Add api for getting all signed tags, separated by delegation

util/tufmetadata/api.py

@@ -66,6 +66,22 @@ class TUFMetadataAPIInterface(object):
     """
     pass
 
+  @abstractmethod
+  def get_all_tags_with_expiration(self, namespace, repository, targets_file=None, targets_map=None):
+    """
+    Gets the tag -> sha mappings of all delegations for a repo, as well as the expiration of the signatures.
+    Does not verify the metadata, this is purely for display purposes.
+    
+    Args:
+      namespace: namespace containing the repository
+      repository: the repo to get tags for
+      targets_file: the specific target or delegation to read from. Default: targets.json
+    
+    Returns:
+      targets
+    """
+    pass
+  
   @abstractmethod
   def delete_metadata(self, namespace, repository):
     """
@@ -111,30 +127,49 @@ class ImplementedTUFMetadataAPI(TUFMetadataAPIInterface):
 
     if not targets_file:
       targets_file = 'targets/releases.json'
-    gun = self._gun(namespace, repository)
 
-    try:
-      response = self._get(gun, targets_file)
-      signed = self._parse_signed(response.json())
-      targets = signed.get('targets')
-      expiration = signed.get('expires')
-    except requests.exceptions.Timeout:
-      logger.exception('Timeout when trying to get metadata for %s', gun)
-      return None, None
-    except requests.exceptions.ConnectionError:
-      logger.exception('Connection error when trying to get metadata for %s', gun)
-      return None, None
-    except (requests.exceptions.RequestException, ValueError):
-      logger.exception('Failed to get metadata for %s', gun)
-      return None, None
-    except Non200ResponseException as ex:
-      logger.exception('Failed request for %s: %s', gun, str(ex))
-      return None, None
-    except InvalidMetadataException as ex:
-      logger.exception('Failed to parse targets from metadata', str(ex))
+    signed = self._get_signed(namespace, repository, targets_file)
+    if not signed:
       return None, None
 
-    return targets, expiration
+    return signed.get('targets'), signed.get('expires')
+  
+  def get_all_tags_with_expiration(self, namespace, repository, targets_file=None, targets_map=None):
+    """
+    Gets the tag -> sha mappings of all delegations for a repo, as well as the expiration of the signatures.
+    Does not verify the metadata, this is purely for display purposes.
+
+    Args:
+      namespace: namespace containing the repository
+      repository: the repo to get tags for
+      targets_file: the specific target or delegation to read from. Default: targets.json
+
+    Returns:
+      targets
+    """
+
+    if not targets_file:
+      targets_file = 'targets.json'
+      
+    if not targets_map:
+      targets_map = {}
+      
+    signed = self._get_signed(namespace, repository, targets_file)
+    if not signed:
+      return None
+
+    if signed.get('targets'):
+      targets_map[targets_file] = {
+        'targets':  signed.get('targets'),
+        'expiration':  signed.get('expires'),
+      }
+
+    delegation_names = [role.get('name') for role in signed.get('delegations').get('roles')]
+
+    for delegation in delegation_names:
+      targets_map = self.get_all_tags_with_expiration(namespace, repository, targets_file=delegation, targets_map=targets_map)
+   
+    return targets_map
 
   def delete_metadata(self, namespace, repository):
     """
@@ -166,6 +201,25 @@ class ImplementedTUFMetadataAPI(TUFMetadataAPIInterface):
 
   def _gun(self, namespace, repository):
     return join(self._gun_prefix, namespace, repository)
+  
+  def _get_signed(self, namespace, repository, targets_file):
+    gun = self._gun(namespace, repository)
+
+    try:
+      response = self._get(gun, targets_file)
+      signed = self._parse_signed(response.json())
+      return signed
+    except requests.exceptions.Timeout:
+      logger.exception('Timeout when trying to get metadata for %s', gun)
+    except requests.exceptions.ConnectionError:
+      logger.exception('Connection error when trying to get metadata for %s', gun)
+    except (requests.exceptions.RequestException, ValueError):
+      logger.exception('Failed to get metadata for %s', gun)
+    except Non200ResponseException as ex:
+      logger.exception('Failed request for %s: %s', gun, str(ex))
+    except InvalidMetadataException as ex:
+      logger.exception('Failed to parse targets from metadata', str(ex))
+    return None
 
   def _parse_signed(self, json_response):
     """ Attempts to parse the targets from a metadata response """