无法在 nginx:alpine 中安装 bash

Question

我有以下 Dockerfile:

# => Build container
FROM node:14-alpine AS builder
WORKDIR /app

# split the dependecies from our source code so docker builds can cache this step
# (unless we actually change dependencies)
COPY package.json yarn.lock ./
RUN yarn install
COPY . ./
RUN yarn build

# => Run container
FROM nginx:alpine

# Nginx config
WORKDIR /usr/share/nginx/html
RUN rm -rf ./*
COPY ./nginx/nginx.conf /etc/nginx/conf.d/default.conf

# Default port exposure
EXPOSE 8080

# Copy .env file and shell script to container
COPY --from=builder /app/dist .
COPY ./env.sh .
COPY .env .

USER root

# Add bash
RUN apk update && apk add --no-cache bash

# Make our shell script executable
RUN chmod +x env.sh

# Start Nginx server
CMD ["/bin/bash", "-c", "/usr/share/nginx/html/env.sh && nginx -g \"daemon off;\""]

但是当我尝试运行它时，我在尝试添加 bash 时遇到以下错误：

------
 > [stage-1 8/9] RUN apk update && apk add --no-cache bash:
#19 0.294 fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/main/x86_64/APKINDEX.tar.gz
#19 0.358 140186175183688:error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed:ssl/statem/statem_clnt.c:1914:
#19 0.360 fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/community/x86_64/APKINDEX.tar.gz
#19 0.360 ERROR: https://dl-cdn.alpinelinux.org/alpine/v3.14/main: Permission denied
#19 0.360 WARNING: Ignoring https://dl-cdn.alpinelinux.org/alpine/v3.14/main: No such file or directory
#19 0.405 140186175183688:error:1416F086:SSL routines:tls_process_server_certificate:certificate verify failed:ssl/statem/statem_clnt.c:1914:
#19 0.407 ERROR: https://dl-cdn.alpinelinux.org/alpine/v3.14/community: Permission denied
#19 0.407 WARNING: Ignoring https://dl-cdn.alpinelinux.org/alpine/v3.14/community: No such file or directory
#19 0.408 2 errors; 42 distinct packages available
------
executor failed running [/bin/sh -c apk update && apk add --no-cache bash]: exit code: 2

我需要添加以执行此脚本：

#!/bin/bash

# Recreate config file
rm -rf ./env-config.js
touch ./env-config.js

# Add assignment 
echo "window._env_ = {" >> ./env-config.js

# Read each line in .env file
# Each line represents key=value pairs
while read -r line || [[ -n "$line" ]];
do
  # Split env variables by character `=`
  if printf '%s\n' "$line" | grep -q -e '='; then
    varname=$(printf '%s\n' "$line" | sed -e 's/=.*//')
    varvalue=$(printf '%s\n' "$line" | sed -e 's/^[^=]*=//')
  fi

  # Read value of current variable if exists as Environment variable
  value=$(printf '%s\n' "${!varname}")
  # Otherwise use value from .env file
  [[ -z $value ]] && value=${varvalue}
  
  # Append configuration property to JS file
  echo "  $varname: \"$value\"," >> ./env-config.js
done < .env

echo "}" >> ./env-config.js

根据我的阅读，添加 USER root 应该可以解决这个问题，但在这种情况下不会。

关于如何解决的任何想法？

Answer 1

你应该可以使用/bin/sh作为一个标准的谍影重重shell；此外，您应该能够避免 CMD 行中的 sh -c 包装器。

首先，使用 POSIX shell syntax. Scanning over the script, it seems like it is almost okay as-is; change the first line to #!/bin/sh, and correct the non-standard ${!varname} expansion (also see Dynamic variable names in Bash)

重写脚本

# Read value of current variable if exists as Environment variable
value=$(sh -c "echo $$varname")
# Otherwise use value from .env file
[[ -z $value ]] && value=${varvalue}

您可以尝试使用 alpine 或 busybox 具有更严格 shell 的图像进行测试，或者使用 bash 设置 POSIXLY_CORRECT 环境变量.

其次，using ENTRYPOINT and CMD together 有一个合理的标准模式。 CMD 作为参数传递给 ENTRYPOINT，因此如果 ENTRYPOINT 以 exec "$@" 结尾，它将用该命令替换自身。

#!/bin/sh
#      ^^ not bash

# Recreate config file
...
echo "window._env_ = {" >> ./env-config.js
...
echo "}" >> ./env-config.js

# Run the main container CMD
exec "$@"

现在，在您的 Docker 文件中，您不需要安装 GNU bash，因为您没有使用它，但您确实需要正确拆分 ENTRYPOINT 和 CMD.

ENTRYPOINT ["/usr/share/nginx/html/env.sh"] # must be JSON-array syntax
CMD ["nginx", "-g", "daemon off;"]          # can be either syntax

顺便说一句，cmd1 && cmd2 语法是基本的 shell 语法而不是 bash 扩展，所以你可以写 CMD ["/bin/sh", "-c", "cmd1 && cmd2"];但是，如果您编写的命令没有 JSON 数组语法，Docker 将为您插入 sh -c 包装器。您几乎不需要在 Docker 文件中写出 sh -c。

无法在 nginx:alpine 中安装 bash

Cannot install bash in nginx:alpine

bash

docker

alpine