Merge pull request #19 from evo-company/add-sync-method-to-client

allow to push defaults during flags preload

.gitignore

@@ -14,4 +14,5 @@ examples/local_config.py
 .pytest_cache
 .lets
 .pdm.toml
-__pypackages__
+__pypackages__
+.DS_Store

README.rst

@@ -27,6 +27,21 @@ Server consists of two services:
 
   - grpclib_ + hiku_
 
+Installation
+~~~~~~~~~~~~
+
+To install client library for synchronous app:
+
+.. code-block:: shell
+
+    $ pip install featureflags-client grpcio
+
+To install client library for asynchronous app:
+
+.. code-block:: shell
+
+    $ pip install featureflags-client grpclib
+
 Development
 ~~~~~~~~~~~
 

client/featureflags/client/flags.py

@@ -95,6 +95,15 @@ def flush(self, delta=timedelta(minutes=1)):
                 ))
         return stats
 
+    @staticmethod
+    def from_defaults(defaults):
+        interval_pb = Timestamp()
+        interval_pb.FromDatetime(datetime.utcnow())
+        return [
+            FlagUsage(name=name, interval=interval_pb, positive_count=0, negative_count=0)
+            for name in defaults
+        ]
+
 
 class Tracer:
     """
@@ -216,3 +225,12 @@ def flags(
         finally:
             if tracer is not None:
                 self._manager.add_trace(tracer)
+
+    def preload(self, timeout=None):
+        """Preload flags from server.
+        This method syncs all flags with server"""
+        self._manager.preload(timeout=timeout, defaults=self._defaults)
+
+    async def preload_async(self, timeout=None):
+        """Async version of `preload` method"""
+        await self._manager.preload(timeout=timeout, defaults=self._defaults)

client/featureflags/client/managers/asyncio.py

@@ -66,8 +66,20 @@ def __init__(self, project, variables, channel, *, loop=None):
                 stacklevel=2,
             )
 
-    async def preload(self, *, timeout=None):
-        await self._exchange(timeout)
+    async def preload(self, *, timeout=None, defaults=None):
+        """
+        Preload flags from the server.
+        :param timeout: timeout in seconds (for grpclib)
+        :param defaults: dict with default values for feature flags.
+                         If passed, all feature flags will be synced with server,
+                         otherwise flags will be synced only when they are accessed
+                         for the first time.
+        """
+        stats = None
+        if defaults is not None:
+            stats = self._stats.from_defaults(defaults)
+
+        await self._exchange(timeout, stats)
 
     def start(self):
         if self._exchange_task is not None:
@@ -105,8 +117,11 @@ async def _exchange_coro(self):
                 await asyncio.sleep(interval)
                 continue
 
-    async def _exchange(self, timeout):
-        request = self._state.get_request(self._stats.flush())
+    async def _exchange(self, timeout, flags_usage=None):
+        if flags_usage is None:
+            flags_usage = self._stats.flush()
+
+        request = self._state.get_request(flags_usage)
         log.debug('Exchange request, project: %r, version: %r, stats: %r',
                   request.project, request.version, request.flags_usage)
         reply = await self._stub.Exchange(request, timeout=timeout)

client/featureflags/client/managers/sync.py

@@ -46,11 +46,26 @@ def __init__(self, project, variables, channel):
         self._int_gen.send(None)
         self._next_exchange = datetime.utcnow()
 
-    def preload(self, timeout=None):
-        self._exchange(timeout)
-
-    def _exchange(self, timeout):
-        request = self._state.get_request(self._stats.flush())
+    def preload(self, timeout=None, defaults=None):
+        """
+        Preload flags from the server.
+        :param timeout: timeout in seconds (for grpcio)
+        :param defaults: dict with default values for feature flags.
+                         If passed, all feature flags will be synced with server,
+                         otherwise flags will be synced only when they are accessed
+                         for the first time.
+        """
+        stats = None
+        if defaults is not None:
+            stats = self._stats.from_defaults(defaults)
+
+        self._exchange(timeout, stats)
+
+    def _exchange(self, timeout, flags_usage=None):
+        if flags_usage is None:
+            flags_usage = self._stats.flush()
+
+        request = self._state.get_request(flags_usage)
         log.debug('Exchange request, project: %r, version: %r, stats: %r',
                   request.project, request.version, request.flags_usage)
         reply = self._stub.Exchange(request, timeout=timeout)