如何在每个“exec"处执行 Docker 映像的入口点命令? [英] How to execute the Entrypoint of a Docker images at each "exec" command?

问题描述

在尝试使用 Dockerspec 测试 Dockerfiles 后，我终于遇到了一个问题我可以'无法正确解决.

After trying to test Dockerfiles with Dockerspec, I finally had an issue I can't resolve properly.

我认为问题出在 Docker 本身；如果我了解它的过程，Entrypoint 仅在运行时执行，但如果容器保持启动状态并且我在其中启动exec"命令，则不会重新调用它.

The problem is, I think, from Docker itself ; If I understand its process, an Entrypoint is only executed at run, but if the container stay started and I launch an "exec" command in, it's not re-called.

我认为这是想要的行为.

I think it's the wanted behavior.

但如果入口点是我所有命令之前的gosu"脚本，这是个问题……

But if the Entrypoint is a "gosu" script which precede all my commands, it's a problem...

示例

"myImage" 有这个入口点:gosu 1000:1000 "$@"

"myImage" has this Entrypoint : gosu 1000:1000 "$@"

如果我启动:docker run -it myImage id -u

输出为1000".

如果我启动一个容器:docker run -it myImage bash

在这个容器中，id -u 输出1000".

In this container, id -u outputs "1000".

但是如果我在这个容器中启动一个新命令，它会启动一个新的shell，并且不执行入口点，所以:docker exec CONTAINER_ID id -u

But if I start a new command in this container, it starts a new shell, and does not execute the Entrypoint, so : docker exec CONTAINER_ID id -u

输出0"，因为新的 shell 是以root"启动的.

每次入口点都有执行的方法吗?还是重新用shell打开?

It there a way to execute each time the entrypoint ? Or re-use the shell open ?

或者更好的方法?

或者，也许我什么都不懂?;)

Or, maybe I haven't understand anything ? ;)

谢谢！

编辑

在阅读了这里提出的解决方案后，我明白问题不在于 Docker 的工作方式，而在于 Serverspec 的工作方式；我的目标是直接将命令作为 docker run 参数进行测试，但 Serverspec 启动容器并使用 docker exec 测试命令.

After reading solutions proposed here, I understand that the problem is not how Docker works but how Serverspec works with ; my goal is to directly test a command as a docker run argument, but Serverspec start a container and test commands with docker exec.

因此，最好的解决方案是找到如何获取由 Serverspec 执行的 docker run 的标准输出.

So, the best solution is to found how get the stdout of the docker run executed by Serverspec.

但是，在我个人的用例中，最好的解决方案可能是不使用 Gosu，而是使用 --user 标志 :)

But, in my personal use-case, the best solution is maybe to not use Gosu but --user flag :)

推荐答案

如果您的目标是在容器内以特定用户运行 docker exec，则可以使用 --user 选项.

if your goal is to run the docker exec with a specific user inside of the container, you can use the --user option.

docker exec --user myuser container-name [...你的命令]

如果你想每次都运行 gosu，你可以用 docker exec

If you want to run gosu every time, you can specify that as the command with docker exec

docker exec container-name gosu 1000:1000 [你的实际命令]

根据我的经验，将其封装成易于重复使用的最佳方法是使用 .sh 脚本(或 Windows 中的 .cmd 文件).

in my experience, the best way to encapsulate this into something easily re-usable is with a .sh script (or .cmd file in windows).

将其放入本地文件夹中的文件中...例如 gs.

drop this into a file in your local folder... maybe gs for example.

#! /bin/sh
docker exec container-name gosu 1000:1000 "$@"

使用 chmod +x gs 授予它执行权限，然后使用本地文件夹中的 ./gs 运行它

give it execute permissions with chmod +x gs and then run it with ./gs from the local folder

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