Question

我正在尝试使用conf名称中的vars从python2.7调用logstash命令，我尝试运行的完整shell命令是：

cat test.txt | sudo /usr/share/logstash/bin/logstash -f test.conf

这是我的Python代码：

listname = test
b = '/tmp/%s.txt' % (listname)
c = '/tmp/%s.conf' % (listname)
first = subprocess.Popen(['/bin/echo', b], stdout=subprocess.PIPE)
Second = subprocess.Popen(['/usr/share/logstash/bin/logstash -f', c], stdin=first.stdout)

我无法插入先前在代码中创建的listname变量，我也无法调用logstash。我应该使用shell /子进程来执行此操作还是有更好的方法？

Answer 1

上面的代码存在许多问题。主要问题可能是您的listname应该是一个字符串（如果test不包含字符串），并且您的第二个Popen调用的语法错误（每个参数应该是它自己的列表条目。）

此外，如果您需要第二个进程使用sudo，则会出现一些额外问题，具体取决于您是否需要添加密码。

因此，根据如何处理这些问题，您的代码可能看起来像下面的替代方案之一：

from subprocess import Popen, PIPE

listname = 'test'
b = '/tmp/{}.txt'.format(listname)
c = '/tmp/{}.conf'.format(listname)

first = Popen(['/bin/cat', b], stdout=PIPE)

# Alt 1, No sudo
second = Popen(['/usr/share/logstash/bin/logstash', '-f', c], stdin=first.stdout)

# Alt 2, sudo with no password
second = Popen(['sudo', '/usr/share/logstash/bin/logstash', '-f', c], stdin=first.stdout)

# Alt 3, add sudo password (most complex)

# Alt 3.1, store password in file (bad)
sudo_password = "clear_text_password"

#Alt 3.2, ask user for password:
from getpass import getpass, getuser
sudo_password = getpass("[sudo] password for {}: ".format(getuser()))

# Since we need to add password at stdin, we cannot directly pipe output from "first"
# instead we set stdin to PIPE, and write sudo password, followed by output from "first"
# sudo -kSp '' ensures that password is read from stdin without prompt being displayed
second = Popen(['sudo', '-kSp', '', '/usr/share/logstash/bin/logstash', '-f', c], stdin=PIPE)

second.stdin.write(sudo_password + '\n') # write password

# followed by output from "first".
for line in first.stdout:
    second.stdin.write(line)

second.stdin.close()

希望这有助于您找到合适的解决方案。如果没有，请进一步说明您的问题。

Python将变量传递给logstash

1 个答案: