feat(log): wire log db, metrics, and body toggle

internal/service/log_indexes.go

@@ -0,0 +1,28 @@
+package service
+
+import (
+	"fmt"
+
+	"gorm.io/gorm"
+)
+
+// EnsureLogIndexes creates log_records indexes if missing.
+func EnsureLogIndexes(db *gorm.DB) error {
+	if db == nil {
+		return nil
+	}
+	stmts := []string{
+		`CREATE INDEX IF NOT EXISTS idx_log_records_created_at ON log_records(created_at);`,
+		`CREATE INDEX IF NOT EXISTS idx_log_records_key_id ON log_records(key_id);`,
+		`CREATE INDEX IF NOT EXISTS idx_log_records_model_name ON log_records(model_name);`,
+		`CREATE INDEX IF NOT EXISTS idx_log_records_group ON log_records("group");`,
+		`CREATE INDEX IF NOT EXISTS idx_log_records_status_code ON log_records(status_code);`,
+		`CREATE INDEX IF NOT EXISTS idx_log_records_created_key ON log_records(created_at, key_id);`,
+	}
+	for _, stmt := range stmts {
+		if err := db.Exec(stmt).Error; err != nil {
+			return fmt.Errorf("ensure log indexes: %w", err)
+		}
+	}
+	return nil
+}

internal/service/logger.go

@@ -2,6 +2,7 @@ package service
 
 import (
 	"context"
+	"expvar"
 	"log/slog"
 	"time"
 
@@ -9,6 +10,11 @@ import (
 	"gorm.io/gorm"
 )
 
+var (
+	logBatchWriteTotal = expvar.NewInt("log_write_batch_total")
+	logQueueDropped    = expvar.NewInt("log_queue_dropped_total")
+)
+
 // LogWriter batches log records to reduce IO overhead.
 type LogWriter struct {
 	ch            chan model.LogRecord
@@ -48,6 +54,8 @@ func (w *LogWriter) Start(ctx context.Context) {
 			}
 			if err := w.db.Create(&buf).Error; err != nil {
 				slog.Default().Error("log batch insert failed", "err", err)
+			} else {
+				logBatchWriteTotal.Add(1)
 			}
 			buf = buf[:0]
 		}
@@ -75,5 +83,6 @@ func (w *LogWriter) Write(rec model.LogRecord) {
 	case w.ch <- rec:
 	default:
 		// drop to avoid blocking hot path
+		logQueueDropped.Add(1)
 	}
 }