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我想取消设置 bash 变量列表，这些变量的变量字符串存储在数组中

tag-icon • tag-icon bash environment-variables docker
我想取消设置 bash 变量列表，这些变量的变量字符串存储在数组中

我正在创建一个 Dockerfile，它调用一个名为start.sh“我想获取从用户传递的环境变量”的脚本，docker-compose.yml或者docker run -e现在我想做的是我有这些变量的列表在数组中动态定义。

## Environment Variables
## Missing Vars off the hop SLACK_HOOK_URL
CONFIG_SETTINGS=(
  AWS_ID
  AWS_SECRET
  BUCKET_REGION
  BUCKET_NAME
  DB_USER
  DB_PASSWORD
  DB_HOSTIP
  DB_PORT
  DB_NAME
)

我只需取消设置此数组中定义的上述变量的子集。

CONFIG_SECRETS=(
  AWS_ID
  AWS_ID_STR
  AWS_SECRET
  AWS_SECRET_STR
  BUCKET_NAME
  BUCKET_NAME_STR
  DB_USER
  DB_USER_STR
  DB_PASSWORD
  DB_PASSWORD_STR
  DB_HOSTIP
  DB_HOSTIP_STR
  DB_PORT
  DB_PORT_STR
  DB_NAME
  DB_NAME_STR
)

我的问题是以下 for 循环。

## Sanitization section
for i in "${!CONFIG_SECRETS[@]}"; do
  ## Nullify environment variables that contain secrets before launching.
  # echo ${CONFIG_SECRETS[$i]}
  eval $"${CONFIG_SECRETS[$i]}"=$""
  unset $"${CONFIG_SECRETS[$i]}"
  echo \$${CONFIG_SECRETS[$i]} is now to: $"${CONFIG_SECRETS[$i]}"
done

例如，下面是我创建的一个 for 循环，用于迭代这些变量并设置它们。

for i in "${!CONFIG_SETTINGS[@]}"; do
  echo ${CONFIG_SETTINGS[$i]}"_KEY"
  ## Indirect references http://tldp.org/LDP/abs/html/ivr.html
  eval FROM_STRING=\$"${CONFIG_SETTINGS[$i]}_STR"
  eval VALUE_STRING=\$${CONFIG_SETTINGS[$i]}
  eval KEY_STRING=\$"${CONFIG_SETTINGS[$i]}_KEY"
  TO_STRING="$KEY_STRING$VALUE_STRING"
  sed -i '' "s/$FROM_STRING/$TO_STRING/g" ./config.tmpl
done

这会修改以下配置文件。

{
  "aws_id": "YOUR-AWS-ID",
  "aws_secret": "YOUR-AWS-SECRET",
  "bucket_region": "YOUR-BUCKET-REGION",
  "bucket_name": "YOUR-BUCKET-NAME",
  "db_conn": "USER:PASSWORD@tcp(localhost:3306)/DBNAME",
  "slack_hook_url": ""
}

完整的上下文脚本减去了本问题范围之外的内容。

#!/bin/bash

## Launch service will tell prism-bin what mode to run in.
LAUNCHMODE="${MODE:-$1}"

## This variable will be what can override default launch args.  I may modify this as I learn more about prism-bin
LAUNCHARGS="${CUSTOM_ARGS:-$2}"

## This is setup this way to handle any situations that might arise from the
## config being JSON and bash not being any good at JSON.
# ## Strings to replace.
AWS_ID_STR="YOUR-AWS-ID"
AWS_SECRET_STR="YOUR-AWS-SECRET"
BUCKET_REGION_STR="YOUR-BUCKET-REGION"
BUCKET_NAME_STR="YOUR-BUCKET-NAME"
DB_USER_STR="USER"
DB_PASSWORD_STR="PASSWORD"
DB_HOSTIP_STR="localhost"
DB_PORT_STR="3306"
DB_NAME_STR="DBNAME"

# Environment Variables/Defaults
## Json sucks in BASH/Shell so you need to add trailing commas intermittently.
## Just pay attention to this.  Also at some point I'll need to make a fringe
## case for handling key/values that aren't included in the default config.
AWS_ID="${AWS_ID:-potato}"
AWS_SECRET="${AWS_SECRET:-potato}"
BUCKET_REGION="${BUCKET_REGION:-potato}"
BUCKET_NAME="${BUCKET_NAME:-potato}"
DB_USER="${DB_USER:-potato}"
DB_PASSWORD="${DB_PASSWORD:-potato}"
DB_HOSTIP="${DB_HOSTIP:-potato}"
DB_PORT="${DB_PORT:-potato}"
DB_NAME="${DB_NAME:-potato}"

## Environment Variables in Array
CONFIG_SETTINGS=(
  AWS_ID
  AWS_SECRET
  BUCKET_REGION
  BUCKET_NAME
  DB_USER
  DB_PASSWORD
  DB_HOSTIP
  DB_PORT
  DB_NAME
)
CONFIG_SECRETS=(
  AWS_ID
  AWS_ID_STR
  AWS_SECRET
  AWS_SECRET_STR
  BUCKET_NAME
  BUCKET_NAME_STR
  DB_USER
  DB_USER_STR
  DB_PASSWORD
  DB_PASSWORD_STR
  DB_HOSTIP
  DB_HOSTIP_STR
  DB_PORT
  DB_PORT_STR
  DB_NAME
  DB_NAME_STR
)

## Sanitization section
# Awaiting someone smarter than me to suggest a method for this.
# https://unix.stackexchange.com/questions/474097/i-want-to-unset-a-list-of-bash-variables-that-have-their-variable-strings-stored
for i in "${CONFIG_SECRETS[@]}"; do
  unset $i
  eval echo \$"${CONFIG_SECRETS[$i]}"=\$${CONFIG_SETTINGS[$i]}
done

答案1

这应该是一个简单的循环

#!/bin/bash

UNSET=(a b c)

a=10 b=20 c=30 d=40 e=50

echo Before a=$a b=$b c=$c d=$d e=$e

for i in ${UNSET[@]}
do
  unset $i
done

echo After a=$a b=$b c=$c d=$d e=$e

这导致

Before a=10 b=20 c=30 d=40 e=50
After a= b= c= d=40 e=50

答案2

您可以使用以下方式取消引用变量!：

$ foo=bar
$ bar=1
$ echo ${!foo}
1

你不能使用变量里面不过，像这样的扩展，所以你可能不得不用 做一些非常丑陋的事情eval。

答案3

我认为你已经把自己陷入了一个圈子；只需循环数组并取消设置循环引用的参数即可：

AWS_SECRET='secret_here'
echo Before:
declare -p AWS_SECRET
set|grep AWS_SECRET

for secret in "${CONFIG_SECRETS[@]}"
do
  unset $secret
done

echo After:
declare -p AWS_SECRET
set|grep AWS_SECRET

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