Merge pull request #5 from fjelltopp/handle_s3_403

wrc104 Handle S3 403

.github/workflows/test.yaml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        python-version: [ 3.7, 3.8 ]
+        python-version: [ 3.8 ]
     steps:
       - uses: actions/checkout@v2
       - name: Install Python 3

.travis.yml

@@ -1,7 +1,6 @@
 language: python
 
 python:
-  - 3.7
   - 3.8
 
 env:

giftless/error_handling.py

@@ -2,9 +2,12 @@
 
 See https://github.com/git-lfs/git-lfs/blob/master/docs/api/batch.md#response-errors
 """
+import logging
+
 from werkzeug.exceptions import default_exceptions
 
 from .representation import output_git_lfs_json
+from .storage.exc import AccessDenied
 
 
 class ApiErrorHandler:
@@ -17,11 +20,25 @@ def init_app(self, app):
         for code in default_exceptions:
             app.errorhandler(code)(self.error_as_json)
 
+        # Specifically handle AccessDenied with a JSON response and 403 status
+        app.errorhandler(AccessDenied)(self.access_denied_as_json)
+
     @classmethod
     def error_as_json(cls, ex):
         """Handle errors by returning a JSON response
+        only maps HTTP-based exceptions from werkzeug.exceptions (like NotFound or Forbidden)
         """
+        log = logging.getLogger(__name__)
         code = ex.code if hasattr(ex, 'code') else 500
         data = {"message": str(ex)}
+        log.debug(f"Returning error response: {data} with status {code}")
 
         return output_git_lfs_json(data=data, code=code)
+
+    @classmethod
+    def access_denied_as_json(cls, ex):
+        """Handle AccessDenied by returning a JSON response with 403 status"""
+        log = logging.getLogger(__name__)
+        log.debug("Returning error response of AccessDenied with status 403")
+        data = ex.as_dict()
+        return output_git_lfs_json(data=data, code=403)

giftless/storage/amazon_s3.py

@@ -5,7 +5,7 @@
 import botocore  # type: ignore
 
 from giftless.storage import ExternalStorage, StreamingStorage
-from giftless.storage.exc import ObjectNotFound
+from giftless.storage.exc import AccessDenied, ObjectNotFound
 from giftless.util import safe_filename
 
 
@@ -22,7 +22,13 @@ def __init__(self, bucket_name: str, path_prefix: Optional[str] = None, **_):
     def get(self, prefix: str, oid: str) -> Iterable[bytes]:
         if not self.exists(prefix, oid):
             raise ObjectNotFound()
-        result: Iterable[bytes] = self._s3_object(prefix, oid).get()['Body']
+        try:
+            result: Iterable[bytes] = self._s3_object(prefix, oid).get()['Body']
+        except botocore.exceptions.ClientError as e:
+            if e.response['Error']['Code'] in ("403", "AccessDenied"):
+                raise AccessDenied()
+            else:
+                raise e
         return result
 
     def put(self, prefix: str, oid: str, data_stream: BinaryIO) -> int:
@@ -38,7 +44,7 @@ def upload_callback(size):
     def exists(self, prefix: str, oid: str) -> bool:
         try:
             self.get_size(prefix, oid)
-        except ObjectNotFound:
+        except (ObjectNotFound, AccessDenied):
             return False
         return True
 
@@ -48,6 +54,8 @@ def get_size(self, prefix: str, oid: str) -> int:
         except botocore.exceptions.ClientError as e:
             if e.response['Error']['Code'] == "404":
                 raise ObjectNotFound()
+            elif e.response['Error']['Code'] in ("403", "AccessDenied"):
+                raise AccessDenied()
             else:
                 raise e
         return result

giftless/storage/exc.py

@@ -19,3 +19,7 @@ class ObjectNotFound(StorageError):
 
 class InvalidObject(StorageError):
     code = 422
+
+
+class AccessDenied(StorageError):
+    code = 403