feat(database): add DATABASE_CONFIG_FILE env override

Allow overriding default database.yaml paths via DATABASE_CONFIG_FILE
environment variable. When set, uses single specified file instead of
default ["database.yaml", "/vault/secrets/database.yaml"] search paths.

Maintains backward compatibility when env var not set.

database/config.go

@@ -1,6 +1,7 @@
 package database
 
 import (
+	"os"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -36,10 +37,20 @@ type ConfigOptions struct {
 	ConnMaxLifetime time.Duration
 }
 
+// getConfigFiles returns the list of config files to search for database configuration.
+// If DATABASE_CONFIG_FILE environment variable is set, it returns that single file.
+// Otherwise, it returns the default paths.
+func getConfigFiles() []string {
+	if configFile := os.Getenv("DATABASE_CONFIG_FILE"); configFile != "" {
+		return []string{configFile}
+	}
+	return []string{"database.yaml", "/vault/secrets/database.yaml"}
+}
+
 // DefaultConfigOptions returns the standard configuration options used by API package
 func DefaultConfigOptions() ConfigOptions {
 	return ConfigOptions{
-		ConfigFiles:          []string{"database.yaml", "/vault/secrets/database.yaml"},
+		ConfigFiles:          getConfigFiles(),
 		EnablePoolMonitoring: true,
 		PrometheusRegisterer: prometheus.DefaultRegisterer,
 		MaxOpenConns:         25,
@@ -51,7 +62,7 @@ func DefaultConfigOptions() ConfigOptions {
 // MonitorConfigOptions returns configuration options optimized for Monitor package
 func MonitorConfigOptions() ConfigOptions {
 	return ConfigOptions{
-		ConfigFiles:          []string{"database.yaml", "/vault/secrets/database.yaml"},
+		ConfigFiles:          getConfigFiles(),
 		EnablePoolMonitoring: false, // Monitor doesn't need metrics
 		PrometheusRegisterer: nil,   // No Prometheus dependency
 		MaxOpenConns:         10,

logger/buffering_exporter.go

@@ -23,9 +23,8 @@ type bufferingExporter struct {
 	// Real exporter (created when tracing is configured)
 	exporter otellog.Exporter
 
-	// Thread-safe initialization
-	initOnce sync.Once
-	initErr  error
+	// Thread-safe initialization state (managed only by checkReadiness)
+	initErr error
 
 	// Background checker
 	stopChecker chan struct{}
@@ -48,20 +47,13 @@ func newBufferingExporter() *bufferingExporter {
 
 // 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()
-	})
+	// Check if exporter is ready (initialization handled by checkReadiness goroutine)
+	e.mu.RLock()
+	exporter := e.exporter
+	e.mu.RUnlock()
 
-	// 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)
-		}
+	if exporter != nil {
+		return exporter.Export(ctx, records)
 	}
 
 	// Not ready yet, buffer the records
@@ -117,24 +109,31 @@ func (e *bufferingExporter) bufferRecords(records []otellog.Record) error {
 	return nil
 }
 
-// checkReadiness periodically checks if tracing is configured
+// checkReadiness periodically attempts initialization until successful
 func (e *bufferingExporter) checkReadiness() {
 	defer close(e.checkerDone)
 
-	ticker := time.NewTicker(1 * time.Second) // Reduced frequency since OTLP handles retries
+	ticker := time.NewTicker(1 * time.Second)
 	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 {
+			// Check if we already have a working exporter
+			e.mu.RLock()
+			hasExporter := e.exporter != nil
+			e.mu.RUnlock()
+
+			if hasExporter {
 				return // Exporter ready, checker no longer needed
 			}
 
+			// Try to initialize
+			err := e.initialize()
+			e.mu.Lock()
+			e.initErr = err
+			e.mu.Unlock()
+
 		case <-e.stopChecker:
 			return
 		}
@@ -180,14 +179,21 @@ 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
 
+	// Give one final chance for TLS/tracing to become ready for buffer flushing
+	e.mu.RLock()
+	hasExporter := e.exporter != nil
+	e.mu.RUnlock()
+
+	if !hasExporter {
+		err := e.initialize()
+		e.mu.Lock()
+		e.initErr = err
+		e.mu.Unlock()
+	}
+
 	e.mu.Lock()
 	defer e.mu.Unlock()