
+		txt:  slog.NewTextHandler(buf, createTextHandlerOptions()),
 	}
 
 	return h
@@ -43,10 +48,11 @@ func (h *logfmt) Enabled(ctx context.Context, lvl slog.Level) bool {
 }
 
 func (h *logfmt) WithAttrs(attrs []slog.Attr) slog.Handler {
+	buf := bytes.NewBuffer([]byte{})
 	return &logfmt{
-		buf:  bytes.NewBuffer([]byte{}),
+		buf:  buf,
 		next: h.next.WithAttrs(slices.Clone(attrs)),
-		txt:  h.txt.WithAttrs(slices.Clone(attrs)),
+		txt:  slog.NewTextHandler(buf, createTextHandlerOptions()).WithAttrs(slices.Clone(attrs)),
 	}
 }
 
@@ -54,10 +60,11 @@ func (h *logfmt) WithGroup(g string) slog.Handler {
 	if g == "" {
 		return h
 	}
+	buf := bytes.NewBuffer([]byte{})
 	return &logfmt{
-		buf:  bytes.NewBuffer([]byte{}),
+		buf:  buf,
 		next: h.next.WithGroup(g),
-		txt:  h.txt.WithGroup(g),
+		txt:  slog.NewTextHandler(buf, createTextHandlerOptions()).WithGroup(g),
 	}
 }
 
@@ -69,10 +76,22 @@ func (h *logfmt) Handle(ctx context.Context, r slog.Record) error {
 		panic("buffer wasn't empty")
 	}
 
-	h.txt.Handle(ctx, r)
-	r.Message = h.buf.String()
-	r.Message = strings.TrimSuffix(r.Message, "\n")
+	// Format using text handler to get the formatted message
+	err := h.txt.Handle(ctx, r)
+	if err != nil {
+		return err
+	}
+
+	formattedMessage := h.buf.String()
+	formattedMessage = strings.TrimSuffix(formattedMessage, "\n")
 	h.buf.Reset()
 
-	return h.next.Handle(ctx, r)
+	// Create a new record with the formatted message
+	newRecord := slog.NewRecord(r.Time, r.Level, formattedMessage, r.PC)
+	r.Attrs(func(a slog.Attr) bool {
+		newRecord.AddAttrs(a)
+		return true
+	})
+
+	return h.next.Handle(ctx, newRecord)
 }

logger/logger.go

@@ -29,10 +29,13 @@ import (
 	"os"
 	"strconv"
 	"sync"
+	"time"
 
 	slogtraceid "github.com/remychantenay/slog-otel"
 	slogmulti "github.com/samber/slog-multi"
 	"go.opentelemetry.io/contrib/bridges/otelslog"
+	"go.opentelemetry.io/otel/log/global"
+	otellog "go.opentelemetry.io/otel/sdk/log"
 )
 
 // ConfigPrefix allows customizing the environment variable prefix for configuration.
@@ -85,9 +88,28 @@ func setupStdErrHandler() slog.Handler {
 
 func setupOtlpLogger() *slog.Logger {
 	setupOtlp.Do(func() {
-		otlpLogger = slog.New(
-			newLogFmtHandler(otelslog.NewHandler("common")),
+		// Create our buffering exporter
+		// It will buffer until tracing is configured
+		bufferingExp := newBufferingExporter()
+
+		// Use BatchProcessor with our custom exporter
+		processor := otellog.NewBatchProcessor(bufferingExp,
+			otellog.WithExportInterval(10*time.Second),
+			otellog.WithMaxQueueSize(2048),
+			otellog.WithExportMaxBatchSize(512),
 		)
+
+		// Create logger provider
+		provider := otellog.NewLoggerProvider(
+			otellog.WithProcessor(processor),
+		)
+
+		// Set global provider
+		global.SetLoggerProvider(provider)
+
+		// Create slog handler
+		handler := newLogFmtHandler(otelslog.NewHandler("common"))
+		otlpLogger = slog.New(handler)
 	})
 	return otlpLogger
 }

metrics/metrics.go

@@ -0,0 +1,122 @@
+// Package metrics provides OpenTelemetry-native metrics with OTLP export support.
+//
+// This package implements a metrics system using the OpenTelemetry metrics data model
+// with OTLP export capabilities. It's designed for new applications that want to use
+// structured metrics export to observability backends.
+//
+// Key features:
+//   - OpenTelemetry native metric types (Counter, Histogram, Gauge, etc.)
+//   - OTLP export for sending metrics to observability backends
+//   - Resource detection and correlation with traces/logs
+//   - Graceful handling when OTLP configuration is not available
+//
+// Example usage:
+//
+//	// Initialize metrics along with tracing
+//	shutdown, err := tracing.InitTracer(ctx, cfg)
+//	if err != nil {
+//		log.Fatal(err)
+//	}
+//	defer shutdown(ctx)
+//
+//	// Get a meter and create instruments
+//	meter := metrics.GetMeter("my-service")
+//	counter, _ := meter.Int64Counter("requests_total")
+//	counter.Add(ctx, 1, metric.WithAttributes(attribute.String("method", "GET")))
+package metrics
+
+import (
+	"context"
+	"log/slog"
+	"sync"
+	"time"
+
+	"go.ntppool.org/common/internal/tracerconfig"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/metric"
+	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
+)
+
+var (
+	meterProvider metric.MeterProvider
+	setupOnce     sync.Once
+	setupErr      error
+)
+
+// Setup initializes the OpenTelemetry metrics provider with OTLP export.
+// This function uses the configuration stored by the tracing package and
+// creates a metrics provider that exports to the same OTLP endpoint.
+//
+// The function is safe to call multiple times - it will only initialize once.
+// If tracing configuration is not available, it returns a no-op provider that
+// doesn't export metrics.
+//
+// Returns an error only if there's a configuration problem. Missing tracing
+// configuration is handled gracefully with a warning log.
+func Setup(ctx context.Context) error {
+	setupOnce.Do(func() {
+		setupErr = initializeMetrics(ctx)
+	})
+	return setupErr
+}
+
+// GetMeter returns a named meter for creating metric instruments.
+// The meter uses the configured metrics provider, or the global provider
+// if metrics haven't been set up yet.
+//
+// This is the primary entry point for creating metric instruments in your application.
+func GetMeter(name string, opts ...metric.MeterOption) metric.Meter {
+	if meterProvider == nil {
+		// Return the global provider as fallback (no-op if not configured)
+		return otel.GetMeterProvider().Meter(name, opts...)
+	}
+	return meterProvider.Meter(name, opts...)
+}
+
+// initializeMetrics sets up the OpenTelemetry metrics provider with OTLP export.
+func initializeMetrics(ctx context.Context) error {
+	log := slog.Default()
+
+	// Check if tracing configuration is available
+	cfg, configCtx, factory := tracerconfig.GetMetricExporter()
+	if cfg == nil || configCtx == nil || factory == nil {
+		log.Warn("metrics setup: tracing configuration not available, using no-op provider")
+		// Set the global provider as fallback - metrics just won't be exported
+		meterProvider = otel.GetMeterProvider()
+		return nil
+	}
+
+	// Create OTLP metrics exporter
+	exporter, err := factory(ctx, cfg)
+	if err != nil {
+		log.Error("metrics setup: failed to create OTLP exporter", "error", err)
+		// Fall back to global provider
+		meterProvider = otel.GetMeterProvider()
+		return nil
+	}
+
+	// Create metrics provider with the exporter
+	provider := sdkmetric.NewMeterProvider(
+		sdkmetric.WithReader(sdkmetric.NewPeriodicReader(
+			exporter,
+			sdkmetric.WithInterval(15*time.Second),
+		)),
+	)
+
+	// Set the global provider
+	otel.SetMeterProvider(provider)
+	meterProvider = provider
+
+	log.Info("metrics setup: OTLP metrics provider initialized")
+	return nil
+}
+
+// Shutdown gracefully shuts down the metrics provider.
+// This should be called during application shutdown to ensure all metrics
+// are properly flushed and exported.
+func Shutdown(ctx context.Context) error {
+	if provider, ok := meterProvider.(*sdkmetric.MeterProvider); ok {
+		return provider.Shutdown(ctx)
+	}
+	return nil
+}

metrics/metrics_test.go

@@ -0,0 +1,296 @@
+package metrics
+
+import (
+	"context"
+	"os"
+	"testing"
+	"time"
+
+	"go.ntppool.org/common/internal/tracerconfig"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/metric"
+	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
+	"go.opentelemetry.io/otel/sdk/metric/metricdata"
+)
+
+func TestSetup_NoConfiguration(t *testing.T) {
+	// Clear any existing configuration
+	tracerconfig.Clear()
+
+	ctx := context.Background()
+	err := Setup(ctx)
+	// Should not return an error even when no configuration is available
+	if err != nil {
+		t.Errorf("Setup() returned unexpected error: %v", err)
+	}
+
+	// Should be able to get a meter (even if it's a no-op)
+	meter := GetMeter("test-meter")
+	if meter == nil {
+		t.Error("GetMeter() returned nil")
+	}
+}
+
+func TestGetMeter(t *testing.T) {
+	// Clear any existing configuration
+	tracerconfig.Clear()
+
+	ctx := context.Background()
+	_ = Setup(ctx)
+
+	meter := GetMeter("test-service")
+	if meter == nil {
+		t.Fatal("GetMeter() returned nil")
+	}
+
+	// Test creating a counter instrument
+	counter, err := meter.Int64Counter("test_counter")
+	if err != nil {
+		t.Errorf("Failed to create counter: %v", err)
+	}
+
+	// Test using the counter (should not error even with no-op provider)
+	counter.Add(ctx, 1, metric.WithAttributes(attribute.String("test", "value")))
+}
+
+func TestSetup_MultipleCallsSafe(t *testing.T) {
+	// Clear any existing configuration
+	tracerconfig.Clear()
+
+	ctx := context.Background()
+
+	// Call Setup multiple times
+	err1 := Setup(ctx)
+	err2 := Setup(ctx)
+	err3 := Setup(ctx)
+
+	if err1 != nil {
+		t.Errorf("First Setup() call returned error: %v", err1)
+	}
+	if err2 != nil {
+		t.Errorf("Second Setup() call returned error: %v", err2)
+	}
+	if err3 != nil {
+		t.Errorf("Third Setup() call returned error: %v", err3)
+	}
+
+	// Should still be able to get meters
+	meter := GetMeter("test-meter")
+	if meter == nil {
+		t.Error("GetMeter() returned nil after multiple Setup() calls")
+	}
+}
+
+func TestSetup_WithConfiguration(t *testing.T) {
+	// Clear any existing configuration
+	tracerconfig.Clear()
+
+	ctx := context.Background()
+	config := &tracerconfig.Config{
+		ServiceName: "test-metrics-service",
+		Environment: "test",
+		Endpoint:    "localhost:4317", // Will likely fail to connect, but should set up provider
+	}
+
+	// Create a mock exporter factory that returns a working exporter
+	mockFactory := func(ctx context.Context, cfg *tracerconfig.Config) (sdkmetric.Exporter, error) {
+		// Create a simple in-memory exporter for testing
+		return &mockMetricExporter{}, nil
+	}
+
+	// Store configuration with mock factory
+	tracerconfig.Store(ctx, config, nil, mockFactory, nil)
+
+	// Setup metrics
+	err := Setup(ctx)
+	if err != nil {
+		t.Errorf("Setup() returned error: %v", err)
+	}
+
+	// Should be able to get a meter
+	meter := GetMeter("test-service")
+	if meter == nil {
+		t.Fatal("GetMeter() returned nil")
+	}
+
+	// Test creating and using instruments
+	counter, err := meter.Int64Counter("test_counter")
+	if err != nil {
+		t.Errorf("Failed to create counter: %v", err)
+	}
+
+	histogram, err := meter.Float64Histogram("test_histogram")
+	if err != nil {
+		t.Errorf("Failed to create histogram: %v", err)
+	}
+
+	gauge, err := meter.Int64UpDownCounter("test_gauge")
+	if err != nil {
+		t.Errorf("Failed to create gauge: %v", err)
+	}
+
+	// Use the instruments
+	counter.Add(ctx, 1, metric.WithAttributes(attribute.String("test", "value")))
+	histogram.Record(ctx, 1.5, metric.WithAttributes(attribute.String("test", "value")))
+	gauge.Add(ctx, 10, metric.WithAttributes(attribute.String("test", "value")))
+
+	// Test shutdown
+	err = Shutdown(ctx)
+	if err != nil {
+		t.Errorf("Shutdown() returned error: %v", err)
+	}
+}
+
+func TestSetup_WithRealOTLPConfig(t *testing.T) {
+	// Skip this test in short mode since it may try to make network connections
+	if testing.Short() {
+		t.Skip("Skipping integration test in short mode")
+	}
+
+	// Clear any existing configuration
+	tracerconfig.Clear()
+
+	// Set environment variables for OTLP configuration
+	originalEndpoint := os.Getenv("OTEL_EXPORTER_OTLP_ENDPOINT")
+	originalProtocol := os.Getenv("OTEL_EXPORTER_OTLP_PROTOCOL")
+
+	defer func() {
+		if originalEndpoint != "" {
+			os.Setenv("OTEL_EXPORTER_OTLP_ENDPOINT", originalEndpoint)
+		} else {
+			os.Unsetenv("OTEL_EXPORTER_OTLP_ENDPOINT")
+		}
+		if originalProtocol != "" {
+			os.Setenv("OTEL_EXPORTER_OTLP_PROTOCOL", originalProtocol)
+		} else {
+			os.Unsetenv("OTEL_EXPORTER_OTLP_PROTOCOL")
+		}
+	}()
+
+	os.Setenv("OTEL_EXPORTER_OTLP_ENDPOINT", "http://localhost:4318") // HTTP endpoint
+	os.Setenv("OTEL_EXPORTER_OTLP_PROTOCOL", "http/protobuf")
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	config := &tracerconfig.Config{
+		ServiceName: "test-metrics-e2e",
+		Environment: "test",
+		Endpoint:    "localhost:4318",
+	}
+
+	// Store configuration with real factory
+	tracerconfig.Store(ctx, config, nil, tracerconfig.CreateOTLPMetricExporter, nil)
+
+	// Setup metrics - this may fail if no OTLP collector is running, which is okay
+	err := Setup(ctx)
+	if err != nil {
+		t.Logf("Setup() returned error (expected if no OTLP collector): %v", err)
+	}
+
+	// Should still be able to get a meter
+	meter := GetMeter("test-service-e2e")
+	if meter == nil {
+		t.Fatal("GetMeter() returned nil")
+	}
+
+	// Create and use instruments
+	counter, err := meter.Int64Counter("e2e_test_counter")
+	if err != nil {
+		t.Errorf("Failed to create counter: %v", err)
+	}
+
+	// Add some metrics
+	for i := 0; i < 5; i++ {
+		counter.Add(ctx, 1, metric.WithAttributes(
+			attribute.String("iteration", string(rune('0'+i))),
+			attribute.String("test_type", "e2e"),
+		))
+	}
+
+	// Give some time for export (if collector is running)
+	time.Sleep(100 * time.Millisecond)
+
+	// Test shutdown
+	err = Shutdown(ctx)
+	if err != nil {
+		t.Logf("Shutdown() returned error (may be expected): %v", err)
+	}
+}
+
+func TestConcurrentMetricUsage(t *testing.T) {
+	// Clear any existing configuration
+	tracerconfig.Clear()
+
+	ctx := context.Background()
+	config := &tracerconfig.Config{
+		ServiceName: "concurrent-test",
+	}
+
+	// Use mock factory
+	mockFactory := func(ctx context.Context, cfg *tracerconfig.Config) (sdkmetric.Exporter, error) {
+		return &mockMetricExporter{}, nil
+	}
+
+	tracerconfig.Store(ctx, config, nil, mockFactory, nil)
+	Setup(ctx)
+
+	meter := GetMeter("concurrent-test")
+	counter, err := meter.Int64Counter("concurrent_counter")
+	if err != nil {
+		t.Fatalf("Failed to create counter: %v", err)
+	}
+
+	// Test concurrent metric usage
+	const numGoroutines = 10
+	const metricsPerGoroutine = 100
+
+	done := make(chan bool, numGoroutines)
+
+	for i := 0; i < numGoroutines; i++ {
+		go func(goroutineID int) {
+			for j := 0; j < metricsPerGoroutine; j++ {
+				counter.Add(ctx, 1, metric.WithAttributes(
+					attribute.Int("goroutine", goroutineID),
+					attribute.Int("iteration", j),
+				))
+			}
+			done <- true
+		}(i)
+	}
+
+	// Wait for all goroutines to complete
+	for i := 0; i < numGoroutines; i++ {
+		<-done
+	}
+
+	// Shutdown
+	err = Shutdown(ctx)
+	if err != nil {
+		t.Errorf("Shutdown() returned error: %v", err)
+	}
+}
+
+// mockMetricExporter is a simple mock exporter for testing
+type mockMetricExporter struct{}
+
+func (m *mockMetricExporter) Export(ctx context.Context, rm *metricdata.ResourceMetrics) error {
+	// Just pretend to export
+	return nil
+}
+
+func (m *mockMetricExporter) ForceFlush(ctx context.Context) error {
+	return nil
+}
+
+func (m *mockMetricExporter) Shutdown(ctx context.Context) error {
+	return nil
+}
+
+func (m *mockMetricExporter) Temporality(kind sdkmetric.InstrumentKind) metricdata.Temporality {
+	return metricdata.CumulativeTemporality
+}
+
+func (m *mockMetricExporter) Aggregation(kind sdkmetric.InstrumentKind) sdkmetric.Aggregation {
+	return sdkmetric.DefaultAggregationSelector(kind)
+}

tracing/tracing.go

@@ -38,26 +38,23 @@ package tracing
 
 import (
 	"context"
-	"crypto/tls"
 	"crypto/x509"
 	"errors"
+	"log/slog"
 	"os"
 	"slices"
 	"time"
 
-	"go.ntppool.org/common/logger"
+	"go.ntppool.org/common/internal/tracerconfig"
 	"go.ntppool.org/common/version"
-	"google.golang.org/grpc/credentials"
 
 	"go.opentelemetry.io/contrib/exporters/autoexport"
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/exporters/otlp/otlptrace"
-	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
-	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
-	logglobal "go.opentelemetry.io/otel/log/global"
+	"go.opentelemetry.io/otel/log/global"
 	"go.opentelemetry.io/otel/propagation"
 	sdklog "go.opentelemetry.io/otel/sdk/log"
+	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
 	"go.opentelemetry.io/otel/sdk/resource"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
 	semconv "go.opentelemetry.io/otel/semconv/v1.26.0"
@@ -67,12 +64,25 @@ import (
 const (
 	// svcNameKey is the environment variable name that Service Name information will be read from.
 	svcNameKey = "OTEL_SERVICE_NAME"
-
-	otelExporterOTLPProtoEnvKey       = "OTEL_EXPORTER_OTLP_PROTOCOL"
-	otelExporterOTLPTracesProtoEnvKey = "OTEL_EXPORTER_OTLP_TRACES_PROTOCOL"
 )
 
-var errInvalidOTLPProtocol = errors.New("invalid OTLP protocol - should be one of ['grpc', 'http/protobuf']")
+// createOTLPLogExporter creates an OTLP log exporter using the provided configuration.
+// This function is used as the LogExporterFactory for the tracerconfig bridge.
+func createOTLPLogExporter(ctx context.Context, cfg *tracerconfig.Config) (sdklog.Exporter, error) {
+	return tracerconfig.CreateOTLPLogExporter(ctx, cfg)
+}
+
+// createOTLPMetricExporter creates an OTLP metric exporter using the provided configuration.
+// This function is used as the MetricExporterFactory for the tracerconfig bridge.
+func createOTLPMetricExporter(ctx context.Context, cfg *tracerconfig.Config) (sdkmetric.Exporter, error) {
+	return tracerconfig.CreateOTLPMetricExporter(ctx, cfg)
+}
+
+// createOTLPTraceExporter creates an OTLP trace exporter using the provided configuration.
+// This function is used as the TraceExporterFactory for the tracerconfig bridge.
+func createOTLPTraceExporter(ctx context.Context, cfg *tracerconfig.Config) (sdktrace.SpanExporter, error) {
+	return tracerconfig.CreateOTLPTraceExporter(ctx, cfg)
+}
 
 // https://github.com/open-telemetry/opentelemetry-go/blob/main/exporters/otlp/otlptrace/otlptracehttp/example_test.go
 
@@ -98,10 +108,9 @@ func Start(ctx context.Context, spanName string, opts ...trace.SpanStartOption)
 	return Tracer().Start(ctx, spanName, opts...)
 }
 
-// GetClientCertificate defines a function type for providing client certificates for mutual TLS.
-// This is used when exporting telemetry data to secured OTLP endpoints that require
-// client certificate authentication.
-type GetClientCertificate func(*tls.CertificateRequestInfo) (*tls.Certificate, error)
+// GetClientCertificate is an alias for the type defined in tracerconfig.
+// This maintains backward compatibility for existing code.
+type GetClientCertificate = tracerconfig.GetClientCertificate
 
 // TracerConfig provides configuration options for OpenTelemetry tracing setup.
 // It supplements standard OpenTelemetry environment variables with additional
@@ -143,7 +152,18 @@ func SetupSDK(ctx context.Context, cfg *TracerConfig) (shutdown TpShutdownFunc,
 		cfg = &TracerConfig{}
 	}
 
-	log := logger.Setup()
+	// Store configuration for use by logger and metrics packages via bridge
+	bridgeConfig := &tracerconfig.Config{
+		ServiceName:         cfg.ServiceName,
+		Environment:         cfg.Environment,
+		Endpoint:            cfg.Endpoint,
+		EndpointURL:         cfg.EndpointURL,
+		CertificateProvider: cfg.CertificateProvider,
+		RootCAs:             cfg.RootCAs,
+	}
+	tracerconfig.Store(ctx, bridgeConfig, createOTLPLogExporter, createOTLPMetricExporter, createOTLPTraceExporter)
+
+	log := slog.Default()
 
 	if serviceName := os.Getenv(svcNameKey); len(serviceName) == 0 {
 		if len(cfg.ServiceName) > 0 {
@@ -184,13 +204,21 @@ func SetupSDK(ctx context.Context, cfg *TracerConfig) (shutdown TpShutdownFunc,
 
 	var shutdownFuncs []func(context.Context) error
 	shutdown = func(ctx context.Context) error {
+		// Force flush the global logger provider before shutting down anything else
+		if loggerProvider := global.GetLoggerProvider(); loggerProvider != nil {
+			if sdkProvider, ok := loggerProvider.(*sdklog.LoggerProvider); ok {
+				if flushErr := sdkProvider.ForceFlush(ctx); flushErr != nil {
+					log.Warn("logger provider force flush failed", "err", flushErr)
+				}
+			}
+		}
+
 		var err error
 		// need to shutdown the providers first,
 		// exporters after which is the opposite
 		// order they are setup.
 		slices.Reverse(shutdownFuncs)
 		for _, fn := range shutdownFuncs {
-			// log.Warn("shutting down", "fn", fn)
 			err = errors.Join(err, fn(ctx))
 		}
 		shutdownFuncs = nil
@@ -212,9 +240,9 @@ func SetupSDK(ctx context.Context, cfg *TracerConfig) (shutdown TpShutdownFunc,
 
 	switch os.Getenv("OTEL_TRACES_EXPORTER") {
 	case "":
-		spanExporter, err = newOLTPExporter(ctx, cfg)
+		spanExporter, err = createOTLPTraceExporter(ctx, bridgeConfig)
 	case "otlp":
-		spanExporter, err = newOLTPExporter(ctx, cfg)
+		spanExporter, err = createOTLPTraceExporter(ctx, bridgeConfig)
 	default:
 		// log.Debug("OTEL_TRACES_EXPORTER", "fallback", os.Getenv("OTEL_TRACES_EXPORTER"))
 		spanExporter, err = autoexport.NewSpanExporter(ctx)
@@ -225,13 +253,6 @@ func SetupSDK(ctx context.Context, cfg *TracerConfig) (shutdown TpShutdownFunc,
 	}
 	shutdownFuncs = append(shutdownFuncs, spanExporter.Shutdown)
 
-	logExporter, err := autoexport.NewLogExporter(ctx)
-	if err != nil {
-		handleErr(err)
-		return
-	}
-	shutdownFuncs = append(shutdownFuncs, logExporter.Shutdown)
-
 	// Set up trace provider.
 	tracerProvider, err := newTraceProvider(spanExporter, res)
 	if err != nil {
@@ -241,19 +262,6 @@ func SetupSDK(ctx context.Context, cfg *TracerConfig) (shutdown TpShutdownFunc,
 	shutdownFuncs = append(shutdownFuncs, tracerProvider.Shutdown)
 	otel.SetTracerProvider(tracerProvider)
 
-	logProvider := sdklog.NewLoggerProvider(sdklog.WithResource(res),
-		sdklog.WithProcessor(
-			sdklog.NewBatchProcessor(logExporter, sdklog.WithExportBufferSize(10)),
-		),
-	)
-
-	logglobal.SetLoggerProvider(logProvider)
-	shutdownFuncs = append(shutdownFuncs, func(ctx context.Context) error {
-		logProvider.ForceFlush(ctx)
-		return logProvider.Shutdown(ctx)
-	},
-	)
-
 	if err != nil {
 		handleErr(err)
 		return
@@ -262,74 +270,6 @@ func SetupSDK(ctx context.Context, cfg *TracerConfig) (shutdown TpShutdownFunc,
 	return
 }
 
-func newOLTPExporter(ctx context.Context, cfg *TracerConfig) (sdktrace.SpanExporter, error) {
-	log := logger.Setup()
-
-	var tlsConfig *tls.Config
-
-	if cfg.CertificateProvider != nil {
-		tlsConfig = &tls.Config{
-			GetClientCertificate: cfg.CertificateProvider,
-			RootCAs:              cfg.RootCAs,
-		}
-	}
-
-	proto := os.Getenv(otelExporterOTLPTracesProtoEnvKey)
-	if proto == "" {
-		proto = os.Getenv(otelExporterOTLPProtoEnvKey)
-	}
-
-	// Fallback to default, http/protobuf.
-	if proto == "" {
-		proto = "http/protobuf"
-	}
-
-	var client otlptrace.Client
-
-	switch proto {
-	case "grpc":
-		opts := []otlptracegrpc.Option{
-			otlptracegrpc.WithCompressor("gzip"),
-		}
-		if tlsConfig != nil {
-			opts = append(opts, otlptracegrpc.WithTLSCredentials(credentials.NewTLS(tlsConfig)))
-		}
-		if len(cfg.Endpoint) > 0 {
-			log.Info("adding option", "Endpoint", cfg.Endpoint)
-			opts = append(opts, otlptracegrpc.WithEndpoint(cfg.Endpoint))
-		}
-		if len(cfg.EndpointURL) > 0 {
-			log.Info("adding option", "EndpointURL", cfg.EndpointURL)
-			opts = append(opts, otlptracegrpc.WithEndpointURL(cfg.EndpointURL))
-		}
-
-		client = otlptracegrpc.NewClient(opts...)
-	case "http/protobuf", "http/json":
-		opts := []otlptracehttp.Option{
-			otlptracehttp.WithCompression(otlptracehttp.GzipCompression),
-		}
-		if tlsConfig != nil {
-			opts = append(opts, otlptracehttp.WithTLSClientConfig(tlsConfig))
-		}
-		if len(cfg.Endpoint) > 0 {
-			opts = append(opts, otlptracehttp.WithEndpoint(cfg.Endpoint))
-		}
-		if len(cfg.EndpointURL) > 0 {
-			opts = append(opts, otlptracehttp.WithEndpointURL(cfg.EndpointURL))
-		}
-
-		client = otlptracehttp.NewClient(opts...)
-	default:
-		return nil, errInvalidOTLPProtocol
-	}
-
-	exporter, err := otlptrace.New(ctx, client)
-	if err != nil {
-		log.ErrorContext(ctx, "creating OTLP trace exporter", "err", err)
-	}
-	return exporter, err
-}
-
 func newTraceProvider(traceExporter sdktrace.SpanExporter, res *resource.Resource) (*sdktrace.TracerProvider, error) {
 	traceProvider := sdktrace.NewTracerProvider(
 		sdktrace.WithResource(res),

version/version.go

@@ -10,8 +10,18 @@
 //	  -X go.ntppool.org/common/version.buildTime=2023-01-01T00:00:00Z \
 //	  -X go.ntppool.org/common/version.gitVersion=abc123"
 //
-// The package also automatically extracts build information from Go's debug.BuildInfo
-// when available, providing fallback values for VCS time and revision.
+// Build time supports both Unix epoch timestamps and RFC3339 format:
+//
+//	# Unix epoch (simpler, recommended)
+//	go build -ldflags "-X go.ntppool.org/common/version.buildTime=$(date +%s)"
+//
+//	# RFC3339 format
+//	go build -ldflags "-X go.ntppool.org/common/version.buildTime=$(date -u +%Y-%m-%dT%H:%M:%SZ)"
+//
+// Both formats are automatically converted to RFC3339 for consistent output. The buildTime
+// parameter takes priority over Git commit time. If buildTime is not specified, the package
+// automatically extracts build information from Go's debug.BuildInfo when available,
+// providing fallback values for VCS time and revision.
 package version
 
 import (
@@ -19,7 +29,9 @@ import (
 	"log/slog"
 	"runtime"
 	"runtime/debug"
+	"strconv"
 	"strings"
+	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/spf13/cobra"
@@ -30,7 +42,7 @@ import (
 // If not set, defaults to "dev-snapshot". The version should follow semantic versioning.
 var (
 	VERSION     string // Semantic version (e.g., "1.0.0" or "v1.0.0")
-	buildTime   string // Build timestamp (RFC3339 format)
+	buildTime   string // Build timestamp (Unix epoch or RFC3339, normalized to RFC3339)
 	gitVersion  string // Git commit hash
 	gitModified bool   // Whether the working tree was modified during build
 )
@@ -38,6 +50,28 @@ var (
 // info holds the consolidated version information extracted from build variables and debug.BuildInfo.
 var info Info
 
+// parseBuildTime converts a build time string to RFC3339 format.
+// Supports both Unix epoch timestamps (numeric strings) and RFC3339 format.
+// Returns the input unchanged if it cannot be parsed as either format.
+func parseBuildTime(s string) string {
+	if s == "" {
+		return s
+	}
+
+	// Try parsing as Unix epoch timestamp (numeric string)
+	if epoch, err := strconv.ParseInt(s, 10, 64); err == nil {
+		return time.Unix(epoch, 0).UTC().Format(time.RFC3339)
+	}
+
+	// Try parsing as RFC3339 to validate format
+	if _, err := time.Parse(time.RFC3339, s); err == nil {
+		return s // Already in RFC3339 format
+	}
+
+	// Return original string if neither format works (graceful fallback)
+	return s
+}
+
 // Info represents structured version and build information.
 // This struct is used for JSON serialization and programmatic access to build metadata.
 type Info struct {
@@ -48,6 +82,7 @@ type Info struct {
 }
 
 func init() {
+	buildTime = parseBuildTime(buildTime)
 	info.BuildTime = buildTime
 	info.GitRev = gitVersion
 
@@ -67,9 +102,9 @@ func init() {
 			switch h.Key {
 			case "vcs.time":
 				if len(buildTime) == 0 {
-					buildTime = h.Value
+					buildTime = parseBuildTime(h.Value)
+					info.BuildTime = buildTime
 				}
-				info.BuildTime = h.Value
 			case "vcs.revision":
 				// https://blog.carlmjohnson.net/post/2023/golang-git-hash-how-to/
 				// todo: use BuildInfo.Main.Version if revision is empty

version/version_test.go

@@ -309,3 +309,106 @@ func BenchmarkCheckVersionDevSnapshot(b *testing.B) {
 		_ = CheckVersion(version, minimum)
 	}
 }
+
+func TestParseBuildTime(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "Unix epoch timestamp",
+			input:    "1672531200", // 2023-01-01T00:00:00Z
+			expected: "2023-01-01T00:00:00Z",
+		},
+		{
+			name:     "Unix epoch zero",
+			input:    "0",
+			expected: "1970-01-01T00:00:00Z",
+		},
+		{
+			name:     "Valid RFC3339 format",
+			input:    "2023-12-25T15:30:45Z",
+			expected: "2023-12-25T15:30:45Z",
+		},
+		{
+			name:     "RFC3339 with timezone",
+			input:    "2023-12-25T10:30:45-05:00",
+			expected: "2023-12-25T10:30:45-05:00",
+		},
+		{
+			name:     "Empty string",
+			input:    "",
+			expected: "",
+		},
+		{
+			name:     "Invalid format - return unchanged",
+			input:    "not-a-date",
+			expected: "not-a-date",
+		},
+		{
+			name:     "Invalid timestamp - return unchanged",
+			input:    "invalid-timestamp",
+			expected: "invalid-timestamp",
+		},
+		{
+			name:     "Partial date - return unchanged",
+			input:    "2023-01-01",
+			expected: "2023-01-01",
+		},
+		{
+			name:     "Negative epoch - should work",
+			input:    "-1",
+			expected: "1969-12-31T23:59:59Z",
+		},
+		{
+			name:     "Large epoch timestamp",
+			input:    "4102444800", // 2100-01-01T00:00:00Z
+			expected: "2100-01-01T00:00:00Z",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := parseBuildTime(tt.input)
+			if result != tt.expected {
+				t.Errorf("parseBuildTime(%q) = %q, expected %q", tt.input, result, tt.expected)
+			}
+		})
+	}
+}
+
+func TestParseBuildTimeConsistency(t *testing.T) {
+	// Test that calling parseBuildTime multiple times with the same input returns the same result
+	testInputs := []string{
+		"1672531200",
+		"2023-01-01T00:00:00Z",
+		"invalid-date",
+		"",
+	}
+
+	for _, input := range testInputs {
+		result1 := parseBuildTime(input)
+		result2 := parseBuildTime(input)
+		if result1 != result2 {
+			t.Errorf("parseBuildTime(%q) not consistent: %q != %q", input, result1, result2)
+		}
+	}
+}
+
+func BenchmarkParseBuildTime(b *testing.B) {
+	inputs := []string{
+		"1672531200",                 // Unix epoch
+		"2023-01-01T00:00:00Z",      // RFC3339
+		"invalid-timestamp",          // Invalid
+		"",                          // Empty
+	}
+
+	for _, input := range inputs {
+		b.Run(input, func(b *testing.B) {
+			for i := 0; i < b.N; i++ {
+				_ = parseBuildTime(input)
+			}
+		})
+	}
+}