Python 'subprocess' CalledProcessError: Command '[...]' returned non-zero exit status 1

Question

正在执行以下脚本...

import socket                   
import sys                          

from collections import OrderedDict
from subprocess import check_output
from threading import Thread

[...]

class IpCheck(Thread):  

    RECEIVED_PACKAGES_RE = re.compile(r'(\d+) received')

    def __init__(self, ip):                         
        Thread.__init__(self)
        self.ip = ip
        self.result = None

    def run(self):                          
        match = self.RECEIVED_PACKAGES_RE.search(
            check_output(['ping', '-q', '-c2', '-W1', self.ip])
        )

        successful_ping_count = int(match.group(1)) if match else 0

        if successful_ping_count == 0:
            self.result = 'no response'
        elif successful_ping_count == 1:
            self.result = 'alive, but 50% package loss'
        elif successful_ping_count == 2:
            self.result = check_snmp(self.ip)
        else:
            assert False

[...]

...导致错误：

CalledProcessError: Command '[ping', '-q', '-c2', '-W1', '10.81.3.80 ']' returned non-zero exit status 1

在 check_output 中添加 "stderr = STDOUT" 没有产生任何有用的反馈。

如何获取有关错误的更多信息以便进行故障排除？

Answer 1

如您的错误消息所述，ping 以非零退出状态完成。这可能意味着例如提供的 IP 地址不可访问或您传递了错误的参数。

来自 ping 手册页 (http://linux.die.net/man/8/ping)：

If ping does not receive any reply packets at all it will exit with code 1. If a packet count and deadline are both specified, and fewer than count packets are received by the time the deadline has arrived, it will also exit with code 1. On other error it exits with code 2. Otherwise it exits with code 0. This makes it possible to use the exit code to see if a host is alive or not.

你可以尝试捕捉CalledProcessError，看看它在output中包含了什么。看这里 https://docs.python.org/2/library/subprocess.html#subprocess.check_output

Answer 2

subprocess.check_output raises CalledProcessError 非零退出代码，ping returns 非零退出代码如果出现问题（例如未知域名，或网站已关闭，或网站ICMP 因某种原因被阻止，或者您的 Internet 连接已断开）。

如果要检查输出和退出代码，请使用 subprocess.Popen:

import subprocess
import sys

site = sys.argv[1]
ping_count = 4
process = subprocess.Popen(['ping', site, '-c', str(ping_count)],
                           stdout=subprocess.PIPE,
                           stderr=subprocess.STDOUT)
returncode = process.wait()
print('ping returned {0}'.format(returncode))
print(process.stdout.read())

示例：

$ python ping.py google.com         <-- ping successful
ping returned 0
PING google.com (195.64.213.27) 56(84) bytes of data.
64 bytes from cache.google.com (195.64.213.27): icmp_seq=1 ttl=57 time=59.8 ms
64 bytes from cache.google.com (195.64.213.27): icmp_seq=2 ttl=57 time=2.43 ms
64 bytes from cache.google.com (195.64.213.27): icmp_seq=3 ttl=57 time=77.0 ms
64 bytes from cache.google.com (195.64.213.27): icmp_seq=4 ttl=57 time=43.8 ms

--- google.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 2.439/45.802/77.096/27.658 ms

$ python ping.py asdasdas.com       <-- DNS resolved, but site is down
ping returned 1
PING asdasdas.com (69.172.201.208) 56(84) bytes of data.

--- asdasdas.com ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 3024ms

$ python ping.py asdasdasdasda.com  <-- DNS failed
ping returned 2
ping: unknown host asdasdasdasda.com

Python 'subprocess' CalledProcessError: Command '[...]' returned non-zero exit status 1

Python 'subprocess' CalledProcessError: Command '[...]' returned non-zero exit status 1

python

subprocess

stdout

popen