[tor-dev] Damian's Status Report - June 2013

[Damian Johnson]

Hi all. Without much ado here's my status report for June...

* Stem: Migrated to the Mock module

Our homemade mocking framework has served us well, but over time it
taught me one very important lesson: writing a mocking framework is
hard. On the surface it seems pretty simple: apply and revert a set of
monkey patches. But how do you monkey patch class methods? What about
alias imports like the os module? And god forbid you want to mock
python's open() function.

I'm finally taking a lesson from one of my coworkers and using a
library for this. Python has several options but the most common is
PyPI's mock module, which became part of the standard library in
Python 3.3...

  http://www.voidspace.org.uk/python/mock/
  https://gitweb.torproject.org/stem.git/commitdiff/101cf0b?hp=65846e8

========================================

* Arm: Pruning the torTools utility

Arm's torTools module was a wrapper around TorCtl that provided
caching, thread safety, and a better API. Now that we're using stem
it's obsolete, and my aim is to completely eliminate it from the
codebase. This is easier said than done however. This month I pruned
vast swaths of the module, reducing it from 2768 lines to 1020...

  before: https://gitweb.torproject.org/arm.git/blob/refs/heads/release:/src/util/torTools.py
  after: https://gitweb.torproject.org/arm.git/blob/HEAD:/src/util/torTools.py

Doing this required some expansions on stem's part. Added
functionality includes...

  * get_pid() and get_user() methods in the Controller
  * system functions for getting a process' start time and FreeBSD jail path
  * the system module's call() wasn't respecting exit codes

========================================

* Stem: Remote descriptor fetching

Throughout the month Karsten and I have been bouncing ideas back and
fourth concerning a stem API for remote descriptor fetching...

https://trac.torproject.org/projects/tor/wiki/doc/stem#RemoteDescriptorFetching
https://lists.torproject.org/pipermail/tor-dev/2013-June/004957.html

I have some s3krit ideas for improving this that will address both our
use cases even better (spoiler: future style instances). We're coming
up on a four day weekend so hopefully I'll be able to start
implementing this soon!

========================================

* Stem: Expanded FAQ with answers to common Stack Overflow questions

I took a pass over the tor related questions on Stack Overflow
(http://stackoverflow.com/questions/tagged/tor), answering fifteen
that concerned controller scripting. The vast majority of those
unfortunately were some variation of 'how do I programmatically change
my IP?' which I answered with a Stem FAQ entry...

  https://stem.torproject.org/faq.html#how-do-i-request-a-new-identity-from-tor

The only question I thought was especially interesting went along the
lines of 'How do I check the IPs of the exits I'm presently using?'. I
answered this with a FAQ entry too...

  http://stackoverflow.com/questions/9777192/how-do-i-get-the-tor-exit-node-ip-address-over-the-control-port
  https://stem.torproject.org/faq.html#how-do-i-get-information-about-my-exits

========================================

... and a handful of smaller tasks...

  * Investigated the descriptor version provided via tor's 'GETINFO
ns/*' options. Contrary to to the spec it turns out these have been v3
all along, and stem now parses them as such. (#7953)
  * Our automated Jenkins test runs caught their first instance of tor
regression. This concerned LOADCONF's behavior after merging a branch
for ticket #6752 (#9122).
  * Handful of GSoC tasks (welcome/sorry emails after acceptance was
announced, and org admin prep for the program's start)
  * Added msg_type argument to ControlMessage.from_str() (request by
meejah, #8605)
  * Investigated cache consistency issue (thanks to Ravi, #7713)
  * Fixes for ONLINE target (patch by Jeremy, #8692)
  * Minor revisions to how consensus bandwidth-weights are validated (#6872)
  * Addressed an arm issue with certain TERMs (#9064)
  * Answered some questions from Sreenatha that came up while
migrating Tor Weather to Stem
(https://lists.torproject.org/pipermail/tor-dev/2013-June/005035.html)

Cheers! -Damian