Python code metrics with pymetrics

The python tool pymetrics can be used to measure your source code complexity. You can install it with easy_install pymetrics. Here is an example (running in virtual environment devenv; source code is located in src):

user1@deby:~/devenv/trunk$ ../bin/pymetrics src/greatings\
/helloworld.py

=== File: src/greatings/helloworld.py ===
Module src/greatings/helloworld.py is missing a module doc string.
Detected at line 1

Basic Metrics for module src/greatings/helloworld.py
----------------------------------------------------
          1    maxBlockDepth
          4    numBlocks
        189    numCharacters
          1    numDocStrings
          1    numFcnDocStrings
          2    numFunctions
          7    numKeywords
         16    numLines
         73    numTokens

         50.00 %FunctionsHavingDocStrings

Functions DocString present(+) or missing(-)
--------------------------------------------
- main
+ say

McCabe Complexity Metric for file src/greatings/helloworld.py
--------------------------------------------------------------
          2    __main__
          1    main
          1    say

COCOMO 2's SLOC Metric for src/greatings/helloworld.py
-------------------------------------------------------
          8    src/greatings/helloworld.py

*** Processed 1 module in run ***

Here is a script that let you generate report for all your files in src directory:

#!/bin/sh

working_dir=/tmp/$USER/pymetrics
mkdir -p $working_dir

find src/ -name \*.py > $working_dir/files.txt
../bin/pymetrics --nosql --nocsv -f $working_dir/files.txt

Here is a guideline for understanding cyclomatic complexity number:

• 1 - 15: simple code, minimum risk, can be easily covered by tests
• 15 - 30: complicated code, consider refactoring before writing tests
• 30 - 50+: complex code, refactor now, almost impossible to write a good tests

Read more about software complexity here and here.