如何从Cron作业中访问Docker设置环境变量 [英] How can I access Docker set Environment Variables From a Cron Job

问题描述

我最近尝试从链接的Docker容器中运行一个cron作业，遇到问题。我的主docker容器链接到postgres容器，并且在容器创建时，其端口号被docker设置为一个环境变量。此环境变量未在〜/ .profile或运行我的cron作业时加载的任何其他源文件中设置。如何才能从我的cron工作中访问这些环境变量？

谢谢！

解决方案

我遇到同样的问题。我有一个运行cron的docker容器定期执行一些shell脚本。我也很难找出当我在容器内手动执行时，为什么我的脚本会运行正常。我尝试了创建一个首先运行环境的shell脚本的所有技巧，但是它们从未对我有用（很可能我做错了）。但是我继续寻找并发现了这一点，并且它的工作正常。

1. 为您的cron容器设置一个启动或入口点shell脚本


2. 使它成为执行 printenv |的第一行grep -vno_proxy>> / etc / environment

这里的诀窍是 / etc / / code>文件。当容器建成时，文件是空的，我有意思。在 cron（8）

的手册页中，我找到了对该文件的引用。 / A>。在查看cron的所有版本后，它们都会包含一个 / etc /？文件，您可以使用它们将环境变量提供给子进程。

另外，请注意，我创建了我的docker容器在前台运行cron， cron -f 。这有助于我避免使用 tail 运行以保持容器的其他技巧。

这是我的entrypoint.sh文件作为参考，我的容器是debian：jessie base image。

  printenv | grep -vno_proxy>> / etc / environment 
 
 cron -f 
  

在 docker运行命令期间设置的环境变量。

I've recently tried running a cron job from within a linked docker container and run into an issue. My main docker container is linked to a postgres container and its port number is set as an environment variable by docker upon the containers creation. This environment variable is not set in ~/.profile or any other source file that I could load when running my cron job. How can I then access these environment variables from my cron job?

Thanks!

解决方案

I ran into this same problem. I have a docker container that runs cron to execute some shell scripts periodically. I too had a hard time finding out why my scripts would run fine when I manually executed them inside the container. I tried all the tricks of creating a shell script that would run first to set the environment, but they never worked for me (most likely I did something wrong). But I continued looking and found this and it does work.

1. Setup a start or entry point shell script for your cron container
2. Make this the first line to execute printenv | grep -v "no_proxy" >> /etc/environment

The trick here is the /etc/environment file. When the container is built that file is empty, I think on purpose. I found a reference to this file in the man pages for cron(8). After looking at all the versions of cron they all elude to an /etc/? file that you can use to feed environment variables to child processes.

Also, note that I created my docker container to run cron in the foreground, cron -f. This helped me avoid other tricks with tail running to keep the container up.

Here is my entrypoint.sh file for reference and my container is a debian:jessie base image.

printenv | grep -v "no_proxy" >> /etc/environment

cron -f

Also, this trick worked even with environment variables that are set during, docker run commands.

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