commit 76205611acb95231226bf42c4c6b20388ef3cfe7 Author: Damian Johnson <atagar@torproject.org> Date: Thu Jan 3 08:35:09 2013 -0800 system.call() support for a default The 'suppress_exc' argument is a relic from long ago when I frequently made suppression the default in arm. Stem does things better, following "Errors should never pass silently. Unless explicitly silenced." A default argument lets us do the same thing as a 'suppress_exc' boolean, but with more control. It's also more uniform with our controller. --- stem/__init__.py | 6 ++++++ stem/control.py | 11 ++--------- stem/util/system.py | 13 ++++++------- 3 files changed, 14 insertions(+), 16 deletions(-) diff --git a/stem/__init__.py b/stem/__init__.py index 2482299..5fd34ab 100644 --- a/stem/__init__.py +++ b/stem/__init__.py @@ -397,6 +397,12 @@ __all__ = [ import stem.util.enum +# Constant to indicate an undefined argument default. Usually we'd use None for +# this, but users will commonly provide None as the argument so need something +# else fairly unique... + +UNDEFINED = "<Undefined_ >" + class ControllerError(Exception): "Base error for controller communication issues." diff --git a/stem/control.py b/stem/control.py index b1525a9..d8ee940 100644 --- a/stem/control.py +++ b/stem/control.py @@ -138,12 +138,11 @@ import stem.response import stem.socket import stem.util.connection import stem.util.enum +import stem.util.tor_tools import stem.version -from stem import CircStatus - +from stem import UNDEFINED, CircStatus from stem.util import log -import stem.util.tor_tools # state changes a control socket can have @@ -177,12 +176,6 @@ EventType = stem.util.enum.UppercaseEnum( "CIRC_MINOR", ) -# Constant to indicate an undefined argument default. Usually we'd use None for -# this, but users will commonly provide None as the argument so need something -# else fairly unique... - -UNDEFINED = "<Undefined_ >" - # Configuration options that are fetched by a special key. The keys are # lowercase to make case insensitive lookups easier. diff --git a/stem/util/system.py b/stem/util/system.py index 3c3abf4..0b4427e 100644 --- a/stem/util/system.py +++ b/stem/util/system.py @@ -28,6 +28,7 @@ import time import stem.util.proc +from stem import UNDEFINED, CircStatus from stem.util import log # Mapping of commands to if they're available or not. This isn't always @@ -552,20 +553,18 @@ def expand_path(path, cwd = None): return relative_path -def call(command, suppress_exc = True): +def call(command, default = UNDEFINED): """ Issues a command in a subprocess, blocking until completion and returning the results. This is not actually ran in a shell so pipes and other shell syntax are not permitted. :param str command: command to be issued - :param bool suppress_exc: if **True** then **None** is returned on failure, - otherwise this raises the exception + :param object default: response if the query fails - :returns: **list** with the lines of output from the command, **None** in - case of failure if suppress_exc is **True** + :returns: **list** with the lines of output from the command - :raises: **OSError** if this fails and suppress_exc is **False** + :raises: **OSError** if this fails and no default was provided """ try: @@ -589,6 +588,6 @@ def call(command, suppress_exc = True): except OSError, exc: log.debug("System call (failed): %s (error: %s)" % (command, exc)) - if suppress_exc: return None + if default != UNDEFINED: return default else: raise exc