[英]python pexpect print output before or after matching the output
I am using pexpect
to match the output with the expected string.我正在使用pexpect
将 output 与预期的字符串匹配。 I also want to print the output of the command to stdout.我还想将命令的 output 打印到标准输出。 I currently have this:我目前有这个:
def cliExecute(cmd):
try:
print("Running:", cmd)
cli = pexpect.spawn(cmd)
return cli
except:
print("Failed to execute command:", str(cmd), sys.exc_info()[0])
print("Stopping test due to error")
sys.exit(1)
def cliExpect(cli, expectation, timeout=30):
try:
# print(cli.read().decode()) Doing this will print o/p but the next command fails
cli.expect(expectation, timeout=timeout)
except:
raise cliExpectFail("Failed to find: ", expectation,
"\nLast exec line:" + str(cli.before))
The above logic matches the output when I use cliExpect
but I also want to log the output I am matching to.当我使用cliExpect
时,上述逻辑与 output 匹配,但我也想记录我匹配的 output。 If I add the print(cli.read().decode())
line, I will see the output but the matching fails but when I switch the expect with print, the print of output doesn't happen.如果我添加print(cli.read().decode())
行,我会看到 output 但是匹配失败但是当我用 print 切换期望时, output 的打印不会发生。 Any thoughts on how to fix this?关于如何解决这个问题的任何想法?
read
and expect/expect_exact
do different things: read
和expect/expect_exact
做不同的事情:
read
is best for forcing output, such as plots, but without a buffer size, it will read until it encounters and EOF, effectively closing the child implicitly (see pexpect.spawn.read ). read
最适合强制 output,例如绘图,但没有缓冲区大小,它将读取直到遇到 EOF,有效地隐式关闭子项(请参阅pexpect.spawn.read )。expect
reads all output after a spawn
or the last send/sendline
, for an open child process . expect
在spawn
或最后一个send/sendline
线之后读取所有 output ,用于打开的子进程。 expect
will not usually close a child, unless it reaches a timeout
(see pexpect.spawn.exact ). expect
通常不会关闭孩子,除非它达到timeout
(请参阅pexpect.spawn.exact )。Here's an example of what I mean:这是我的意思的一个例子:
NOTE - Tested on Ubuntu 20.04, using Python 3.8注意- 在 Ubuntu 20.04 上测试,使用 Python 3.8
import pexpect
# This child executes a single command and closes implicitly
cli = pexpect.spawn("ls -l")
# I use expect_exact when using symbols like $ (also used by expect's regex)
index = cli.expect_exact(["$", pexpect.EOF, ])
if index == 0:
print("First child still open, so use *before*:\n", cli.before)
cli.close()
else:
# This will happen
print("First child closed, so use *read*:\n", cli.read())
# The child stays open after this command. You should close this child explicitly
cli = pexpect.spawn("/bin/bash")
index = cli.expect_exact(["$", pexpect.EOF, ])
if index == 0:
# This will happen
cli.sendline("ls -l")
cli.expect_exact("$")
print("Next child still open, so use *before*:\n", cli.before)
cli.close()
else:
print("Next child closed, so use *read*:\n", cli.read())
Output: Output:
First child closed, so use *read*:
b''
Next child still open, so use *before*:
b'ls -l\r\ntotal 28\r\n-rw-rw-r-- 1 ***** ***** 3393 Dec 1 15:52 *****.py\r\n-rw-rw-r-- 1 ***** ***** 1071 Dec 1 21:54 cli.py\r\n-rw-rw-r-- 1 ***** ***** 793 Nov 29 19:46 *****.py\r\n-rw-rw-r-- 1 ***** ***** 796 Nov 29 19:37 *****.py\r\n-rw-rw-r-- 1 ***** ***** 1118 Nov 29 16:05 *****.py\r\n-rw-rw-r-- 1 ***** ***** 709 Nov 29 16:21 *****.py\r\n-rw-rw-r-- 1 ***** ***** 376 Nov 22 19:47 *****.log\r\n
As you can see, read
can be hit or miss.如您所见, read
可能会被击中或错过。 For in-and-out CLI commands, I recommend pexpect.run
instead:对于进出 CLI 命令,我建议改为使用pexpect.run
:
import pexpect
list_of_commands = ["ls -l", ]
for c in list_of_commands:
command_output, exitstatus = pexpect.run(c, withexitstatus=True)
if exitstatus != 0:
raise RuntimeError("Unable to {0}: {1}".format(c, command_output.strip()))
print(command_output.strip().decode())
Output: Output:
total 28
-rw-rw-r-- 1 ***** ***** 3393 Dec 1 15:52 *****.py
-rw-rw-r-- 1 ***** ***** 1071 Dec 1 21:54 cli.py
-rw-rw-r-- 1 ***** ***** 793 Nov 29 19:46 *****.py
-rw-rw-r-- 1 ***** ***** 796 Nov 29 19:37 *****.py
-rw-rw-r-- 1 ***** ***** 1118 Nov 29 16:05 *****.py
-rw-rw-r-- 1 ***** ***** 709 Nov 29 16:21 *****.py
-rw-rw-r-- 1 ***** ***** 376 Nov 22 19:47 *****.log
Good luck with your code!祝你的代码好运!
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