参考

Question

我正在尝试创建一个python脚本，允许与Cadence Skill（命令行界面）的某些接口。我希望任何输出都定向到shell。我觉得这应该很简单，但我还不能让它工作。但是Popen，我在命令行上看不到任何输出，我不确定communicate()是否正确发送命令。以下是我到目前为止的情况：

import re, array
import sys
from subprocess import call
from subprocess import Popen, PIPE, STDOUT
from threading  import Thread
import os

#SET THESE VARIABLES
LibraryPath = 'path_to_library'
skillPath = 'path_to_cadence'

#Cadence Environment path
cadence_env= 'source /mscad/apps/bin/mscad_bash/cadtools --env cadence'

class cd:
    """Context manager for changing the current working directory"""
    def __init__(self, newPath):
        self.newPath = os.path.expanduser(newPath)

    def __enter__(self):
        self.savedPath = os.getcwd()
        os.chdir(self.newPath)

    def __exit__(self, etype, value, traceback):
        os.chdir(self.savedPath)

# Change to proper Cadence Directory

# Debugging Variables
etype = 0; value = 0; traceback = 0

NewPath = cd(LibraryPath)
NewPath.__enter__()

# Open Cadence Virtuoso in Shell Mode

try:
    from Queue import Queue, Empty
except ImportError:
    from queue import Queue, Empty  # python 3.x

ON_POSIX = 'posix' in sys.builtin_module_names

def enqueue_output(out, queue):
    for line in iter(out.readline, b''):
        queue.put(line)
    out.close()

p = Popen(['/bin/bash', '-i', '-c', 'cadence_env cmos12s0; virtuoso -nograph'], stdout=PIPE, bufsize=1, close_fds=ON_POSIX)
q = Queue()
t = Thread(target=enqueue_output, args=(p.stdout, q))
t.daemon = True # thread dies with the program
t.start()



# read line without blocking
try:  line = q.get_nowait() # or q.get(timeout=.1)
except Empty:
    print('no output yet')
else: # got line
    print(line)

load_command = "load(\""+skillPath+"\")"
print load_command
p.communicate(input=load_command)
print "Command Sent ..."


NewPath.__exit__(etype, value, traceback)
call(["ls -l"], shell=True)

提前感谢您的帮助。

参考

Non-blocking read on a subprocess.PIPE in python

Answer 1

我使它比我的应用程序需要的更复杂;但是我遇到的主要问题是在向程序发送命令时我遗失了\n。此外，删除stdout=PIPE允许程序的所有输出直接进入控制台。

proc = Popen(['/bin/bash', '-i', '-c', 'Command_To_Open_Program'], stdin=PIPE, stderr=STDOUT)
command = "command_to_program\n"
proc.stdin.write(command)

使用Python通过命令行与Program通信

参考

1 个答案: