正则表达式用于检查代码块内的行

时间：2016-05-31 22:55:23

标签： regex

我有一个haproxy服务启动脚本，如下所示：

case "$1" in
    start)
        echo -n "Starting haproxy "
        ## Start daemon with startproc(8). If this fails
        ## the return value is set appropriately by startproc.
        haproxy_check
        /sbin/startproc $HAPROXY_BIN -D -f $HAPROXY_CONF -p $HAPROXY_PID
        # Remember status and be verbose
        rc_status -v
        ;;
    stop)
        echo -n "Shutting down haproxy "
        ## Stop daemon with killproc(8) and if this fails
        ## killproc sets the return value according to LSB.

        /sbin/killproc -TERM $HAPROXY_BIN

        # this is additional forcing kill command to ensure that all processes are stopped.
        /usr/bin/killall -9 $HAPROXY_BIN || true
        # Remember status and be verbose
        rc_status -v
        ;;
    try-restart|condrestart)
        ## Do a restart only if the service was active before.
        ## Note: try-restart is now part of LSB (as of 1.9).
        ## RH has a similar command named condrestart.
        if test "$1" = "condrestart"; then
                echo "${attn} Use try-restart ${done}(LSB)${attn} rather than condrestart ${warn}(RH)${norm}"
        fi
        $0 status
        if test $? = 0; then
                # we us reload here for a graceful restart during update
                $0 reload
        else
                rc_reset        # Not running is not a failure.
        fi
        # Remember status and be quiet
        rc_status
        ;;
    restart)
        ## Stop the service and regardless of whether it was
        ## running or not, start it again.
        $0 stop
        $0 start
        haproxy_check
        # Remember status and be quiet
        rc_status
        ;;
    check)
        ## Stop the service and regardless of whether it was
        ## running or not, start it again.
        echo -n "Checking config of haproxy "
        haproxy_check
        rc_status -v
        ;;
    reload|force-reload)
        ## Like force-reload, but if daemon does not support
        ## signaling, do nothing (!)

        haproxy_check
        # If it supports signaling:
        echo -n "Reload service haproxy "
        $HAPROXY_BIN -p $HAPROXY_PID -D -f $HAPROXY_CONF -sf $(cat $HAPROXY_PID)
        rc_status -v
        ;;
    status)
        echo -n "Checking for service haproxy "
        ## Check status with checkproc(8), if process is running
        ## checkproc will return with exit status 0.

        # Return value is slightly different for the status command:
        # 0 - service up and running
        # 1 - service dead, but /var/run/  pid  file exists
        # 2 - service dead, but /var/lock/ lock file exists
        # 3 - service not running (unused)
        # 4 - service status unknown :-(
        # 5--199 reserved (5--99 LSB, 100--149 distro, 150--199 appl.)

        # NOTE: checkproc returns LSB compliant status values.
        /sbin/checkproc $HAPROXY_BIN
        # NOTE: rc_status knows that we called this init script with
        # "status" option and adapts its messages accordingly.
        rc_status -v
        ;;
    probe)
        ## Optional: Probe for the necessity of a reload, print out the
        ## argument to this init script which is required for a reload.
        ## Note: probe is not (yet) part of LSB (as of 1.9)

        test $HAPROXY_CONF -nt $HAPROXY_PID && echo reload
        ;;
    *)
        echo "Usage: $0 {start|stop|status|try-restart|restart|force-reload|reload|probe}"
        exit 1
        ;;
esac

我需要2个只能匹配haproxy_check行的正则表达式 1）start)和 2）restart)代码块。

我尝试了各种各样的事情，例如：

^\s*start\)(?:(?:(?:#|[ \t]+)[^\n]*|)\n)*?^\s*haproxy_check

上述内容匹配正常，但如果haproxy_check被注释掉，则会出错。

有什么建议吗？

谢谢和问候， Pravin Goyal

2 个答案:

答案 0 :(得分：1)

描述

特别提示：

我已经采取创造性自由在haproxy_check子字符串中包含序列号，这有助于说明我们正在捕获所需的实例。要删除此行为，只需删除_[0-9]构造。这两个表达式之间的唯一区别是前几个字符是我指定start或restart。

表达式 

\n\s*start\)(?:(?:(?![#"]|;;).)|\#[^\n]*\n|"[^"]*?")*?\K(haproxy_check_[0-9]+)

Regular expression visualization 

\n\s*restart\)(?:(?:(?![#"]|;;).)|\#[^\n]*\n|"[^"]*?")*?\K(haproxy_check_[0-9]+)

Regular expression visualization

此正则表达式将执行以下操作：

  • 分别在haproxy_check或start)块中找到restart)子字符串并将其放入捕获组0.它也包含在捕获组1中，以便突出显示在现场演示。删除haproxy_check
    • 周围的括号可以删除此行为
  • 仅从开始捕获haproxy_check或直接重启块，不要意外从尾随代码块中提取值。
  • 将跳过已注释掉的行
  • 忽略#
    • 后面的评论
  • 当包含在双引号块
    • 中时忽略haproxy_check

实施例

现场演示

https://regex101.com/r/yU3lK9/1

示例文字

我已经简化了示例文本，包括我们正在寻找的内容以及我们不寻找的内容示例。如上所述，为了便于说明，我添加了_和数字来序列化每个haproxy_check 

case "$1" in
    start)
        # haproxy_check_01 ;;
        haproxy_check_02
        # haproxy_check_03 
        rc_status -v # haproxy_check_04
        echo " haproxy_check_05 "
        ;;
    stop)
        # haproxy_check_11
        haproxy_check_12
        # haproxy_check_13
        rc_status -v # haproxy_check_14
        echo " haproxy_check_15 "
        ;;
    try-restart|condrestart)
        # haproxy_check_21
        haproxy_check_22
        # haproxy_check_23
        rc_status -v # haproxy_check_24
        echo " haproxy_check_25 "
        ;;
    restart)
        # haproxy_check_31
        haproxy_check_32
        # haproxy_check_33
        rc_status -v # haproxy_check_34
        echo " haproxy_check_35 "
        ;;
    check)
        # haproxy_check_41
        haproxy_check_42
        # haproxy_check_43
        rc_status -v # haproxy_check_44
        echo " haproxy_check_45 "
        ;;
    reload|force-reload)
        # haproxy_check_51
        haproxy_check_52
        # haproxy_check_53
        rc_status -v # haproxy_check_54
        echo " haproxy_check_55 "
        ;;
    status)
        # haproxy_check_61
        haproxy_check_62
        # haproxy_check_63
        rc_status -v # haproxy_check_64
        echo " haproxy_check_65 "
        ;;
    probe)
        # haproxy_check_71
        haproxy_check_72
        # haproxy_check_73
        rc_status -v # haproxy_check_74
        echo " haproxy_check_75 "
        ;;
    *)
        # haproxy_check_81
        haproxy_check_82
        # haproxy_check_83
        rc_status -v # haproxy_check_84
        echo " haproxy_check_85 "
        ;;
    esac

样本匹配 

MATCH for the Start Block
1.  [56-72] `haproxy_check_02`

MATCH for the Restart block
1.  [563-579]   `haproxy_check_32`

解释

NODE                     EXPLANATION
----------------------------------------------------------------------
  \n                       '\n' (newline)
----------------------------------------------------------------------
  \s*                      whitespace (\n, \r, \t, \f, and " ") (0 or
                           more times (matching the most amount
                           possible))
----------------------------------------------------------------------
  start                    'start'
----------------------------------------------------------------------
  \)                       ')'
----------------------------------------------------------------------
  (?:                      group, but do not capture (0 or more times
                           (matching the least amount possible)):
----------------------------------------------------------------------
    (?:                      group, but do not capture:
----------------------------------------------------------------------
      (?!                      look ahead to see if there is not:
----------------------------------------------------------------------
        [#"]                     any character of: '#', '"'
----------------------------------------------------------------------
       |                        OR
----------------------------------------------------------------------
        ;;                       ';;'
----------------------------------------------------------------------
      )                        end of look-ahead
----------------------------------------------------------------------
      .                        any character except \n
----------------------------------------------------------------------
    )                        end of grouping
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    \#                       '#'
----------------------------------------------------------------------
    [^\n]*                   any character except: '\n' (newline) (0
                             or more times (matching the most amount
                             possible))
----------------------------------------------------------------------
    \n                       '\n' (newline)
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    "                        '"'
----------------------------------------------------------------------
    [^"]*?                   any character except: '"' (0 or more
                             times (matching the least amount
                             possible))
----------------------------------------------------------------------
    "                        '"'
----------------------------------------------------------------------
  )*?                      end of grouping
----------------------------------------------------------------------
  \K                       'K'
----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    haproxy_check_           'haproxy_check_'
----------------------------------------------------------------------
    [0-9]+                   any character of: '0' to '9' (1 or more
                             times (matching the most amount
                             possible))
----------------------------------------------------------------------
  )                        end of \1
----------------------------------------------------------------------

答案 1 :(得分：0)

这个正则表达式（你可以看到它here）：

/^\s+(?:re)?start.*?(haproxy_check).*?;;/gsm

会做的工作。

确保：

  • 字符串以空格开头，后跟start或restart
  • 由于.*?
    • 的懒惰，它只抓住了一个街区
  • 该块包含haproxy_check（已注释或不）
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