escaping - 如何在 docker compose 文件中转义 $ 美元符号？

Question

当我尝试评估我的 docker-compose.yml 文件时，我有一个 YAML 标量抛出以下错误:

ERROR: Invalid interpolation format for "environment" option in service "time_service": "${Time.now}"

YAML:

---
version: '2'
services:
  time_service:
    build: "."
    environment:
      TIME: "${Time.now}"

如何保持与写入相同的字符串输出，但避免让 docker-compose 将其解释为错误的字符串插值？

Answer 1

You can use a $$ (double-dollar sign) when your configuration needs a literal dollar sign.

您正在使用 docker-compose 变量替换，这是有详细记录的 here :

Both $VARIABLE and ${VARIABLE} syntax are supported. Extended shell-style features, such as ${VARIABLE-default} and ${VARIABLE/foo/bar}, are not supported.

You can use a $$ (double-dollar sign) when your configuration needs a literal dollar sign. This also prevents Compose from interpolating a value, so a $$ allows you to refer to environment variables that you don’t want processed by Compose.

docker-compose 是用 Python 编写的，如 github 上所示。 ，在很多程序中都可以找到获得特殊字符原始含义的加倍机制，我自己在编程时需要使用这个机制，早在 1984 年。