[grpc] Using gRPC multiprocessing.

Author: arturgontijo

.gitignore

@@ -102,3 +102,6 @@ venv.bak/
 
 # mypy
 .mypy_cache/
+
+*_pb2.py
+*_pb2_grpc.py

requirements.txt

@@ -1,2 +1,2 @@
-grpcio>=1.14.2
+grpcio>=1.14.2 --no-binary grpcio
 grpcio-tools>=1.14.1

run_example_service.py

@@ -11,27 +11,37 @@
 
 from service import registry
 
-logging.basicConfig(level=10, format="%(asctime)s - [%(levelname)8s] - %(name)s - %(message)s")
+logging.basicConfig(level=10, format="%(asctime)s - [%(levelname)8s] - "
+                    "%(name)s - %(message)s")
 log = logging.getLogger("run_example_service")
 
 
 def main():
     parser = argparse.ArgumentParser(description="Run services")
-    parser.add_argument("--no-daemon", action="store_false", dest="run_daemon", help="do not start the daemon")
+    parser.add_argument("--no-daemon",
+                        action="store_false",
+                        dest="run_daemon",
+                        help="do not start the daemon")
     parser.add_argument("--daemon-config",
                         dest="daemon_config",
                         help="Path of daemon configuration file, without config it won't be started",
-                        required=False
-                        )
-    parser.add_argument("--ssl", action="store_true", dest="run_ssl", help="start the daemon with SSL")
+                        required=False)
+    parser.add_argument("--ssl",
+                        action="store_true",
+                        dest="run_ssl",
+                        help="start the daemon with SSL")
     args = parser.parse_args()
     root_path = pathlib.Path(__file__).absolute().parent
 
     # All services modules go here
     service_modules = ["service.example_service"]
 
     # Call for all the services listed in service_modules
-    all_p = start_all_services(root_path, service_modules, args.run_daemon, args.daemon_config, args.run_ssl)
+    all_p = start_all_services(root_path,
+                               service_modules,
+                               args.run_daemon,
+                               args.daemon_config,
+                               args.run_ssl)
 
     # Continuous checking all subprocess
     try:
@@ -53,10 +63,12 @@ def start_all_services(cwd, service_modules, run_daemon, daemon_config, run_ssl)
     snetd will start with configs from "snetd.config.json"
     """
     all_p = []
-    for i, service_module in enumerate(service_modules):
+    for _, service_module in enumerate(service_modules):
         service_name = service_module.split(".")[-1]
-        log.info("Launching {} on port {}".format(str(registry[service_name]), service_module))
-        all_p += start_service(cwd, service_module, run_daemon, daemon_config, run_ssl)
+        log.info("Launching {} on port {}".format(str(registry[service_name]),
+                                                  service_module))
+        all_p += start_service(cwd, service_module,
+                               run_daemon, daemon_config, run_ssl)
     return all_p
 
 
@@ -80,13 +92,17 @@ def add_ssl_configs(conf):
         if daemon_config:
             all_p.append(start_snetd(str(cwd), daemon_config))
         else:
-            for idx, config_file in enumerate(glob.glob("./snetd_configs/*.json")):
+            for _, config_file in enumerate(glob.glob("./snetd_configs/*.json")):
                 if run_ssl:
                     add_ssl_configs(config_file)
                 all_p.append(start_snetd(str(cwd), config_file))
     service_name = service_module.split(".")[-1]
     grpc_port = registry[service_name]["grpc"]
-    p = subprocess.Popen([sys.executable, "-m", service_module, "--grpc-port", str(grpc_port)], cwd=str(cwd))
+    p = subprocess.Popen([
+        sys.executable,
+        "-m", service_module,
+        "--grpc-port", str(grpc_port)],
+       cwd=str(cwd))
     all_p.append(p)
     return all_p
 

service/common.py

@@ -1,18 +1,29 @@
-import sys
+from concurrent import futures
+import contextlib
+import datetime
 import logging
+import multiprocessing
+import time
+import socket
+import sys
 
+import argparse
+import os.path
 import grpc
-import concurrent.futures as futures
 
-import service.common
+from service import registry
 
 # Importing the generated codes from buildproto.sh
 import service.service_spec.example_service_pb2_grpc as grpc_bt_grpc
 from service.service_spec.example_service_pb2 import Result
 
-logging.basicConfig(level=10, format="%(asctime)s - [%(levelname)8s] - %(name)s - %(message)s")
-log = logging.getLogger("example_service")
+logging.basicConfig(level=10, format="%(asctime)s - [%(levelname)8s]"
+                    " - %(name)s - %(message)s")
+_LOGGER = logging.getLogger("example_service")
 
+_ONE_DAY = datetime.timedelta(days=1)
+_PROCESS_COUNT = multiprocessing.cpu_count()
+_THREAD_CONCURRENCY = _PROCESS_COUNT
 
 """
 Simple arithmetic service to test the Snet Daemon (gRPC), dApp and/or Snet-CLI.
@@ -41,7 +52,6 @@
         value: 924.0
 """
 
-
 # Create a class to be added to the gRPC server
 # derived from the protobuf codes.
 class CalculatorServicer(grpc_bt_grpc.CalculatorServicer):
@@ -50,7 +60,7 @@ def __init__(self):
         self.b = 0
         self.result = 0
         # Just for debugging purpose.
-        log.debug("CalculatorServicer created")
+        _LOGGER.debug("CalculatorServicer created")
 
     # The method that will be exposed to the snet-cli call command.
     # request: incoming data
@@ -64,7 +74,7 @@ def add(self, request, context):
         self.result = Result()
 
         self.result.value = self.a + self.b
-        log.debug("add({},{})={}".format(self.a, self.b, self.result.value))
+        _LOGGER.debug("add({},{})={}".format(self.a, self.b, self.result.value))
         return self.result
 
     def sub(self, request, context):
@@ -73,7 +83,7 @@ def sub(self, request, context):
 
         self.result = Result()
         self.result.value = self.a - self.b
-        log.debug("sub({},{})={}".format(self.a, self.b, self.result.value))
+        _LOGGER.debug("sub({},{})={}".format(self.a, self.b, self.result.value))
         return self.result
 
     def mul(self, request, context):
@@ -82,7 +92,7 @@ def mul(self, request, context):
 
         self.result = Result()
         self.result.value = self.a * self.b
-        log.debug("mul({},{})={}".format(self.a, self.b, self.result.value))
+        _LOGGER.debug("mul({},{})={}".format(self.a, self.b, self.result.value))
         return self.result
 
     def div(self, request, context):
@@ -91,10 +101,18 @@ def div(self, request, context):
 
         self.result = Result()
         self.result.value = self.a / self.b
-        log.debug("div({},{})={}".format(self.a, self.b, self.result.value))
+        _LOGGER.debug("div({},{})={}".format(self.a, self.b, self.result.value))
         return self.result
 
 
+def wait_forever(server):
+    try:
+        while True:
+            time.sleep(_ONE_DAY.total_seconds())
+    except KeyboardInterrupt:
+        server.stop(None)
+
+
 # The gRPC serve function.
 #
 # Params:
@@ -103,17 +121,54 @@ def div(self, request, context):
 #
 # Add all your classes to the server here.
 # (from generated .py files by protobuf compiler)
-def serve(max_workers=10, port=7777):
-    server = grpc.server(futures.ThreadPoolExecutor(max_workers=max_workers))
+def run_server(grpc_port=7777):
+    options = (('grpc.so_reuseport', 1),)
+    server = grpc.server(
+        futures.ThreadPoolExecutor(max_workers=_THREAD_CONCURRENCY,),
+        options=options)
     grpc_bt_grpc.add_CalculatorServicer_to_server(CalculatorServicer(), server)
-    server.add_insecure_port("[::]:{}".format(port))
-    return server
+    server.add_insecure_port("[::]:{}".format(grpc_port))
+    server.start()
+    wait_forever(server)
+
+
+@contextlib.contextmanager
+def reserve_port(grpc_port=7777):
+    """Find and reserve a port for all subprocesses to use."""
+    sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
+    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
+    if sock.getsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT) == 0:
+        raise RuntimeError("Failed to set SO_REUSEPORT.")
+    sock.bind(('', grpc_port))
+    try:
+        yield sock.getsockname()[1]
+    finally:
+        sock.close()
+
+def main():
+    """ Runs the gRPC server to communicate with the SNET Daemon. """
+    parser = argparse.ArgumentParser(prog=__file__)
+    service_name = os.path.splitext(os.path.basename(__file__))[0]
+    parser.add_argument("--grpc-port",
+                        help="port to bind gRPC service to",
+                        default=registry[service_name]['grpc'],
+                        type=int,
+                        required=False)
+    args = parser.parse_args(sys.argv[1:])
+    with reserve_port(args.grpc_port) as port:
+        _LOGGER.debug("Binding to port '%s'", port)
+        sys.stdout.flush()
+        workers = []
+        for _ in range(_PROCESS_COUNT):
+            # NOTE: It is imperative that the worker subprocesses be forked before
+            # any gRPC servers start up. See
+            # https://github.com/grpc/grpc/issues/16001 for more details.
+            worker = multiprocessing.Process(target=run_server, args=(port,))
+            worker.start()
+            workers.append(worker)
+        for worker in workers:
+            worker.join()
 
 
 if __name__ == "__main__":
-    """
-    Runs the gRPC server to communicate with the Snet Daemon.
-    """
-    parser = service.common.common_parser(__file__)
-    args = parser.parse_args(sys.argv[1:])
-    service.common.main_loop(serve, args)
+    main()

service/example_service.py

@@ -16,9 +16,11 @@
                 test_flag = True
 
         # Example Service - Arithmetic
-        endpoint = input("Endpoint (localhost:{}): ".format(registry["example_service"]["grpc"])) if not test_flag else ""
+        endpoint = input("Endpoint (localhost:{}): ".format(
+            registry["example_service"]["grpc"])) if not test_flag else ""
         if endpoint == "":
-            endpoint = "localhost:{}".format(registry["example_service"]["grpc"])
+            endpoint = "localhost:{}".format(
+                registry["example_service"]["grpc"])
 
         grpc_method = input("Method (add|sub|mul|div): ") if not test_flag else "mul"
         a = float(input("Number 1: ") if not test_flag else "12")