fix(flagd): adding events for rpc mode

Signed-off-by: Simon Schrottner <[email protected]>

Author: aepfli

providers/openfeature-provider-flagd/pyproject.toml

@@ -18,7 +18,7 @@ classifiers = [
 keywords = []
 dependencies = [
   "openfeature-sdk>=0.4.0",
-  "grpcio>=1.60.0",
+  "grpcio>=1.68.0",
   "protobuf>=4.25.2",
   "mmh3>=4.1.0",
   "panzi-json-logic>=1.0.1",

providers/openfeature-provider-flagd/src/openfeature/contrib/provider/flagd/provider.py

@@ -69,14 +69,22 @@ def __init__(  # noqa: PLR0913
 
     def setup_resolver(self) -> AbstractResolver:
         if self.config.resolver_type == ResolverType.GRPC:
-            return GrpcResolver(self.config)
+            return GrpcResolver(
+                self.config,
+                self.emit_provider_ready,
+                self.emit_provider_error,
+                self.emit_provider_configuration_changed,
+            )
         elif self.config.resolver_type == ResolverType.IN_PROCESS:
             return InProcessResolver(self.config, self)
         else:
             raise ValueError(
                 f"`resolver_type` parameter invalid: {self.config.resolver_type}"
             )
 
+    def initialize(self, evaluation_context: EvaluationContext) -> None:
+        self.resolver.initialize(evaluation_context)
+
     def shutdown(self) -> None:
         if self.resolver:
             self.resolver.shutdown()

providers/openfeature-provider-flagd/src/openfeature/contrib/provider/flagd/resolvers/__init__.py

@@ -8,6 +8,8 @@
 
 
 class AbstractResolver(typing.Protocol):
+    def initialize(self, evaluation_context: EvaluationContext) -> None: ...
+
     def shutdown(self) -> None: ...
 
     def resolve_boolean_details(

providers/openfeature-provider-flagd/src/openfeature/contrib/provider/flagd/resolvers/grpc.py

@@ -1,3 +1,6 @@
+import logging
+import threading
+import time
 import typing
 
 import grpc
@@ -9,7 +12,9 @@
 )
 
 from openfeature.evaluation_context import EvaluationContext
+from openfeature.event import ProviderEventDetails
 from openfeature.exception import (
+    ErrorCode,
     FlagNotFoundError,
     GeneralError,
     InvalidContextError,
@@ -23,19 +28,95 @@
 
 T = typing.TypeVar("T")
 
+logger = logging.getLogger("openfeature.contrib")
+
 
 class GrpcResolver:
-    def __init__(self, config: Config):
+    MAX_BACK_OFF = 120
+
+    def __init__(
+        self,
+        config: Config,
+        emit_provider_ready: typing.Callable[[ProviderEventDetails], None],
+        emit_provider_error: typing.Callable[[ProviderEventDetails], None],
+        emit_provider_configuration_changed: typing.Callable[
+            [ProviderEventDetails], None
+        ],
+    ):
         self.config = config
+        self.emit_provider_ready = emit_provider_ready
+        self.emit_provider_error = emit_provider_error
+        self.emit_provider_configuration_changed = emit_provider_configuration_changed
         channel_factory = (
             grpc.secure_channel if self.config.tls else grpc.insecure_channel
         )
         self.channel = channel_factory(f"{self.config.host}:{self.config.port}")
         self.stub = evaluation_pb2_grpc.ServiceStub(self.channel)
+        self.retry_backoff_seconds = 0.1
+        self.connected = False
+
+    def initialize(self, evaluation_context: EvaluationContext) -> None:
+        self.connect()
 
     def shutdown(self) -> None:
+        self.active = False
         self.channel.close()
 
+    def connect(self) -> None:
+        self.active = True
+        self.thread = threading.Thread(
+            target=self.listen, daemon=True, name="FlagdGrpcServiceWorkerThread"
+        )
+        self.thread.start()
+
+    def listen(self) -> None:
+        retry_delay = self.retry_backoff_seconds
+        while self.active:
+            request = evaluation_pb2.EventStreamRequest()  # type:ignore[attr-defined]
+            try:
+                logger.debug("Setting up gRPC sync flags connection")
+                for message in self.stub.EventStream(request):
+                    if message.type == "provider_ready":
+                        if not self.connected:
+                            self.emit_provider_ready(
+                                ProviderEventDetails(
+                                    message="gRPC sync connection established"
+                                )
+                            )
+                            self.connected = True
+                            # reset retry delay after successsful read
+                            retry_delay = self.retry_backoff_seconds
+
+                    elif message.type == "configuration_change":
+                        data = MessageToDict(message)["data"]
+                        self.handle_changed_flags(data)
+
+                    if not self.active:
+                        logger.info("Terminating gRPC sync thread")
+                        return
+            except grpc.RpcError as e:
+                logger.error(f"SyncFlags stream error, {e.code()=} {e.details()=}")
+            except ParseError:
+                logger.exception(
+                    f"Could not parse flag data using flagd syntax: {message=}"
+                )
+
+            self.connected = False
+            self.emit_provider_error(
+                ProviderEventDetails(
+                    message=f"gRPC sync disconnected, reconnecting in {retry_delay}s",
+                    error_code=ErrorCode.GENERAL,
+                )
+            )
+            logger.info(f"gRPC sync disconnected, reconnecting in {retry_delay}s")
+            time.sleep(retry_delay)
+            retry_delay = min(2 * retry_delay, self.MAX_BACK_OFF)
+
+    def handle_changed_flags(self, data: typing.Any) -> None:
+        changed_flags = list(data["flags"].keys())
+
+        self.emit_provider_configuration_changed(ProviderEventDetails(changed_flags))
+
     def resolve_boolean_details(
         self,
         key: str,

providers/openfeature-provider-flagd/src/openfeature/contrib/provider/flagd/resolvers/in_process.py

@@ -3,7 +3,7 @@
 from openfeature.evaluation_context import EvaluationContext
 from openfeature.exception import FlagNotFoundError, ParseError
 from openfeature.flag_evaluation import FlagResolutionDetails, Reason
-from openfeature.provider.provider import AbstractProvider
+from openfeature.provider import AbstractProvider
 
 from ..config import Config
 from .process.file_watcher import FileWatcherFlagStore
@@ -26,6 +26,9 @@ def __init__(self, config: Config, provider: AbstractProvider):
             self.config.offline_poll_interval_seconds,
         )
 
+    def initialize(self, evaluation_context: EvaluationContext) -> None:
+        pass
+
     def shutdown(self) -> None:
         self.flag_store.shutdown()
 

providers/openfeature-provider-flagd/tests/e2e/conftest.py

@@ -5,29 +5,22 @@
 from tests.e2e.flagd_container import FlagdContainer
 from tests.e2e.steps import *  # noqa: F403
 
-from openfeature import api
-from openfeature.contrib.provider.flagd import FlagdProvider
-
 JsonPrimitive = typing.Union[str, bool, float, int]
 
 
-@pytest.fixture(autouse=True, scope="package")
-def setup(request, port, image, resolver_type):
+@pytest.fixture(autouse=True, scope="module")
+def setup(request, port, image):
     container: DockerContainer = FlagdContainer(
         image=image,
         port=port,
     )
     # Setup code
     c = container.start()
-    api.set_provider(
-        FlagdProvider(
-            resolver_type=resolver_type,
-            port=int(container.get_exposed_port(port)),
-        )
-    )
 
     def fin():
         c.stop()
 
     # Teardown code
     request.addfinalizer(fin)
+
+    return c.get_exposed_port(port)