如何在python中检索流程开始时间（或正常运行时间）

Question

如何在Linux中的python中检索进程的开始时间（或正常运行时间）？

我只知道，我可以调用“ ps -p my_process_id -f”，然后解析输出。但这并不酷。

Answer 1

如果您正在尝试测量的python程序中执行此操作，则可以执行以下操作：

import time
# at the beginning of the script
startTime = time.time()
# ...
def getUptime():
    """
    Returns the number of seconds since the program started.
    """
    # do return startTime if you just want the process start time
    return time.time() - startTime

否则，您别无选择，只能解析ps或进入/proc/pid。bash获取经过时间的一种不错的方法是：

ps -eo pid,etime | grep $YOUR_PID | awk '{print $2}'

这只会以以下格式打印经过的时间，因此它应该很容易解析：

days-HH:MM:SS

（如果运行了不到一天，那就只是HH:MM:SS）

开始时间如下所示：

ps -eo pid,stime | grep $YOUR_PID | awk '{print $2}'

不幸的是，如果您的过程不是 今天 开始的，那么只会给您开始的日期，而不是时间。

最好的方法是获取经过时间和当前时间，然后进行一些数学运算。以下是一个Python脚本，该脚本将PID作为参数，并为您执行上述操作，并打印出该过程的开始日期和时间：

import sys
import datetime
import time
import subprocess

# call like this: python startTime.py $PID

pid = sys.argv[1]
proc = subprocess.Popen(['ps','-eo','pid,etime'], stdout=subprocess.PIPE)
# get data from stdout
proc.wait()
results = proc.stdout.readlines()
# parse data (should only be one)
for result in results:
    try:
        result.strip()
        if result.split()[0] == pid:
            pidInfo = result.split()[1]
            # stop after the first one we find
            break
    except IndexError:
        pass # ignore it
else:
    # didn't find one
    print "Process PID", pid, "doesn't seem to exist!"
    sys.exit(0)
pidInfo = [result.split()[1] for result in results
           if result.split()[0] == pid][0]
pidInfo = pidInfo.partition("-")
if pidInfo[1] == '-':
    # there is a day
    days = int(pidInfo[0])
    rest = pidInfo[2].split(":")
    hours = int(rest[0])
    minutes = int(rest[1])
    seconds = int(rest[2])
else:
    days = 0
    rest = pidInfo[0].split(":")
    if len(rest) == 3:
        hours = int(rest[0])
        minutes = int(rest[1])
        seconds = int(rest[2])
    elif len(rest) == 2:
        hours = 0
        minutes = int(rest[0])
        seconds = int(rest[1])
    else:
        hours = 0
        minutes = 0
        seconds = int(rest[0])

# get the start time
secondsSinceStart = days*24*3600 + hours*3600 + minutes*60 + seconds
# unix time (in seconds) of start
startTime = time.time() - secondsSinceStart
# final result
print "Process started on",
print datetime.datetime.fromtimestamp(startTime).strftime("%a %b %d at %I:%M:%S %p")