Added support for buckets with restricted access.

cloudbridge/cloud/providers/aws/services.py

@@ -4,7 +4,7 @@ import string
 
 from boto.ec2.blockdevicemapping import BlockDeviceMapping
 from boto.ec2.blockdevicemapping import BlockDeviceType
-from boto.exception import EC2ResponseError
+from boto.exception import EC2ResponseError, S3ResponseError
 
 from cloudbridge.cloud.base.resources import ClientPagedResultList
 from cloudbridge.cloud.base.resources import ServerPagedResultList
@@ -362,11 +362,26 @@ class AWSObjectStoreService(BaseObjectStoreService):
         Returns a bucket given its ID. Returns ``None`` if the bucket
         does not exist.
         """
-        bucket = self.provider.s3_conn.lookup(bucket_id)
-        if bucket:
+        try:
+            # Make a call to make sure the bucket exists. While this would
+            # normally return a Bucket instance, there's an edge case where a
+            # 403 response can occur when the bucket exists but the
+            # user simply does not have permissions to access it. See below.
+            bucket = self.provider.s3_conn.get_bucket(bucket_id)
             return AWSBucket(self.provider, bucket)
-        else:
-            return None
+        except S3ResponseError as e:
+            # If 403, it means the bucket exists, but the user does not have
+            # permissions to access the bucket. However, limited operations
+            # may be permitted (with a session token for example), so return a
+            # Bucket instance to allow further operations.
+            # http://stackoverflow.com/questions/32331456/using-boto-upload-file-to-s3-
+            # sub-folder-when-i-have-no-permissions-on-listing-fo
+            if e.status == 403:
+                bucket = self.provider.s3_conn.get_bucket(bucket_id,
+                                                          validate=False)
+                return AWSBucket(self.provider, bucket)
+        # For all other responses, it's assumed that the bucket does not exist.
+        return None
 
     def find(self, name, limit=None, marker=None):
         """