Merge lp:~marix/duplicity/azure-storage-0.30.0-plus into lp:~duplicity-team/duplicity/0.8-series

[Matthias Bach]

This branch make the Azure backend compatible with version 0.30.0 and up of the underlying azure-storage package.

Linux distributions won't ship older version of azure-storage forever. Thus duplicity will no longer be usable on newer distributions as long as it does not support current versions of the azure-storage package.

It can be easily tested by starting a backup to an azure bucket having a recent version of azure-storage installed. E.g. in a test virtualenv:
* pip install -U azure-storage
* duplicity <some dir> azure://<some container>

[Matthias Bach (marix)]

This is the first time on contribute on Launchpad and on a project using Bazaar. Thus, I am sorry in case I missed some some commonly known contribution guidelines. Just let me know and I'll adjust the contribution.

[lp:~marix/duplicity/azure-storage-0.30.0-plus]

1179. By Matthias Bach on 2017-02-14

Fix backup creation using azure-storage > 0.30.0

The previous fix only fixed restore and verification of backups.

=== modified file 'duplicity/backends/azurebackend.py'
--- duplicity/backends/azurebackend.py	2016-05-11 21:07:04 +0000
+++ duplicity/backends/azurebackend.py	2017-02-14 15:41:50 +0000
@@ -44,7 +44,11 @@
                 self.AzureConflictError = azure.WindowsAzureConflictError
             else:
                 # v1.0.0 and above
-                from azure.storage.blob import BlobService
+                import azure.storage.blob
+                if hasattr(azure.storage.blob, 'BlobService'):
+                    from azure.storage.blob import BlobService
+                else:
+                    from azure.storage.blob.blockblobservice import BlockBlobService as BlobService
                 self.AzureMissingResourceError = azure.common.AzureMissingResourceHttpError
                 self.AzureConflictError = azure.common.AzureConflictHttpError
         except ImportError:
@@ -72,7 +76,10 @@
 
     def _put(self, source_path, remote_filename):
         # https://azure.microsoft.com/en-us/documentation/articles/storage-python-how-to-use-blob-storage/#upload-a-blob-into-a-container
-        self.blob_service.put_block_blob_from_path(self.container, remote_filename, source_path.name)
+        try:
+            self.blob_service.create_blob_from_path(self.container, remote_filename, source_path.name)
+        except AttributeError:  # Old versions use a different method name
+            self.blob_service.put_block_blob_from_path(self.container, remote_filename, source_path.name)
 
     def _get(self, remote_filename, local_path):
         # https://azure.microsoft.com/en-us/documentation/articles/storage-python-how-to-use-blob-storage/#download-blobs
@@ -96,7 +103,12 @@
 
     def _query(self, filename):
         prop = self.blob_service.get_blob_properties(self.container, filename)
-        return {'size': int(prop['content-length'])}
+        try:
+            info = {'size': int(prop.properties.content_length)}
+        except AttributeError:
+            # old versions directly returned the properties
+            info = {'size': int(prop['content-length'])}
+        return info
 
     def _error_code(self, operation, e):
         if isinstance(e, self.AzureMissingResourceError):