python - 在 BASH 中计算持续时间的优化方法

Question

我正在使用我在 BASH 中编写的以下函数来计算持续时间并确定持续时间是否超过 5 分钟，它返回是，否则返回否。它按预期工作，但我正在处理的文件很大(数百万行)并且需要很长时间才能完成工作。我正在寻找一些优化的方法来做到这一点。

datediff() {
d2=$(date -d "$2" +%s)
d1=$(date -d "$3" +%s)
secs=$((d1 - d2))
impacted="no"
if [ $(($secs / 300 )) -gt 0 ]
  then
  impacted="yes"
fi
printf "%s\n" "$impacted"
}

我在逐行读取输入文件的 while 循环中调用此函数。

while IFS=',' read -r line;
do
   IFS=',' read source almapear almclear <<< "$line"
   echo $line, $(datediff $source "$almapear" "$almclear")
done < "$1" | tee -a output_$1

下面是示例输入文件，其中包含源名称、警报出现时间和警报清除时间:

D00O0:SOURCE3,Mon Oct 01 16:02:35 AST 2018,Mon Oct 01 16:04:19 AST 2018
D00O0:SOURCE3,Mon Oct 08 08:53:17 AST 2018,Mon Oct 08 08:54:57 AST 2018
D00O1:SOURCE3,Mon Oct 15 09:25:14 AST 2018,Mon Oct 15 09:26:59 AST 2018
D00O1:SOURCE3,Mon Oct 15 16:56:58 AST 2018,Mon Oct 15 17:58:41 AST 2018
D00O1:SOURCE3,Mon Oct 22 08:56:48 AST 2018,Mon Oct 22 09:58:31 AST 2018
D00O1:SOURCE3,Sat Oct 06 09:17:42 AST 2018,Sat Oct 06 09:19:24 AST 2018
D00O1:SOURCE3,Sat Oct 13 09:11:05 AST 2018,Sat Oct 13 09:12:47 AST 2018
D00O1:SOURCE3,Sat Oct 20 09:51:40 AST 2018,Sat Oct 20 09:53:23 AST 2018
D00O0:SOURCE3,Sat Oct 27 09:15:32 AST 2018,Sat Oct 27 09:17:11 AST 2018
D00O0:SOURCE3,Sat Sep 29 10:05:58 AST 2018,Sat Sep 29 11:07:43 AST 2018
D00O0:SOURCE3,Sun Oct 14 08:48:57 AST 2018,Sun Oct 14 09:50:43 AST 2018
D00O0:SOURCE3,Sun Oct 14 16:04:19 AST 2018,Sun Oct 14 16:06:00 AST 2018
D00O0:SOURCE3,Sun Oct 21 06:17:34 AST 2018,Sun Oct 21 06:19:17 AST 2018
D00O0:SOURCE3,Sun Oct 21 16:15:18 AST 2018,Sun Oct 21 17:17:00 AST 2018
D00O0:SOURCE3,Sun Oct 28 09:39:09 AST 2018,Sun Oct 28 09:40:47 AST 2018

下面是所需的输出:

D00O0:SOURCE3,Mon Oct 01 16:02:35 AST 2018,Mon Oct 01 16:04:19 AST 2018,no
D00O0:SOURCE3,Mon Oct 08 08:53:17 AST 2018,Mon Oct 08 08:54:57 AST 2018,no
D00O1:SOURCE3,Mon Oct 15 09:25:14 AST 2018,Mon Oct 15 09:26:59 AST 2018,no
D00O1:SOURCE3,Mon Oct 15 16:56:58 AST 2018,Mon Oct 15 17:58:41 AST 2018,yes
D00O1:SOURCE3,Mon Oct 22 08:56:48 AST 2018,Mon Oct 22 09:58:31 AST 2018,yes
D00O1:SOURCE3,Sat Oct 06 09:17:42 AST 2018,Sat Oct 06 09:19:24 AST 2018,no
D00O1:SOURCE3,Sat Oct 13 09:11:05 AST 2018,Sat Oct 13 09:12:47 AST 2018,no
D00O1:SOURCE3,Sat Oct 20 09:51:40 AST 2018,Sat Oct 20 09:53:23 AST 2018,no
D00O0:SOURCE3,Sat Oct 27 09:15:32 AST 2018,Sat Oct 27 09:17:11 AST 2018,no
D00O0:SOURCE3,Sat Sep 29 10:05:58 AST 2018,Sat Sep 29 11:07:43 AST 2018,yes
D00O0:SOURCE3,Sun Oct 14 08:48:57 AST 2018,Sun Oct 14 09:50:43 AST 2018,yes
D00O0:SOURCE3,Sun Oct 14 16:04:19 AST 2018,Sun Oct 14 16:06:00 AST 2018,no
D00O0:SOURCE3,Sun Oct 21 06:17:34 AST 2018,Sun Oct 21 06:19:17 AST 2018,no
D00O0:SOURCE3,Sun Oct 21 16:15:18 AST 2018,Sun Oct 21 17:17:00 AST 2018,yes
D00O0:SOURCE3,Sun Oct 28 09:39:09 AST 2018,Sun Oct 28 09:40:47 AST 2018,no

Answer 1

使用 GNU awk 的时间函数，这将比您的 shell 循环快几个数量级:

$ cat tst.awk
BEGIN {
    FS = "[, :]"
    OFS = ","

    split("Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec",tmp)
    for (i in tmp) {
        mth[tmp[i]] = i
    }
    maxSecs = 5 * 60
}
{
    begSecs = mktime($10" "mth[$4]" "$5" "$6" "$7" "$8)
    endSecs = mktime($18" "mth[$12]" "$13" "$14" "$15" "$16)
    print $0, ( (endSecs - begSecs) > maxSecs ? "yes" : "no" )
}

$ awk -f tst.awk file
D00O0:SOURCE3,Mon Oct 01 16:02:35 AST 2018,Mon Oct 01 16:04:19 AST 2018,no
D00O0:SOURCE3,Mon Oct 08 08:53:17 AST 2018,Mon Oct 08 08:54:57 AST 2018,no
D00O1:SOURCE3,Mon Oct 15 09:25:14 AST 2018,Mon Oct 15 09:26:59 AST 2018,no
D00O1:SOURCE3,Mon Oct 15 16:56:58 AST 2018,Mon Oct 15 17:58:41 AST 2018,yes
D00O1:SOURCE3,Mon Oct 22 08:56:48 AST 2018,Mon Oct 22 09:58:31 AST 2018,yes
D00O1:SOURCE3,Sat Oct 06 09:17:42 AST 2018,Sat Oct 06 09:19:24 AST 2018,no
D00O1:SOURCE3,Sat Oct 13 09:11:05 AST 2018,Sat Oct 13 09:12:47 AST 2018,no
D00O1:SOURCE3,Sat Oct 20 09:51:40 AST 2018,Sat Oct 20 09:53:23 AST 2018,no
D00O0:SOURCE3,Sat Oct 27 09:15:32 AST 2018,Sat Oct 27 09:17:11 AST 2018,no
D00O0:SOURCE3,Sat Sep 29 10:05:58 AST 2018,Sat Sep 29 11:07:43 AST 2018,yes
D00O0:SOURCE3,Sun Oct 14 08:48:57 AST 2018,Sun Oct 14 09:50:43 AST 2018,yes
D00O0:SOURCE3,Sun Oct 14 16:04:19 AST 2018,Sun Oct 14 16:06:00 AST 2018,no
D00O0:SOURCE3,Sun Oct 21 06:17:34 AST 2018,Sun Oct 21 06:19:17 AST 2018,no
D00O0:SOURCE3,Sun Oct 21 16:15:18 AST 2018,Sun Oct 21 17:17:00 AST 2018,yes
D00O0:SOURCE3,Sun Oct 28 09:39:09 AST 2018,Sun Oct 28 09:40:47 AST 2018,no

查看手册页以查看它使用的时区与输入文件中指定的时区，以及如何在必要时进行调整。