docker - Golang Docker 容器未在 Docker-Compose 中重新启动

Question

我希望能够在无法连接到 rabbitmq 时重新启动 golang docker 文件，如此处所述:(Docker Compose wait for container X before starting Y 参见:svenhornberg 的回答)。不幸的是，我的 golang 容器将退出但永远不会重新启动，我不知道为什么。

Docker 撰写:

version: '3.3'
services:
  mongo:
    image: 'mongo:3.4.1'
    container_name: 'datastore'
    ports:
      - '27017:27017'
  rabbitmq:
    restart: always
    tty: true
    image: rabbitmq:3.7-management-alpine
    hostname: "rabbit"
    ports:
      - "15672:15672" 
      - "5672:5672"
    labels:
      NAME: "rabbitmq"
    volumes:
      - ./rabbitmq-isolated.conf:/etc/rabbitmq/rabbitmq.config
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:15672"]
      interval: 3s
      timeout: 5s
      retries: 20
  api:
    restart: always
    tty: true
    container_name: 'api'
    build: '.'
    working_dir: /go/src/github.com/patientplatypus/project
    ports:
      - '8000:8000'
    volumes:
      - './:/go/src/github.com/patientplatypus/project'
      - './uploads:/uploads'
      - './scripts:/scripts'
      - './templates:/templates'
    depends_on:
      - "mongo"
      - "rabbitmq"

Docker 文件:

FROM golang:latest

WORKDIR /go/src/github.com/patientplatypus/project
COPY . .

RUN go get github.com/imroc/req
<...more go gets...>
RUN go get github.com/joho/godotenv

EXPOSE 8000

ENTRYPOINT  [ "fresh" ]

这是我的 golang 代码:

package main

import (
    "fmt"
    "log"
    "os"
    "os/exec"
    "net/http"
)

func main() {

    fmt.Println("Golang server started")
    godotenv.Load()
    fmt.Println("now doing healthcheck on rabbit")
    exec.Command("docker-compose restart api")
    os.Exit(1)
  <...>

这是我的终端输出(golang 在调用 rabbit 后从不重启):

api         | 23:23:00 app         | Golang server started
api         | 23:23:00 app         | now doing healthcheck on rabbit
rabbitmq_1  | 
rabbitmq_1  |   ##  ##
rabbitmq_1  |   ##  ##      RabbitMQ 3.7.11. Copyright (C) 2007-2019 Pivotal Software, Inc.
rabbitmq_1  |   ##########  Licensed under the MPL.  See http://www.rabbitmq.com/
rabbitmq_1  |   ######  ##
rabbitmq_1  |   ##########  Logs: <stdout>
<...more rabbit logging...>

我很困惑如何让它发挥作用。我做错了什么？

编辑:

exec.Command 未正确执行，但是 os.Exit(1)、log.Fatal 和 log。 Panic 退出容器，但容器没有重启。还是一头雾水。

Answer 1

The Docker documentation says:

A restart policy only takes effect after a container starts successfully. In this case, starting successfully means that the container is up for at least 10 seconds and Docker has started monitoring it. This prevents a container which does not start at all from going into a restart loop.

由于您显示的 Go 代码基本上立即退出，因此它永远不会满足这个最少 10 秒的规则。

您可以使用 time.After 强制 Go 等待，直到进程至少存活 10 秒。有点像:

ch := time.After(10 * time.Second)
defer (func() { fmt.Println("waiting"); <-ch; fmt.Println("waited") })()

也就是说，创建一个将在 10 秒后接收事件的 channel ，然后在 main 返回之前实际接收它(如果发生则立即接收，否则等待)。从玩https://play.golang.org/p/zGY5jFWbXyk ，一个技巧是在从 channel 接收后需要有一些可观察到的效果，否则它实际上不会等待。