From d88ddb115e7bf00ee4443c6e71758c5391f69ef8 Mon Sep 17 00:00:00 2001
From: Thomas Mangin <thomas.mangin@exa.net.uk>
Date: Sat, 11 Apr 2020 00:52:20 +0100
Subject: util: T2226: passthrough for stderr, fix input, always newline
Change the code to let stderr passthrough to the screen
as it is the behaviout of os.system and subprocess.call/check_out
The input feature was not working and was fixed
Also always convert '\r\n' to '\n'
---
python/vyos/util.py | 138 +++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 105 insertions(+), 33 deletions(-)
(limited to 'python')
diff --git a/python/vyos/util.py b/python/vyos/util.py
index 291ce64ea..9ca229136 100644
--- a/python/vyos/util.py
+++ b/python/vyos/util.py
@@ -16,67 +16,137 @@
import os
import re
import sys
-from subprocess import Popen, PIPE, STDOUT, DEVNULL
+from subprocess import Popen
+from subprocess import PIPE
+from subprocess import STDOUT
+from subprocess import DEVNULL
+
def debug(flag):
- # this is to force all new flags to be registered here so that
- # they can be documented:
- # - developer: the code will drop into PBD on un-handled exception
- # - ifconfig: prints command and sysfs access on stdout for interface
+ """
+ Check is a debug flag was set by the user.
+ a flag can be set by touching the file /tmp/vyos.flag.debug
+ with flag being the flag name, the current flags are:
+ - developer: the code will drop into PBD on un-handled exception
+ - ifconfig: prints command and sysfs access on stdout for interface
+ The function returns an empty string if the flag was not set,
+ """
+
+ # this is to force all new flags to be registered here to be documented:
if flag not in ['developer', 'ifconfig']:
return ''
return flag if os.path.isfile(f'/tmp/vyos.{flag}.debug') else ''
-def debug_msg(message, section=''):
- if debug(section):
- print(f'DEBUG/{section:<6} {message}')
+def debug_msg(message, flag=''):
+ """
+ print a debug message line on stdout if debugging is enabled for the flag
+ """
+
+ if debug(flag):
+ print(f'DEBUG/{flag:<6} {message}')
+
+# There is many (too many) ways to run command with python
+# os.system, subprocess.Popen, subproces.{run,call,check_output}
+# which all have slighty different behaviour
-def popen(command, section='', shell=None, input=None, timeout=None, env=None,
- universal_newlines=None, stdout=PIPE, stderr=STDOUT, decode=None):
- """ popen does not raise, returns the output and error code of command """
+
+def popen(command, flag='', shell=None, input=None, timeout=None, env=None,
+ stdout=PIPE, stderr=None, decode=None):
+ """
+ popen is a wrapper helper aound subprocess.Popen
+ with it default setting it will return a tuple (out, err)
+ out: the output of the program run
+ err: the error code returned by the program
+
+ it can be affected by the following flags:
+ shell: do not try to auto-detect if a shell is required
+ for example if a pipe (|) or redirection (>, >>) is used
+ input: data to sent to the child process via STDIN
+ the data should be bytes but string will be converted
+ timeout: time after which the command will be considered to have failed
+ env: mapping that defines the environment variables for the new process
+ stdout: define how the output of the program should be handled
+ - PIPE (default), sends stdout to the output
+ - DEVNULL, discard the output
+ stderr: define how the output of the program should be handled
+ - None (default), send/merge the data to/with stderr
+ - PIPE, popen will append it to output
+ - STDOUT, send the data to be merged with stdout
+ - DEVNULL, discard the output
+ decode: specify the expected text encoding (utf-8, ascii, ...)
+
+ usage:
+ to get both stdout, and stderr: popen('command', stdout=PIPE, stderr=STDOUT)
+ to discard stdout and get stderr: popen('command', stdout=DEVNUL, stderr=PIPE)
+ """
+ debug_msg(f"cmd '{command}'", flag)
use_shell = shell
+ stdin = None
if shell is None:
- use_shell = True if ' ' in command else False
+ use_shell = False
+ if ' ' in command:
+ use_shell = True
+ if env:
+ use_shell = True
+ if input:
+ stdin = PIPE
+ input = input.encode() if type(input) is str else input
p = Popen(
command,
- stdout=stdout, stderr=stderr,
+ stdin=stdin, stdout=stdout, stderr=stderr,
env=env, shell=use_shell,
- universal_newlines=universal_newlines,
)
- tmp = p.communicate(input, timeout)[0].strip()
- debug_msg(f"cmd '{command}'", section)
- decoded = tmp.decode(decode) if decode else tmp.decode()
+ tmp = p.communicate(input, timeout)
+ out1 = b''
+ out2 = b''
+ if stdout == PIPE:
+ out1 = tmp[0]
+ if stderr == PIPE:
+ out2 += tmp[1]
+ decoded1 = out1.decode(decode) if decode else out1.decode()
+ decoded2 = out2.decode(decode) if decode else out2.decode()
+ decoded1 = decoded1.replace('\r\n', '\n').strip()
+ decoded2 = decoded2.replace('\r\n', '\n').strip()
+ nl = '\n' if decoded1 and decoded2 else ''
+ decoded = decoded1 + nl + decoded2
if decoded:
- debug_msg(f"returned:\n{decoded}", section)
+ debug_msg(f"returned:\n{decoded}", flag)
return decoded, p.returncode
-def run(command, section='', shell=None, input=None, timeout=None, env=None,
- universal_newlines=None, stdout=PIPE, stderr=STDOUT, decode=None):
- """ does not raise exception on error, returns error code """
+def run(command, flag='', shell=None, input=None, timeout=None, env=None,
+ stdout=DEVNULL, stderr=None, decode=None):
+ """
+ A wrapper around vyos.util.popen, which discard the stdout and
+ will return the error code of a command
+ """
_, code = popen(
- command, section,
+ command, flag,
stdout=stdout, stderr=stderr,
input=input, timeout=timeout,
env=env, shell=shell,
- universal_newlines=universal_newlines,
decode=decode,
)
return code
-def cmd(command, section='', shell=None, input=None, timeout=None, env=None,
- universal_newlines=None, stdout=PIPE, stderr=STDOUT, decode=None,
+def cmd(command, flag='', shell=None, input=None, timeout=None, env=None,
+ stdout=PIPE, stderr=None, decode=None,
raising=None, message=''):
- """ does raise exception, returns output of command """
+ """
+ A wrapper around vyos.util.popen, which returns the stdout and
+ will raise the error code of a command
+
+ raising: specify which call should be used when raising (default is OSError)
+ the class should only require a string as parameter
+ """
decoded, code = popen(
- command, section,
+ command, flag,
stdout=stdout, stderr=stderr,
input=input, timeout=timeout,
env=env, shell=shell,
- universal_newlines=universal_newlines,
decode=decode,
)
if code != 0:
@@ -92,15 +162,17 @@ def cmd(command, section='', shell=None, input=None, timeout=None, env=None,
return decoded
-def call(command, section='', shell=None, input=None, timeout=None, env=None,
- universal_newlines=None, stdout=PIPE, stderr=STDOUT, decode=None):
- """ does not raise exception on error, returns error code, print output """
+def call(command, flag='', shell=None, input=None, timeout=None, env=None,
+ stdout=PIPE, stderr=None, decode=None):
+ """
+ A wrapper around vyos.util.popen, which print the stdout and
+ will return the error code of a command
+ """
out, code = popen(
- command, section,
+ command, flag,
stdout=stdout, stderr=stderr,
input=input, timeout=timeout,
env=env, shell=shell,
- universal_newlines=universal_newlines,
decode=decode,
)
print(out)
--
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