如何在卷中挂载单个文件 [英] How to mount a single file in a volume

问题描述

我正在尝试 dockerize 一个 PHP 应用程序.在 dockerfile 中，我下载存档、解压缩等.

I am trying to dockerize a PHP application. In the dockerfile, I download the archive, extract it, etc.

一切正常.但是，如果发布了新版本并且我更新了 dockerfile，我必须重新安装该应用程序，因为 config.php 被覆盖了.

Everything works fine. However, if a new version gets released and I update the dockerfile, I have to reinstall the application, because the config.php gets overwritten.

所以我想我可以将文件挂载为一个卷，就像我对数据库所做的一样.

So I thought I can mount the file as a volume, like I do with the database.

我尝试了两种方法，一种是音量，一种是直接路径.

I tried it two ways, with a volume and a direct path.

docker-compose:

docker-compose:

version: '2'
services:
  app:
    build: src
    ports:
      - "8080:80"
    depends_on:
      - mysql
    volumes:
      -  app-conf:/var/www/html/upload
      -  app-conf:/var/www/html/config.php
    environment:
      DB_TYPE: mysql
      DB_MANAGER: MysqlManager

  mysql:
    image: mysql:5.6
    container_name: mysql
    volumes:
      - mysqldata:/var/lib/mysql
    ports:
      - 3306:3306
    environment:
      MYSQL_ROOT_PASSWORD:
      MYSQL_DATABASE:
      MYSQL_USER:
      MYSQL_PASSWORD:

volumes:
  mysqldata:
  app-conf:

导致错误的原因:

我用给定的路径尝试了它，作为一个已安装的卷.

And I tried it with a given path, as a mounted volume.

/src/docker/myapp/upload:/var/www/html/upload
/src/docker/myapp/upload:/var/www/html/config.php

然而，这两种方式都行不通.使用安装的卷，我看到上传已创建.

However, both ways are not working. With the mounted volume, I see that upload gets created.

但是它失败了:

/var/www/html/config.php"导致不是目录""

/var/www/html/config.php" caused "not a directory"""

如果我尝试使用

/src/docker/myapp/upload/config.php:/var/www/html/config.php

Docker 创建上传文件夹，然后创建一个 config.php 文件夹.不是文件.

Docker creates the upload folder and then a config.php folder. Not a file.

或者有其他方法可以持久化配置吗?

Or is there another way to persist the config?

推荐答案

TL;DR/通知:

如果您遇到一个目录被创建来代替您尝试挂载的文件，您可能没有提供有效和绝对路径.这是无声和混乱的失败模式的常见错误.

TL;DR/Notice:

If you experience a directory being created in place of the file you are trying to mount, you have probably failed to supply a valid and absolute path. This is a common mistake with a silent and confusing failure mode.

文件卷在docker中是这样做的(绝对路径示例(可以使用env变量)，需要提文件名):

File volumes are done this way in docker (absolute path example (can use env variables), and you need to mention the file name) :

    volumes:
      - /src/docker/myapp/upload:/var/www/html/upload
      - /src/docker/myapp/upload/config.php:/var/www/html/config.php

你也可以这样做:

    volumes:
      - ${PWD}/upload:/var/www/html/upload
      - ${PWD}/upload/config.php:/var/www/html/config.php

如果你从 /src/docker/myapp 文件夹启动 docker-compose

If you fire the docker-compose from /src/docker/myapp folder

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