Python的管道可變進logstash

Question

我試圖從python2.7調用logstash命令在conf名瓦爾，我試圖運行完整的shell命令是：

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

，這裏是我的Python代碼：

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) 

我在插入listname變量時遇到了問題，就像在代碼中創建的那樣，我也在調用logstash時遇到問題。我應該使用shell/subprocess來做到這一點，還是有更好的方法？

Answer 1

上面的代碼存在許多問題。主要問題可能是您的listname應該是一個字符串（如果test不包含字符串），並且您的第二個Popen調用的語法是錯誤的（每個參數應該是它自己的列表條目）。

另外，如果您需要使用第二個進程sudo，則還有一些額外的問題，具體取決於您是否需要添加密碼。

因此，取決於如何處理這些問題，你的代碼可能看起來像下面的選項之一：

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() 

希望這將有助於你找到一個合適的解決方案。如果沒有，請進一步說明您的問題。