如何使用 Envoy 和 Grpc_web 连接 go grpc 服务器与 dart grpc 客户端

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我是 grpc_web 和 envoy 的新手。

请帮我设置以下内容，

1. grpc_go 服务器作为 docker 容器在 ec2 实例上运行
2. dart web 客户端正在本地 pc 上运行
3. 需要从 dart web 应用向 grpc_go 服务器发出 grpc 调用请求
4. 使用 envoy 代理来转发请求。 envoy 代理作为容器在同一个 ec2 实例中运行

我收到以下错误“响应：null，预告片：{access-control-allow-credentials：true，access-control-allow-origin：http://127.0.0.1:9000，变化：origin} ）”。

grpc_go：

package main

import (
"context"
"flag"
"fmt"
"log"
"net"

"google.golang.org/grpc"
pb "google.golang.org/grpc/examples/helloworld/helloworld"
)

var (
  port = flag.int("port", 50051, "the server port")
)

// server is used to implement helloworld.greeterserver.
type server struct {
   pb.unimplementedgreeterserver
}

// sayhello implements helloworld.greeterserver
func (s *server) sayhello(ctx context.context, in *pb.hellorequest) (*pb.helloreply, error) {
   log.printf("received: %v", in.getname())
   return &pb.helloreply{message: "hello " + in.getname()}, nil
}

func (s *server) sayhelloagain(ctx context.context, in *pb.hellorequest) (*pb.helloreply, 
error) 
{
   return &pb.helloreply{message: "hello again " + in.getname()}, nil
}

func main() {
flag.parse()
lis, err := net.listen("tcp", fmt.sprintf(":%d", *port))
if err != nil {
    log.fatalf("failed to listen: %v", err)
}
s := grpc.newserver()
pb.registergreeterserver(s, &server{})
log.printf("server listening at %v", lis.addr())
if err := s.serve(lis); err != nil {
    log.fatalf("failed to serve: %v", err)
 }
}

grpc_dart_client：

import 'package:grpc/grpc_web.dart';
import 'package:grpc_web/app.dart';
import 'package:grpc_web/src/generated/echo.pbgrpc.dart';

void main() {
  final channel = grpcwebclientchannel.xhr(uri.parse('http://ec2-ip:8080'));
  final service = echoserviceclient(channel);
  final app = echoapp(service);

  final button = queryselector('#send') as buttonelement;
  button.onclick.listen((e) async {
    final msg = queryselector('#msg') as textinputelement;
    final value = msg.value!.trim();
    msg.value = '';

    if (value.isempty) return;

    if (value.indexof(' ') > 0) {
      final countstr = value.substring(0, value.indexof(' '));
      final count = int.tryparse(countstr);

      if (count != null) {
        app.repeatecho(value.substring(value.indexof(' ') + 1), count);
      } else {
        app.echo(value);
      }
    } else {
      app.echo(value);
    }
  });
}

envoy.yaml：

access_log_path: /tmp/admin_access.log
  address:
    socket_address: { address: 0.0.0.0, port_value: 9901 }

static_resources:
  listeners:
  - name: listener_0
    address:
      socket_address: { address: 0.0.0.0, port_value: 8080 }
    filter_chains:
    - filters:
      - name: envoy.filters.network.http_connection_manager
        typed_config:
          "@type": type.googleapis.com/envoy.extensions.filters.network.http_connection_manager.v3.httpconnectionmanager
          codec_type: auto
          stat_prefix: ingress_http
          route_config:
            name: local_route
            virtual_hosts:
            - name: local_service
              domains: ["*"]
              routes:
              - match: { prefix: "/" }
                route:
                  cluster: echo_service
                  timeout: 0s
                  max_stream_duration:
                    grpc_timeout_header_max: 0s
              cors:
                allow_origin_string_match:
                - prefix: "*"
                allow_methods: get, put, delete, post, options
                allow_headers: keep-alive,user-agent,cache-control,content-type,content-transfer-encoding,custom-header-1,x-accept-content-transfer-encoding,x-accept-response-streaming,x-user-agent,x-grpc-web,grpc-timeout
                max_age: "1728000"
                expose_headers: custom-header-1,grpc-status,grpc-message
          http_filters:
          - name: envoy.filters.http.grpc_web
          - name: envoy.filters.http.cors
          - name: envoy.filters.http.router
  clusters:
  - name: echo_service
    connect_timeout: 0.25s
    type: logical_dns
    http2_protocol_options: {}
    lb_policy: round_robin
    load_assignment:
      cluster_name: cluster_0
      endpoints:
        - lb_endpoints:
            - endpoint:
                address:
                  socket_address:
                    address: app
                    port_value: 50051

grpc_go_docker_file：

# install git.
# git is required for fetching the dependencies.
run apk update && apk add --no-cache git
workdir /app
copy go.mod go.sum ./
run go mod download
copy . .
run cgo_enabled=0 goos=linux go build -a -installsuffix cgo -o main .

# start a new stage from scratch
from alpine:latest
run apk --no-cache add ca-certificates

workdir /root/

# copy the pre-built binary file from the previous stage. observe we also copied the .env file
copy --from=builder /app/main .
# expose port 50051 to the outside world
expose 50051

cmd ["./main"]

envoy_docker：

COPY envoy.yaml /etc/envoy/envoy.yaml

CMD /usr/local/bin/envoy -c /etc/envoy/envoy.yaml -l trace --log-path /tmp/envoy_info.log

我已经卡了两天多了，请帮帮我。提前致谢

正确答案

谢谢大家的回复。

我使用 ec2 实例的 ip 修复了此问题。

clusters:
  - name: echo_service
    connect_timeout: 0.25s
    type: logical_dns
    http2_protocol_options: {}
    lb_policy: round_robin
    load_assignment:
      cluster_name: cluster_0
      endpoints:
        - lb_endpoints:
            - endpoint:
                address:
                  socket_address:
                    address: app
                    port_value: 50051

我使用了 ec2 实例的 ip 和容器端口，而不是 envoy.yaml 中的容器“地址：app”（app 是容器名称），现在 envoy 正在将请求转发到服务器。

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