ANN: Version 0.1.2 of sarge (a subprocess wrapper library) has beenreleased.


V

Vinay Sajip

Version 0.1.2 of Sarge, a cross-platform library which wraps the subprocess
module in the standard library, has been released.

What changed?
-------------

- Fixed issue #12: Prevented a hang which occurred when a redirection failed.

- Fixed issue #11: Added "+" to the characters allowed in parameters.

- Fixed issue #10: Removed a spurious debugger breakpoint.

- Fixed issue #9: Relative pathnames in redirections are now relative to the
current working directory for the redirected process.

- Added the ability to pass objects with "fileno()" methods as values
to the "input" argument of "run()", and a "Feeder" class which
facilitates passing data to child processes dynamically over time (rather
than just an initial string, byte-string or file).

- Added functionality under Windows to use PATH, PATHEXT and the
registry to find appropriate commands. This can e.g. convert a
command 'foo bar', if 'foo.py' is a Python script in the
c:\Tools directory which is on the path, to the equivalent
'c:\Python26\Python.exe c:\Tools\foo.py bar'. This is done internally
when a command is parsed, before it is passed to subprocess.

- Fixed issue #7: Corrected handling of whitespace and redirections.

- Fixed issue #8: Added a missing import.

- Added Travis integration.

- Added encoding parameter to the "Capture" initializer.

- Fixed issue #6: addressed bugs in Capture logic so that iterating over
captures is closer to subprocess behaviour.

- Tests added to cover added functionality and reported issues.

- Numerous documentation updates.

What does Sarge do?
-------------------

Sarge tries to make interfacing with external programs from your
Python applications easier than just using subprocess alone.

Sarge offers the following features:

* A simple way to run command lines which allows a rich subset of Bash-
style shell command syntax, but parsed and run by sarge so that you
can run on Windows without cygwin (subject to having those commands
available):
...
'foo\n'
'bar\n'

* The ability to format shell commands with placeholders, such that
variables are quoted to prevent shell injection attacks.

* The ability to capture output streams without requiring you to
program your own threads. You just use a Capture object and then you
can read from it as and when you want.

* The ability to look for patterns in captured output and to interact
accordingly with the child process.

Advantages over subprocess
---------------------------

Sarge offers the following benefits compared to using subprocess:

* The API is very simple.

* It's easier to use command pipelines - using subprocess out of the
box often leads to deadlocks because pipe buffers get filled up.

* It would be nice to use Bash-style pipe syntax on Windows, but
Windows shells don't support some of the syntax which is useful, like
&&, ||, |& and so on. Sarge gives you that functionality on Windows,
without cygwin.

* Sometimes, subprocess.Popen.communicate() is not flexible enough for
one's needs - for example, when one needs to process output a line at
a time without buffering the entire output in memory.

* It's desirable to avoid shell injection problems by having the
ability to quote command arguments safely.

* subprocess allows you to let stderr be the same as stdout, but not
the other way around - and sometimes, you need to do that.

Python version and platform compatibility
-----------------------------------------

Sarge is intended to be used on any Python version >= 2.6 and is
tested on Python versions 2.6, 2.7, 3.1, 3.2 and 3.3 on Linux,
Windows, and Mac OS X (not all versions are tested on all platforms,
but sarge is expected to work correctly on all these versions on all
these platforms).

Finding out more
----------------

You can read the documentation at

http://sarge.readthedocs.org/

There's a lot more information, with examples, than I can put into
this post.

You can install Sarge using "pip install sarge" to try it out. The
project is hosted on BitBucket at

https://bitbucket.org/vinay.sajip/sarge/

And you can leave feedback on the issue tracker there.

I hope you find Sarge useful!

Regards,

Vinay Sajip
 
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