add content manager for short term credentials

Author: DenisaCG

jupyter_drives/managers/s3.py

@@ -85,15 +85,28 @@ async def mount_drive(self, drive_name):
             S3ContentsManager
         '''
         try :
-            s3_contents_manager = S3ContentsManager(
-                access_key = self._config.access_key_id,
-                secret_access_key = self._config.secret_access_key,
-                endpoint_url = self._config.api_base_url,
-                bucket = drive_name
-            )
-
             # checking if the drive wasn't mounted already
             if self.s3_content_managers[drive_name] is None:
+
+                # dealing with long-term credentials (access key, secret key)
+                if self._config.session_token is None:
+                    s3_contents_manager = S3ContentsManager(
+                    access_key = self._config.access_key_id,
+                    secret_access_key = self._config.secret_access_key,
+                    endpoint_url = self._config.api_base_url,
+                    bucket = drive_name
+                    )
+                
+                # dealing with short-term credentials (access key, secret key, session token)
+                else:
+                    s3_contents_manager = S3ContentsManager(
+                    access_key = self._config.access_key_id,
+                    secret_access_key = self._config.secret_access_key,
+                    session_token = self._config.session_token,
+                    endpoint_url = self._config.api_base_url,
+                    bucket = drive_name
+                    )
+                
                 self.s3_content_managers[drive_name] = s3_contents_manager
 
                 response = {