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

问题描述

我正在尝试将PHP应用程序码头化。在dockerfile中，我下载了存档，将其解压缩，等等。

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更新了dockerfile，则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就像我对数据库所做的那样。

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

我尝试了两种方式，分别是使用卷和直接路径。

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:

这会导致错误：

然后我尝试使用给定的路径（作为已装入的卷）进行尝试。

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

但是，两种方法都不起作用。

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

但随后失败，并显示以下内容：

But then it fails with:

/ var / www / html / config.php\导致not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创建上载文件夹，然后创建config.php文件夹。不是文件。

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

还是还有另一种方法可以持久保存配置？

Or is there another way to persist the config?

推荐答案

TL; DR /通知：

如果遇到正在创建的目录来代替要挂载的文件，则可能是失败了提供有效和绝对路径。这是一个无声且令人困惑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.

文件卷是在docker中以这种方式完成的（绝对路径示例（可以使用env变量），则需要提及文件名）：

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

您也可以执行以下操作：

You can also do:

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

如果您从 / src / docker / myapp触发docker-compose 文件夹

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