检查特定 Linux 命令是否仍在运行的 Python 脚本

Question

我想编写一个 Python 脚本，它会每分钟检查一些预定义的进程是否仍在 Linux 机器上运行，以及它是否在崩溃时不打印时间戳。我写了一个脚本，它正是这样做的，但不幸的是，它只能在一个进程中正常工作。

这是我的代码:

import subprocess
import shlex
import time
from datetime import datetime

proc_def = "top"
grep_cmd = "pgrep -a " + proc_def
try:
    proc_run = subprocess.check_output(shlex.split(grep_cmd)).decode('utf-8')
    proc_run = proc_run.strip().split('\n')
    '''
    Creating a dictionary with key the PID of the process and value
    the command line
    '''
    proc_dict = dict(zip([i.split(' ', 1)[0] for i in proc_run],
                         [i.split(' ', 1)[1] for i in proc_run]))

    check_run = "ps -o pid= -p "

    for key, value in proc_dict.items():
        check_run_cmd = check_run + key
        try:
            # While the output of check_run_cmd isn't empty line do
            while subprocess.check_output(
                                          shlex.split(check_run_cmd)
                                          ).decode('utf-8').strip():
                # This print statement is for debugging purposes only
                print("Running")
                time.sleep(3)
        '''
        If the check_run_cmd is returning an error, it shows us the time
        and date of the crash as well as the PID and the command line
        '''
        except subprocess.CalledProcessError as e:
            print(f"PID: {key} of command: \"{value}\" stopped
                  at {datetime.now().strftime('%d-%m-%Y %T')}")
            exit(1)
# Check if the proc_def is actually running on the machine
except subprocess.CalledProcessError as e:
    print(f"The \"{proc_def}\" command isn't running on this machine")

例如，如果有两个 top 进程，它将仅向我显示有关这些进程之一的崩溃时间的信息，然后它将退出。只要有另一个进程在运行，我就想保持事件状态，只有在两个进程都被杀死时才退出。它应该在每个进程崩溃时显示信息。

它也不应仅限于两个进程，并支持使用相同的 proc_def 命令启动多个进程。

Answer 1

必须稍微改变一下逻辑，但基本上你想要一个无限循环交替检查所有进程——而不是一遍又一遍地检查同一个进程:

import subprocess
import shlex
import time
from datetime import datetime

proc_def = "top"
grep_cmd = "pgrep -a " + proc_def
try:
    proc_run = subprocess.check_output(shlex.split(grep_cmd)).decode('utf-8')
    proc_run = proc_run.strip().split('\n')
    '''
    Creating a dictionary with key the PID of the process and value
    the command line
    '''
    proc_dict = dict(zip([i.split(' ', 1)[0] for i in proc_run],
                         [i.split(' ', 1)[1] for i in proc_run]))

    check_run = "ps -o pid= -p "
    while proc_dict:
        for key, value in proc_dict.items():
            check_run_cmd = check_run + key
            try:
                # While the output of check_run_cmd isn't empty line do
                subprocess.check_output(shlex.split(check_run_cmd)).decode('utf-8').strip()
                # This print statement is for debugging purposes only
                print("Running")
                time.sleep(3)
            except subprocess.CalledProcessError as e:
                print(f"PID: {key} of command: \"{value}\" stopped at {datetime.now().strftime('%d-%m-%Y %T')}")
                del proc_dict[key]
                break
# Check if the proc_def is actually running on the machine
except subprocess.CalledProcessError as e:
    print(f"The \"{proc_def}\" command isn't running on this machine")

这在原始代码中遇到了相同的问题，即时间分辨率为 3 秒，如果在此脚本期间运行新进程，您将不会 ping 它(尽管这可能是需要的)。

第一个问题可以通过减少休眠时间来解决，具体取决于您的需要，第二个问题可以通过在 while True 中运行创建 proc_dict 的初始行来解决。