Simple gRPC envoy configuration

Question

I'm trying to setup a envoy proxy as a gRPC fron end, and can't get it to work, so I'm trying to get to as simple a test setup as possible and build from there, but I can't get that to work either. Here's what my test setup looks like:

Python server (slightly modified gRPC example code)

# greeter_server.py
from concurrent import futures
import time

import grpc

import helloworld_pb2
import helloworld_pb2_grpc

_ONE_DAY_IN_SECONDS = 60 * 60 * 24


class Greeter(helloworld_pb2_grpc.GreeterServicer):

    def SayHello(self, request, context):
        return helloworld_pb2.HelloReply(message='Hello, %s!' % request.name)


def serve():
    server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
    helloworld_pb2_grpc.add_GreeterServicer_to_server(Greeter(), server)
    server.add_insecure_port('[::]:8081')
    server.start()
    try:
        while True:
            time.sleep(_ONE_DAY_IN_SECONDS)
    except KeyboardInterrupt:
        server.stop(0)


if __name__ == '__main__':
    serve()

Python client (slightly modified gRPC example code)

from __future__ import print_function

import grpc

import helloworld_pb2
import helloworld_pb2_grpc


def run():
    # NOTE(gRPC Python Team): .close() is possible on a channel and should be
    # used in circumstances in which the with statement does not fit the needs
    # of the code.
    with grpc.insecure_channel('localhost:9911') as channel:
        stub = helloworld_pb2_grpc.GreeterStub(channel)
        response = stub.SayHello(helloworld_pb2.HelloRequest(name='you'))
    print("Greeter client received: " + response.message)


if __name__ == '__main__':
    run()

And then my two envoy yaml files:

# envoy-hello-server.yaml
static_resources:
  listeners:
  - address:
      socket_address:
        address: 0.0.0.0
        port_value: 8811
    filter_chains:
    - filters:
      - name: envoy.http_connection_manager
        typed_config:
          "@type": type.googleapis.com/envoy.config.filter.network.http_connection_manager.v2.HttpConnectionManager
          codec_type: auto
          stat_prefix: ingress_http
          access_log:
          - name: envoy.file_access_log
            typed_config:
              "@type": type.googleapis.com/envoy.config.accesslog.v2.FileAccessLog
              path: "/dev/stdout"
          route_config:
            name: local_route
            virtual_hosts:
            - name: backend
              domains:
              - "*"
              routes:
              - match:
                  prefix: "/"
                  grpc: {}
                route:
                  cluster: hello_grpc_service
          http_filters:
          - name: envoy.router
            typed_config: {}
  clusters:
  - name: hello_grpc_service
    connect_timeout: 0.250s
    type: strict_dns
    lb_policy: round_robin
    http2_protocol_options: {}
    load_assignment:
      cluster_name: hello_grpc_service
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: hello_grpc_service
                port_value: 8081

admin:
  access_log_path: "/tmp/envoy_hello_server.log"
  address:
    socket_address:
      address: 0.0.0.0
      port_value: 8881

and

# envoy-hello-client.yaml
static_resources:
  listeners:
  - address:
      socket_address:
        address: 0.0.0.0
        port_value: 9911
    filter_chains:
    - filters:
      - name: envoy.http_connection_manager
        typed_config:
          "@type": type.googleapis.com/envoy.config.filter.network.http_connection_manager.v2.HttpConnectionManager
          codec_type: auto
          add_user_agent: true
          access_log:
          - name: envoy.file_access_log
            typed_config:
              "@type": type.googleapis.com/envoy.config.accesslog.v2.FileAccessLog
              path: "/dev/stdout"
          stat_prefix: egress_http
          common_http_protocol_options:
            idle_timeout: 0.840s
          use_remote_address: true
          route_config:
            name: local_route
            virtual_hosts:
            - name: backend
              domains:
              - grpc
              routes:
              - match:
                  prefix: "/"
                route:
                  cluster: backend-proxy
          http_filters:
          - name: envoy.router
            typed_config: {}
  clusters:
  - name: backend-proxy
    type: logical_dns
    dns_lookup_family: V4_ONLY
    lb_policy: round_robin
    connect_timeout: 0.250s
    http_protocol_options: {}
    load_assignment:
      cluster_name: backend-proxy
      endpoints:
      - lb_endpoints:
        - endpoint:
            address:
              socket_address:
                address: hello_grpc_service
                port_value: 8811

admin:
  access_log_path: "/tmp/envoy_hello_client.log"
  address:
    socket_address:
      address: 0.0.0.0
      port_value: 9991

Now, what I expect this would allow is something like hello_client.py (port 9911) -> envoy (envoy-hello-client.yaml) -> envoy (envoy-hello-server.yaml) -> hello_server.py (port 8081)

Instead, what I get is an error from the python client:

$ python3 greeter_client.py 
Traceback (most recent call last):
  File "greeter_client.py", line 35, in 
    run()
  File "greeter_client.py", line 30, in run
    response = stub.SayHello(helloworld_pb2.HelloRequest(name='you'))
  File "/usr/lib/python3/dist-packages/grpc/_channel.py", line 533, in __call__
    return _end_unary_response_blocking(state, call, False, None)
  File "/usr/lib/python3/dist-packages/grpc/_channel.py", line 467, in _end_unary_response_blocking
    raise _Rendezvous(state, None, None, deadline)
grpc._channel._Rendezvous: <_Rendezvous of RPC that terminated with:
    status = StatusCode.UNIMPLEMENTED
    details = ""
    debug_error_string = "{"created":"@1594770575.642032812","description":"Error received from peer","file":"src/core/lib/surface/call.cc","file_line":1017,"grpc_message":"","grpc_status":12}"
>

And in the envoy client log:

[2020-07-14 16:22:10.407][16935][info][main] [external/envoy/source/server/server.cc:652] starting main dispatch loop
[2020-07-14 16:23:25.441][16935][info][runtime] [external/envoy/source/common/runtime/runtime_impl.cc:524] RTDS has finished initialization
[2020-07-14 16:23:25.441][16935][info][upstream] [external/envoy/source/common/upstream/cluster_manager_impl.cc:182] cm init: all clusters initialized
[2020-07-14 16:23:25.441][16935][info][main] [external/envoy/source/server/server.cc:631] all clusters initialized. initializing init manager
[2020-07-14 16:23:25.441][16935][info][config] [external/envoy/source/server/listener_manager_impl.cc:844] all dependencies initialized. starting workers
[2020-07-14 16:23:25.441][16935][warning][main] [external/envoy/source/server/server.cc:537] there is no configured limit to the number of allowed active connections. Set a limit via the runtime key overload.global_downstream_max_connections
[2020-07-14T23:49:35.641Z] "POST /helloworld.Greeter/SayHello HTTP/2" 200 NR 0 0 0 - "10.0.0.56" "grpc-python/1.16.1 grpc-c/6.0.0 (linux; chttp2; gao)" "aa72310a-3188-46b2-8cbf-9448b074f7ae" "localhost:9911" "-"

And nothing in the server log.

Also, weirdly, this is an almost one second delay between when I run the python client and when the log message shows up in the client envoy.

What am I missing to make these two scripts talk via envoy?

Simple gRPC envoy configuration

Answers (1)

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