Make info-provider API backwards-compatible with respect to key_patte…

…rns parameter (#18)

* Make info-provider API backwards-compatible with respect to key_patterns parameter

* Advance version number to 0.12.0

setup.py

@@ -29,7 +29,7 @@
 
 setup(
     name='redis-info-provider',
-    version='0.11.0',
+    version='0.12.0',
     python_requires='>=2.7',
     package_dir={'': 'src'},
     packages=find_packages('src'),

src/redis_info_provider/info_servicer.py

@@ -1,5 +1,7 @@
 from __future__ import print_function
 import time
+import functools
+import warnings
 from .shard_pub import ShardPublisher
 from .redis_shard import InfoType, RedisShard
 import logging
@@ -9,6 +11,37 @@
 logger = logging.getLogger(__name__)
 
 
+def deprecated_alias(**aliases):
+    """
+    Decorator that renames deprecated parameter names of a function to their new names and then calls the function with
+    the new parameter names.
+    :param aliases: Dict[str,str] - mapping of deprecated parameter names to their new names.
+    """
+    def deco(f):
+        @functools.wraps(f)
+        def wrapper(*args, **kwargs):
+            rename_kwargs(f.__name__, kwargs, aliases)
+            return f(*args, **kwargs)
+        return wrapper
+    return deco
+
+
+def rename_kwargs(func_name, kwargs, aliases):
+    """
+    Rename deprecated parameters of kwargs to their new name as as it appears in aliases dict.
+    :param func_name: str (name of function that the decorator is applied to)
+    :param kwargs: Dict[str, str] of arguments the given function was called with
+    :param aliases: Dict[str, str] that maps deprecated parameters to new parameter names
+    :raises TypeError if both an argument and its deprecated alias were received
+    """
+    for alias, new in aliases.items():
+        if alias in kwargs:
+            if new in kwargs:
+                raise TypeError('{} received both {} and {}'.format(func_name, alias, new))
+            warnings.warn('{} is deprecated; use {}'.format(alias, new), DeprecationWarning)
+            kwargs[new] = kwargs.pop(alias)
+
+
 class InfoProviderServicer(object):
     """Implements the InfoProvider RPC interface."""
 
@@ -58,12 +91,15 @@ def _get_shard_with_info(shard_id):
 
         return shard
 
+    @deprecated_alias(key_patterns='keys')
     def GetInfos(self, shard_ids=(), keys=(), allow_partial=False, max_age=0.0):
         # type: (Sequence[str], Sequence[str], bool, float) -> List[InfoType]
 
         """
         Returns a list of info dicts according to the shard-ids and keys
         specified in the query selector.
+        Note: if deprecated parameter "key_patterns" is passed, we use it as "keys" for backwards compatibility.
+        However, filtering by glob-like patterns is no longer supported.
         :param shard_ids: List of shard identifiers to query. If empty, all live
             shards will be returned.
         :param keys: List of exact-match keys to filter for. If not empty, only

tests/test_infoServicer.py

@@ -151,6 +151,18 @@ def test_allow_partial_unknown_shard(self):
                            msg='Expected info_age for shard-2 to be very large')
         six.assertRegex(self, response_dict['shard-2']['meta']['error'], 'shard .* not found')
 
+    def test_backwards_compatibility(self):
+        ShardPublisher.add_shard(self.make_shard('shard-1', info={'dummy1': 'dummy1', 'dummy2': 'dummy2'}))
+        ShardPublisher.add_shard(self.make_shard('shard-2', info={'dummy1': 'dummy1'}))
+
+        response = self.servicer.GetInfos(shard_ids=['shard-1', 'shard-2'], key_patterns=['dummy1'])
+        response_dict = {info['meta']['shard_identifier']: info for info in response}
+        self.assertIn('dummy1', response_dict['shard-1'])
+        self.assertIn('dummy1', response_dict['shard-2'])
+
+        with self.assertRaises(TypeError):
+            self.servicer.GetInfos(shard_ids=['shard-1'], key_patterns=['dummy1'], keys=['dummy1'])
+
     @patch('redis_info_provider.info_servicer.time.time')
     def test_max_age(self, time_mock):
         now = 1545240843.4637716