fix: fixes s3 event and access logs sending in ProcessController

Fixes #1620

S3 events were not correctly sent by the gateway. For example, actions that don’t include a response payload caused the event emission to be skipped. This has now been fixed — S3 events are sent regardless of whether the response has a payload or if any parsing issues occur later in the `ProcessController` during body parsing.

The fix also ensures that S3 events are sent **only** for specific actions, as intended, instead of being sent for all actions.

Additionally, this update improves server access log handling by covering cases where errors occur during response payload parsing, ensuring such errors are properly reflected in the access logs.

s3api/controllers/base.go

@@ -207,12 +207,32 @@ func ProcessController(ctx *fiber.Ctx, controller Controller, s3action string, s
 			s3err.GetAPIError(s3err.ErrInternalError), "", "", ""))
 	}
 
+	// At this point, the S3 action has succeeded in the backend and
+	// the event has already occurred. This means the S3 event must be sent,
+	// even if unexpected issues arise while further parsing the response payload.
+	if svc.EventSender != nil && opts.EventName != "" {
+		svc.EventSender.SendEvent(ctx, s3event.EventMeta{
+			BucketOwner: opts.BucketOwner,
+			ObjectSize:  opts.ObjectSize,
+			ObjectETag:  opts.ObjectETag,
+			VersionId:   opts.VersionId,
+			EventName:   opts.EventName,
+		})
+	}
+
 	if opts.Status == 0 {
 		opts.Status = http.StatusOK
 	}
 
 	// if no data payload is provided, send the response status
 	if response.Data == nil {
+		if svc.Logger != nil {
+			svc.Logger.Log(ctx, nil, []byte{}, s3log.LogMeta{
+				Action:      s3action,
+				BucketOwner: opts.BucketOwner,
+				ObjectSize:  opts.ObjectSize,
+			})
+		}
 		ctx.Status(opts.Status)
 		return nil
 	}
@@ -226,6 +246,13 @@ func ProcessController(ctx *fiber.Ctx, controller Controller, s3action string, s
 	} else {
 		if responseBytes, err = xml.Marshal(response.Data); err != nil {
 			debuglogger.Logf("Internal Error, %v", err)
+			if svc.Logger != nil {
+				svc.Logger.Log(ctx, err, nil, s3log.LogMeta{
+					Action:      s3action,
+					BucketOwner: opts.BucketOwner,
+					ObjectSize:  opts.ObjectSize,
+				})
+			}
 			return ctx.Status(http.StatusInternalServerError).Send(s3err.GetAPIErrorResponse(
 				s3err.GetAPIError(s3err.ErrInternalError), "", "", ""))
 		}
@@ -235,29 +262,19 @@ func ProcessController(ctx *fiber.Ctx, controller Controller, s3action string, s
 		}
 	}
 
-	if svc.Logger != nil {
-		svc.Logger.Log(ctx, nil, responseBytes, s3log.LogMeta{
-			Action:      s3action,
-			BucketOwner: opts.BucketOwner,
-			ObjectSize:  opts.ObjectSize,
-		})
-	}
-
-	if svc.EventSender != nil {
-		svc.EventSender.SendEvent(ctx, s3event.EventMeta{
-			BucketOwner: opts.BucketOwner,
-			ObjectSize:  opts.ObjectSize,
-			ObjectETag:  opts.ObjectETag,
-			VersionId:   opts.VersionId,
-			EventName:   opts.EventName,
-		})
-	}
-
 	if ok {
 		if len(responseBytes) > 0 {
 			ctx.Response().Header.Set("Content-Length", fmt.Sprint(len(responseBytes)))
 		}
 
+		if svc.Logger != nil {
+			svc.Logger.Log(ctx, nil, responseBytes, s3log.LogMeta{
+				Action:      s3action,
+				BucketOwner: opts.BucketOwner,
+				ObjectSize:  opts.ObjectSize,
+			})
+		}
+
 		return ctx.Send(responseBytes)
 	}
 
@@ -265,6 +282,13 @@ func ProcessController(ctx *fiber.Ctx, controller Controller, s3action string, s
 	if msglen > maxXMLBodyLen {
 		debuglogger.Logf("XML encoded body len %v exceeds max len %v",
 			msglen, maxXMLBodyLen)
+		if svc.Logger != nil {
+			svc.Logger.Log(ctx, err, []byte{}, s3log.LogMeta{
+				Action:      s3action,
+				BucketOwner: opts.BucketOwner,
+				ObjectSize:  opts.ObjectSize,
+			})
+		}
 		ctx.Status(http.StatusInternalServerError)
 
 		return ctx.Send(s3err.GetAPIErrorResponse(
@@ -277,6 +301,14 @@ func ProcessController(ctx *fiber.Ctx, controller Controller, s3action string, s
 	// Set the Content-Length header
 	ctx.Response().Header.SetContentLength(msglen)
 
+	if svc.Logger != nil {
+		svc.Logger.Log(ctx, nil, responseBytes, s3log.LogMeta{
+			Action:      s3action,
+			BucketOwner: opts.BucketOwner,
+			ObjectSize:  opts.ObjectSize,
+		})
+	}
+
 	return ctx.Send(res)
 }