Support for concurrent S3 part uploads

app/Extensions/BackupAdapter/Schemas/S3BackupSchema.php

@@ -141,12 +141,15 @@ public function getUploadParts(Backup $backup, int $size): array
             )->getUri()->__toString();
         }
 
+        $maxConcurrentUploads = config('backups.max_concurrent_uploads', BackupRemoteUploadController::MAX_CONCURRENT_UPLOADS);
+
         // Set the upload_id on the backup in the database.
         $backup->update(['upload_id' => $params['UploadId']]);
 
         return [
             'parts' => $parts,
             'part_size' => $maxPartSize,
+            'max_concurrent_uploads' => $maxConcurrentUploads,
         ];
     }
 

app/Http/Controllers/Api/Remote/Backups/BackupRemoteUploadController.php

@@ -22,6 +22,8 @@ class BackupRemoteUploadController extends Controller
 
     public const MAX_MAX_PART_SIZE = 5 * 1024 * 1024 * 1024; // 5 GiB
 
+    public const MAX_CONCURRENT_UPLOADS = 10;
+
     /**
      * BackupRemoteUploadController constructor.
      */

config/backups.php

@@ -16,6 +16,12 @@
     // to 6 hours.  To disable this feature, set the value to `0`.
     'prune_age' => (int) env('BACKUP_PRUNE_AGE', 360),
 
+    // This value defines the maximum amount of concurrent requests PER BACKUP for S3 uploads
+    // The default value is 10.
+    // This value is not guaranteed to be reached (for instance, if there are fewer parts).
+    // If multiple backups are being uploaded to S3 at the same time, each backup may have up to this limit of concurrent uploads.
+    'max_concurrent_uploads' => (int) env('BACKUP_MAX_CONCURRENT_UPLOADS', BackupRemoteUploadController::MAX_CONCURRENT_UPLOADS),
+
     // Defines the backup creation throttle limits for users. In this default example, we allow
     // a user to create two (successful or pending) backups per 10 minutes. Even if they delete
     // a backup it will be included in the throttle count.