Weekly Report IX (July 23~July 29)

Weekly Report IX

Done this week

As planned last week, the process of this week is listed as follows.

1. Update the travis-ci automatic build matrix of the project. Now the build matrix is as follows.
2. Finish the pending module migration. Now all the modules have been migrated to Python 3. In addition, all of the modules have passed the test on both Python 2 and 3, see the build report on https://travis-ci.org/kbandla/dpkt/builds/72835972 for details.
3. Solve the problems and suggestions Kiran mentioned during last discussion.
4. Update the migration notes. See https://github.com/kbandla/dpkt/blob/migrate_py3/MigrationNotes.md for details.

Some technical details for last weeks are listed as follows.

Test related

The build failure problem we met last week is due to the mechanism of travis. First it will config the tox environment, then the tox will run on the virtual machine. In addition, tox will first build every module in the package and dpkt3.py cannot be interpreted on Python 3.

The solution is to update the metaclass migration approach.

Metaclass migration

Based on http://python-3-patterns-idioms-test.readthedocs.org/en/latest/Metaprogramming.html.

The equivalent of:

class C: pass

is:

C = type('C', (), {})

Thus the metaclass syntax in dpkt.py module can be modified, which is both Python 2 and 3 compatible, as follows.

class Packet(_MetaPacket("Temp", (object,), {}))

Import related

Python 3 changes the syntax for imports from within a package, requiring you to use the relative import syntax, saying from . import mymodule instead of the just import mymodule.

Kiran mentioned a problem when setup on Python 3 (See below). The relative import is the key point. After fixing the import statements, this issue has been fixed.

Traceback (most recent call last):
  File "setup.py", line 18, in <module>
    package = __import__(package_name)
  File "/home/travis/build/kbandla/dpkt/dpkt/__init__.py", line 11, in <module>
    import ah
ImportError: No module named 'ah'
ERROR: FAIL could not package project - v = InvocationError('/home/travis/virtualenv/python3.4.2/bin/python /home/travis/build/kbandla/dpkt/setup.py sdist --formats=zip --dist-dir /home/travis/build/kbandla/dpkt/.tox/dist (see /home/travis/build/kbandla/dpkt/.tox/log/tox-0.log)', 1)

General Plan

Plan for next week

1. Now the migrate_py3 branch is 9 commits behind master. I need to update the recent change to the migration branch.
2. Send a PR for the migration. Ask for code review and update the code based on the comments.
3. Continue updating the migration notes.
4. If there's extra time, I'll add some documentation to the project, which is also planned several weeks ago.