来自 nginx 的错误网关使用 docker-compose 发布答案

【问题标题】：Bad Gateway from nginx published with docker-compose来自 nginx 的错误网关使用 docker-compose 发布
【发布时间】：2021-08-13 17:57:08
【问题描述】：

我正在学习 docker-compose，现在我正在尝试在我的 WSL Ubuntu 上的一个 docker-compose 脚本中设置应用程序和 nginx。
我正在测试我的端点

curl -v http://127.0.0.1/weatherforecast

但是我从 nginx 收到 502 Bad Gateway。
如果我在 docker-compose 中更改暴露给端口发布的端口，如下所示，请求会绕过 nginx 并到达我的应用程序，我会收到预期的响应。

ports:
   - 5000:8080

我的设置：
应用的 dockerfile

FROM mcr.microsoft.com/dotnet/aspnet:3.1 AS base
WORKDIR /app

ENV ASPNETCORE_URLS=http://+:8080

FROM mcr.microsoft.com/dotnet/sdk:3.1 AS build
WORKDIR /src
COPY ["WebApplication2.csproj", "."]
RUN dotnet restore "./WebApplication2.csproj"
COPY . .
WORKDIR "/src/."
RUN dotnet build "WebApplication2.csproj" -c Release -o /app/build

FROM build AS publish
RUN dotnet publish "WebApplication2.csproj" -c Release -o /app/publish

FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "WebApplication2.dll"]

nginx.conf

events {
    worker_connections 1024;
}

http {
    access_log  /var/log/nginx/access.log;

    server {
        listen 80;

        location / {
            proxy_pass http://127.0.0.1:8080/;
        }
    }
}

docker-compose.yml

version: "3.9"
services:
  web:
    depends_on:
      - nginx
    build: ./WebApplication2    
    expose:
      - "8080"
  nginx:
    image: "nginx"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf
      - ./logs:/var/log/nginx/
    ports:
      - 80:80

>docker-compose ps

       Name                      Command               State                Ports
-----------------------------------------------------------------------------------------------
composetest_nginx_1   /docker-entrypoint.sh ngin ...   Up      0.0.0.0:80->80/tcp,:::80->80/tcp
composetest_web_1     dotnet WebApplication2.dll       Up      8080/tcp

/var/log/nginx/error.log

[error] 31#31: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 172.26.0.1, server: , request: "GET /weatherforecast HTTP/1.1", upstream: "http://127.0.0.1:8080/weatherforecast", host: "127.0.0.1"

cURL 输出：

*   Trying 127.0.0.1:80...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 80 (#0)
> GET /weatherforecast HTTP/1.1
> Host: 127.0.0.1
> User-Agent: curl/7.68.0
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 502 Bad Gateway
< Server: nginx/1.21.1
< Date: Fri, 13 Aug 2021 17:50:56 GMT
< Content-Type: text/html
< Content-Length: 157
< Connection: keep-alive
<
<html>
<head><title>502 Bad Gateway</title></head>
<body>
<center><h1>502 Bad Gateway</h1></center>
<hr><center>nginx/1.21.1</center>
</body>
</html>
* Connection #0 to host 127.0.0.1 left intact

【问题讨论】：

标签： docker nginx asp.net-web-api docker-compose

【解决方案1】：

您应该将您的请求重定向到您的web 容器，而不是127.0.0.1。每个容器都作为网络的独立部分运行（每个都有不同的 IP 地址），127.0.0.1 指向本地容器。因此，在您的情况下，它指向 nginx 本身。可以使用 DNS 名称代替容器的真实 IP 地址（它等于docker-compose 中的服务名称）。使用类似的东西：

events {
    worker_connections 1024;
}

http {
    access_log  /var/log/nginx/access.log;

    server {
        listen 80;

        location / {
            proxy_pass http://web:8080/;
        }
    }
}

此外，您指定您的 web 容器依赖于 nginx，但反之亦然。喜欢：

version: "3.9"
services:
  web:
    build: .
  nginx:
    image: "nginx"
    depends_on:
      - web
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf
    ports:
      - 80:80

【讨论】：