在使用docker compose的容器之间拒绝API请求的连接

Question

我正在开发一个多容器的Docker应用程序，我想要一个容器使用Docker Compose向其他容器的API发出HTTP请求。我收到连接拒绝错误。

这两个容器都运行ASP.NET Core2.2。我使用的IDE是Visual Studio2017。我在用邮递员测试API调用。

DockerFiles

FROM microsoft/dotnet:2.2-aspnetcore-runtime AS base
WORKDIR /app
EXPOSE 80
EXPOSE 443
...

Docker组合配置：

version: '3.4'

services:
  servicea:
    ...
    ports:
      - "51841:80"
      - "44364:443"
    networks:
      - local

  serviceb:
      ...
    ports:
      - "65112:80"
      - "44359:443"
    networks:
      - local

networks:
  local:
    driver: bridge

服务控制器操作：

[Route("[action]")]
[HttpGet]
public IActionResult foo()
{
   HttpClient client = _clientFactory.CreateClient();

   var result = client.GetAsync("http://serviceb:80/api/bar").Result;
   var response = result.Content.ReadAsStringAsync().Result;

   return new OkObjectResult(response);
}

System.Net.Http.HttpRequestException: Connection refused ---> System.Net.Sockets.SocketException: Connection refused
   at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.CreateConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.WaitForCreatedConnectionAsync(ValueTask`1 creationTask)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)

root@serviceA_id:/app# ping -p 80 serviceb
PATTERN: 0x80
PING serviceb(10.168.0.3) 56(84) bytes of data.
64 bytes from ... (10.168.0.3): icmp_seq=1 ttl=64 time=0.117 ms
64 bytes from ... (10.168.0.3): icmp_seq=2 ttl=64 time=0.101 ms
64 bytes from ... (10.168.0.3): icmp_seq=3 ttl=64 time=0.083 ms
--- serviceb ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2057ms rtt min/avg/max/mdev = 0.083/0.100/0.117/0.016 ms

卷曲

我还可以使用CURL来稳定与API RESTendpoint的连接，但是recieved的Content-Length是0

root@serviceA_id:/app# curl -v http://serviceb/api/bar
*   Trying 10.168.0.3...
* TCP_NODELAY set
* Connected to serviceb (10.168.0.3) port 80 (#0)
> GET /api/bar/ HTTP/1.1
> Host: serviceb
> User-Agent: curl/7.52.1
> Accept: */*
>
< HTTP/1.1 307 Temporary Redirect
< Date: Mon, 17 Jun 2019 07:11:31 GMT
< Server: Kestrel
< Content-Length: 0
< Location: https://serviceb:44359/api/bar/
<
* Curl_http_done: called premature == 0
* Connection #0 to host serviceb left intact

因此，我们可以看到serviceB告诉serviceA它的请求将被重定向到https://serviceB:44359/api/bar/，但所需的连接端口是80（容器端口），而不是44359（主机端口）

root@serviceA_id:/app# curl -v -L http://serviceb/api/bar
*   Trying 10.168.0.3...
* TCP_NODELAY set
* Connected to serviceb (10.168.0.3) port 80 (#0)
> GET /api/bar HTTP/1.1
> Host: serviceb
> User-Agent: curl/7.52.1
> Accept: */*
>
< HTTP/1.1 307 Temporary Redirect
< Date: Wed, 19 Jun 2019 08:48:33 GMT
< Server: Kestrel
< Content-Length: 0
< Location: https://serviceb:44359/api/bar
<
* Curl_http_done: called premature == 0
* Connection #0 to host serviceb left intact
* Issue another request to this URL: 'https://serviceb:44359/api/bar'
*   Trying 10.168.0.3...
* TCP_NODELAY set
* connect to 10.168.0.3 port 44359 failed: Connection refused
* Failed to connect to serviceb port 44359: Connection refused
* Closing connection 1
curl: (7) Failed to connect to serviceb port 44359: Connection refused

为什么我被重定向到主机端口？

在startup.cs中，我的服务使用app.usehttpsRedirection()；，因此删除该行解决了问题

如果我还需要使用HTTPS怎么办？添加使用容器端口的选项。答案中的更多信息

Answer 1

ServiceA的HTTP请求被重定向（HTTP 307状态代码）到https://ServiceB:44359/API/BAR是HTTPS的主机端口:44359。容器之间不能访问主机端口，而容器端口可以访问。因此，如果我访问ServiceA的终端，并发送一个带有curlverbose-v的HTTP请求，该请求遵循重定向-l到URIHTTP://serviceB/API/BAR，我会收到连接拒绝错误：

root@serviceA_id:/app# curl -v -L http://serviceb/api/bar
*   Trying 10.168.0.3...
* TCP_NODELAY set
* Connected to serviceb (10.168.0.3) port 80 (#0)
> GET /api/bar HTTP/1.1
> Host: serviceb
> User-Agent: curl/7.52.1
> Accept: */*
>
< HTTP/1.1 307 Temporary Redirect
< Date: Wed, 19 Jun 2019 08:48:33 GMT
< Server: Kestrel
< Content-Length: 0
< Location: https://serviceb:44359/api/bar
<
* Curl_http_done: called premature == 0
* Connection #0 to host serviceb left intact
* Issue another request to this URL: 'https://serviceb:44359/api/bar'
*   Trying 10.168.0.3...
* TCP_NODELAY set
* connect to 10.168.0.3 port 44359 failed: Connection refused
* Failed to connect to serviceb port 44359: Connection refused
* Closing connection 1
curl: (7) Failed to connect to serviceb port 44359: Connection refused

为什么我被重定向到主机端口？

在startup.cs中，我的服务使用了app.useHttpsRedirection()；，这一行导致了问题。

HttpspolicyBuilderExtensions.UseHttpSRedirection（IApplicationBuilder）方法的默认配置默认重定向到HTTPS主机端口。如果要使用不同的端口进行重定向，则需要添加该选项，这样startup.cs将如下所示：

public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        public void ConfigureServices(IServiceCollection services)
        {

            ...

            services.AddHttpsRedirection(options =>
            {
                options.HttpsPort = 443;
            });

            ...

        }

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {

            ...

            app.UseHttpsRedirection();

            ...

        }
    }