fix: Add async refresh to prevent synchronous refresh in main thread (feast-dev#3812)

fix: Add async refresh to prevent synchronous refresh in main thread for http feature server

Signed-off-by: Hai Nguyen <quanghai.ng1512@gmail.com>

Author: sudohainguyen

sdk/python/feast/cli.py

@@ -663,6 +663,14 @@ def init_command(project_directory, minimal: bool, template: str):
     show_default=True,
     help="Timeout for keep alive",
 )
+@click.option(
+    "--registry_ttl_sec",
+    "-r",
+    help="Number of seconds after which the registry is refreshed",
+    type=click.INT,
+    default=5,
+    show_default=True,
+)
 @click.pass_context
 def serve_command(
     ctx: click.Context,
@@ -673,6 +681,7 @@ def serve_command(
     no_feature_log: bool,
     workers: int,
     keep_alive_timeout: int,
+    registry_ttl_sec: int = 5,
 ):
     """Start a feature server locally on a given port."""
     store = create_feature_store(ctx)
@@ -685,6 +694,7 @@ def serve_command(
         no_feature_log=no_feature_log,
         workers=workers,
         keep_alive_timeout=keep_alive_timeout,
+        registry_ttl_sec=registry_ttl_sec,
     )
 
 

sdk/python/feast/feature_server.py

@@ -1,4 +1,5 @@
 import json
+import threading
 import traceback
 import warnings
 from typing import List, Optional
@@ -44,14 +45,37 @@ class MaterializeIncrementalRequest(BaseModel):
     feature_views: Optional[List[str]] = None
 
 
-def get_app(store: "feast.FeatureStore"):
+def get_app(store: "feast.FeatureStore", registry_ttl_sec: int = 5):
     proto_json.patch()
 
     app = FastAPI()
+    # Asynchronously refresh registry, notifying shutdown and canceling the active timer if the app is shutting down
+    registry_proto = None
+    shutting_down = False
+    active_timer: Optional[threading.Timer] = None
 
     async def get_body(request: Request):
         return await request.body()
 
+    def async_refresh():
+        store.refresh_registry()
+        nonlocal registry_proto
+        registry_proto = store.registry.proto()
+        if shutting_down:
+            return
+        nonlocal active_timer
+        active_timer = threading.Timer(registry_ttl_sec, async_refresh)
+        active_timer.start()
+
+    @app.on_event("shutdown")
+    def shutdown_event():
+        nonlocal shutting_down
+        shutting_down = True
+        if active_timer:
+            active_timer.cancel()
+
+    async_refresh()
+
     @app.post("/get-online-features")
     def get_online_features(body=Depends(get_body)):
         try:
@@ -180,7 +204,10 @@ def materialize_incremental(body=Depends(get_body)):
 
 class FeastServeApplication(gunicorn.app.base.BaseApplication):
     def __init__(self, store: "feast.FeatureStore", **options):
-        self._app = get_app(store=store)
+        self._app = get_app(
+            store=store,
+            registry_ttl_sec=options.get("registry_ttl_sec", 5),
+        )
         self._options = options
         super().__init__()
 
@@ -202,11 +229,13 @@ def start_server(
     no_access_log: bool,
     workers: int,
     keep_alive_timeout: int,
+    registry_ttl_sec: int = 5,
 ):
     FeastServeApplication(
         store=store,
         bind=f"{host}:{port}",
         accesslog=None if no_access_log else "-",
         workers=workers,
         keepalive=keep_alive_timeout,
+        registry_ttl_sec=registry_ttl_sec,
     ).run()

sdk/python/feast/feature_store.py

@@ -2228,6 +2228,7 @@ def serve(
         no_feature_log: bool,
         workers: int,
         keep_alive_timeout: int,
+        registry_ttl_sec: int,
     ) -> None:
         """Start the feature consumption server locally on a given port."""
         type_ = type_.lower()
@@ -2243,6 +2244,7 @@ def serve(
             no_access_log=no_access_log,
             workers=workers,
             keep_alive_timeout=keep_alive_timeout,
+            registry_ttl_sec=registry_ttl_sec,
         )
 
     @log_exceptions_and_usage