Async python client

src/funnel/main.py

@@ -1,19 +1,22 @@
-from contextlib import contextmanager
+import asyncio
 import logging
 import time
-from typing import Generator, Optional
+from contextlib import asynccontextmanager
+from typing import AsyncGenerator, Optional
+
 import grpc
-from stubs.serve_segments_pb2_grpc import ServeSegmentsStub
+
 from stubs.serve_segments_pb2 import (
     GetHoursRequest,
     GetHoursResponse,
+    GetMillisecondsRequest,
+    GetMillisecondsResponse,
     GetMinutesRequest,
     GetMinutesResponse,
     GetSecondsRequest,
     GetSecondsResponse,
-    GetMillisecondsRequest,
-    GetMillisecondsResponse,
 )
+from stubs.serve_segments_pb2_grpc import ServeSegmentsStub
 
 SERVE_CURRENTTIME_HOST = "localhost"
 SERVE_CURRENTTIME_PORT = 50000
@@ -23,46 +26,62 @@ SERVE_SEGMENTS_PORT = 50001
 TIMEZONE = "Europe/Zagreb"
 
 
-@contextmanager
-def get_serve_segments_stub() -> Generator[ServeSegmentsStub, None, None]:
-    with grpc.insecure_channel(
+@asynccontextmanager
+async def get_serve_segments_stub() -> AsyncGenerator[ServeSegmentsStub, None]:
+    """Connect to segments server and create stub"""
+    async with grpc.aio.insecure_channel(
         f"{SERVE_SEGMENTS_HOST}:{SERVE_SEGMENTS_PORT}"
     ) as channel:
-        stub = ServeSegmentsStub(channel)
-        yield stub
+        yield ServeSegmentsStub(channel)
 
 
-def get_hours(stub: ServeSegmentsStub) -> Optional[int]:
-    response: GetHoursResponse = stub.GetHours(GetHoursRequest(timezone=TIMEZONE))
+async def get_hours(stub: ServeSegmentsStub) -> Optional[int]:
+    response: GetHoursResponse = await stub.GetHours(GetHoursRequest(timezone=TIMEZONE))
     return response.hours
 
 
-def get_minutes(stub: ServeSegmentsStub) -> Optional[int]:
-    response: GetMinutesResponse = stub.GetMinutes(GetMinutesRequest(timezone=TIMEZONE))
+async def get_minutes(stub: ServeSegmentsStub) -> Optional[int]:
+    response: GetMinutesResponse = await stub.GetMinutes(
+        GetMinutesRequest(timezone=TIMEZONE)
+    )
     return response.minutes
 
 
-def get_seconds(stub: ServeSegmentsStub) -> Optional[int]:
-    response: GetSecondsResponse = stub.GetSeconds(GetSecondsRequest(timezone=TIMEZONE))
+async def get_seconds(stub: ServeSegmentsStub) -> Optional[int]:
+    response: GetSecondsResponse = await stub.GetSeconds(
+        GetSecondsRequest(timezone=TIMEZONE)
+    )
     return response.seconds
 
 
-def get_milliseconds(stub: ServeSegmentsStub) -> Optional[int]:
-    response: GetMillisecondsResponse = stub.GetMilliseconds(
+async def get_milliseconds(stub: ServeSegmentsStub) -> Optional[int]:
+    response: GetMillisecondsResponse = await stub.GetMilliseconds(
         GetMillisecondsRequest(timezone=TIMEZONE)
     )
     return response.milliseconds
 
 
-def run():
-    with get_serve_segments_stub() as stub:
+async def main():
+    async with get_serve_segments_stub() as stub:
         while True:
             t = time.perf_counter()
 
-            hours = get_hours(stub)
-            minutes = get_minutes(stub)
-            seconds = get_seconds(stub)
-            milliseconds = get_milliseconds(stub)
+            # create tasks
+            task_hours = asyncio.create_task(get_hours(stub))
+            task_minutes = asyncio.create_task(get_minutes(stub))
+            task_seconds = asyncio.create_task(get_seconds(stub))
+            task_milliseconds = asyncio.create_task(get_milliseconds(stub))
+
+            # exec tasks asynchronously
+            await asyncio.gather(
+                task_hours, task_minutes, task_seconds, task_milliseconds
+            )
+
+            # get results
+            hours = task_hours.result()
+            minutes = task_minutes.result()
+            seconds = task_seconds.result()
+            milliseconds = task_milliseconds.result()
 
             t = time.perf_counter() - t
 
@@ -73,4 +92,4 @@ def run():
 
 if __name__ == "__main__":
     logging.basicConfig()
-    run()
+    asyncio.run(main())

src/serve_segments/main.go

@@ -31,21 +31,12 @@ type currentTimeResponse struct {
 	formatted_time string
 }
 
-func GetCurrentTime(timezone string) currentTimeResponse {
-	conn, err := grpc.Dial(
-		fmt.Sprintf("%s:%d", SERVE_CURRENTTIME_HOST, SERVE_CURRENTTIME_PORT),
-		grpc.WithTransportCredentials(insecure.NewCredentials()),
-	)
-	if err != nil {
-		log.Fatalf("did not connect: %v", err)
-	}
-	defer conn.Close()
-	c := pb_get_currenttime.NewServeCurrentTimeServiceClient(conn)
+var serveCurrentTimeServiceClient pb_get_currenttime.ServeCurrentTimeServiceClient
 
-	// Contact the server and print out its response.
+func GetCurrentTime(timezone string) currentTimeResponse {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
 	defer cancel()
-	r, err := c.GetCurrentTime(
+	r, err := serveCurrentTimeServiceClient.GetCurrentTime(
 		ctx,
 		&pb_get_currenttime.GetCurrentTimeRequest{Timezone: timezone},
 	)
@@ -53,14 +44,13 @@ func GetCurrentTime(timezone string) currentTimeResponse {
 		log.Fatalf("could not greet: %v", err)
 	}
 
-	result := currentTimeResponse{
+	return currentTimeResponse{
 		hours:          r.Hours,
 		minutes:        r.Minutes,
 		seconds:        r.Seconds,
 		milliseconds:   r.Milliseconds,
 		formatted_time: r.FormattedTime,
 	}
-	return result
 }
 
 func (s *grpc_server) GetHours(
@@ -105,9 +95,23 @@ func serve() {
 		log.Fatalf("failed to listen: %v", err)
 	}
 
+	// create ServeSegments server
 	server := grpc.NewServer()
 	pb_serve_segments.RegisterServeSegmentsServer(server, &grpc_server{})
 	log.Printf("server listening at %v", lis.Addr())
+
+	// create connection to ServeCurrentTime server
+	getCurrentTimeConn, err := grpc.Dial(
+		fmt.Sprintf("%s:%d", SERVE_CURRENTTIME_HOST, SERVE_CURRENTTIME_PORT),
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+	)
+	if err != nil {
+		log.Fatalf("did not connect: %v", err)
+	}
+	defer getCurrentTimeConn.Close()
+	// create client
+	serveCurrentTimeServiceClient = pb_get_currenttime.NewServeCurrentTimeServiceClient(getCurrentTimeConn)
+
 	if err := server.Serve(lis); err != nil {
 		log.Fatalf("failed to serve: %v", err)
 	}