fix: make S3 connection pool size configurable

Add s3_max_pool_connections setting (default 50) to SandboxStoreSettings,
configurable via DIRACX_SANDBOX_STORE_S3_MAX_POOL_CONNECTIONS.

Author: chrisburr

diracx-core/src/diracx/core/settings.py

@@ -268,14 +268,25 @@ class SandboxStoreSettings(ServiceSettingsBase):
     This name is used within DIRAC to refer to this sandbox storage
     endpoint in job descriptions and file catalogs.
     """
+
+    s3_max_pool_connections: int = 50
+    """Maximum number of connections in the S3 client connection pool.
+
+    Higher values allow more parallel S3 requests (e.g. during bulk sandbox
+    deletion). Default: 50.
+    """
+
     _client: S3Client = PrivateAttr()
 
     @contextlib.asynccontextmanager
     async def lifetime_function(self) -> AsyncIterator[None]:
         async with get_session().create_client(
             "s3",
             **self.s3_client_kwargs,
-            config=Config(signature_version="v4", max_pool_connections=50),
+            config=Config(
+                signature_version="v4",
+                max_pool_connections=self.s3_max_pool_connections,
+            ),
         ) as self._client:  # type: ignore
             if not await s3_bucket_exists(self._client, self.bucket_name):
                 if not self.auto_create_bucket:

docs/admin/reference/env-variables.md

@@ -148,6 +148,15 @@ Logical name of the Storage Element for the sandbox store.
 This name is used within DIRAC to refer to this sandbox storage
 endpoint in job descriptions and file catalogs.
 
+### `DIRACX_SANDBOX_STORE_S3_MAX_POOL_CONNECTIONS`
+
+*Optional*, default value: `50`
+
+Maximum number of connections in the S3 client connection pool.
+
+Higher values allow more parallel S3 requests (e.g. during bulk sandbox
+deletion). Default: 50.
+
 ## OTELSettings
 
 Settings for the Open Telemetry Configuration.