求助：AWS SSM自动化文档为何自动添加 并移除脚本单引号

在AWS SSM中粘贴自动化文档脚本时，出现部分单引号被自动移除的问题，导致脚本无法正常运行。已知制表符被转义为\t的原因，但对单引号消失的问题存在疑问。

原始输入脚本 #

schemaVersion: "2.2"
description: "Check HANA DB and stop it LINUX"
mainSteps:
- action: "aws:runShellScript"
  name: "HANA_DB_STOP"
  inputs:
    runCommand:
        - '#### errocodes'
        - '#### 0   =   SCRIPT RAN OK'
        - '#### 10  =   SCRIPT FAILED'
        - ''
        - '# stop hana db'
        - 'echo "Stopping Hana DB"'
        - 'sudo /usr/sap/hostctrl/exe/sapcontrol -nr 00 -function Stop'
        - ''
        - '# check hana db state'
        - 'echo "Checking if Hana DB is running."'
        - 'HANADBSTATUS=`sudo /usr/sap/hostctrl/exe/sapcontrol -nr 00 -function GetProcessList`'
        - 'sleep 20'
        - 'if [[ "$HANADBSTATUS" =~ "GRAY" ]]'
        - 'then'
        - '    echo "Hana DB is stopped."'
        - '    exit 0'
        - 'else'
        - 'i=1'
        - 'while [[ ! "$HANADBSTATUS" =~ "GRAY" ]] && [[ "$i" -lt 11 ]]'
        - ' do'
        - '     echo "Warning: HANA DB is running. Checking 10 times with 20 second intervalls until script aborts. This is check $i." '
        - '     sudo /usr/sap/hostctrl/exe/sapcontrol -nr 00 -function Stop'
        - '     sleep 20'
        - '     # check db state again'
        - '     HANADBSTATUS=`sudo /usr/sap/hostctrl/exe/sapcontrol -nr 00 -function GetProcessList`'
        - '     ((i++))'
        - '     if [ "$i" = 10 ]'
        - '         then'
        - '             echo "Error: retried $i-Times. Couldnt stop DB. Exiting Script."'
        - '             echo "Script aborts with Error 0"'
        - '             exit 10'
        - '     fi'
        - ' done'
        - ' if [[ "$HANADBSTATUS" =~ "GRAY" ]]'
        - '    then'
        - '        echo "Hana DB is stopped."'
        - '        exit 0'
        - ' fi'
        - 'fi'

AWS返回的修改后脚本 #

schemaVersion: '2.2'
description: Check HANA DB and stop it LINUX
mainSteps:
  - action: 'aws:runShellScript'
    name: HANA_DB_STOP
    inputs:
      runCommand:
        - '#### errocodes'
        - "#### 0\t=   SCRIPT RAN OK"
        - "#### 10\t=   SCRIPT FAILED"
        - ''
        - '# stop hana db'
        - echo "Stopping Hana DB"
        - sudo /usr/sap/hostctrl/exe/sapcontrol -nr 00 -function Stop
        - ''
        - '# check db state'
        - echo "Checking if Hana DB is running."
        - HANADBSTATUS=`sudo /usr/sap/hostctrl/exe/sapcontrol -nr 00 -function GetProcessList`
        - sleep 20
        - 'if [[ "$HANADBSTATUS" =~ "GRAY" ]]'
        - then
        - '    echo "Hana DB is stopped."'
        - '    exit 0'
        - else
        - i=1
        - 'while [[ ! "$HANADBSTATUS" =~ "GRAY" ]] && [[ "$i" -lt 11 ]]'
        - "\tdo"
        - "\t\techo \"Warning: HANA DB is running. Checking 10 times with 20 second intervalls until script aborts. This is check $i.\" "
        - "\t\tsudo /usr/sap/hostctrl/exe/sapcontrol -nr 00 -function Stop"
        - "\t\tsleep 20"
        - "\t\t# check db state again"
        - "\t\tHANADBSTATUS=`sudo /usr/sap/hostctrl/exe/sapcontrol -nr 00 -function GetProcessList`"
        - "\t\t((i++))"
        - "\t\tif [ \"$i\" = 10 ]"
        - "\t\t\tthen"
        - "\t\t\t\techo \"Error: retried $i-Times. Couldnt stop DB. Exiting Script.\""
        - "\t\t\t\techo \"Script aborts with Error 0\""
        - "\t\t\t\texit 10"
        - "\t\tfi"
        - "\tdone"
        - "\tif [[ \"$HANADBSTATUS\" =~ \"GRAY\" ]]"
        - '    then'
        - '        echo "Hana DB is stopped."'
        - '    exit 0'
        - "\tfi"
        - fi

单引号被移除的原因 #

这是AWS SSM的YAML解析器自动标准化处理导致的：

• 对于不包含shell特殊语法（如变量引用$xxx、条件判断[[ ... ]]、命令替换...等）的行，SSM认为单引号是不必要的字符串包裹，会自动移除。比如echo "Stopping Hana DB"、sudo /usr/sap/hostctrl/exe/sapcontrol -nr 00 -function Stop这类简单命令行，本身不需要单引号也能被shell正确执行，因此SSM会去除单引号。
• 对于包含shell特殊语法的行，SSM会保留单引号，避免YAML解析时破坏脚本逻辑。比如if [[ "$HANADBSTATUS" =~ "GRAY" ]]这类条件判断行，单引号的存在能确保整个条件表达式作为一个完整的字符串传递给shell执行。
• 另外，YAML格式本身允许纯字符串不用引号包裹，SSM在处理时会将带单引号的简单字符串转换为无引号的标准格式，这也是单引号被移除的原因之一。

内容的提问来源于stack exchange，提问作者Cédric Jäggi