Coding Style¶
In order to contribute code to the project, you must diligently follow the style rules describe in this chapter. Having a clean and structured code is very important for our development lifecycle, and not compliant code will most likely be rejected.
Essentially Cuckoo’s code style is based on PEP 8 - Style Guide for Python Code and PEP 257 – Docstring Conventions.
Formatting¶
Copyright header¶
All source code files must start with the following copyright header:
# Copyright (C) 2010-2013 Cuckoo Sandbox Developers.
# This file is part of Cuckoo Sandbox - http://www.cuckoosandbox.org
# See the file 'docs/LICENSE' for copying permission.
Indentation¶
The code must have a 4-spaces-tabs indentation. Since Python enforce the indentation, make sure to configure your editor properly or your code might cause malfunctioning.
Maximum Line Length¶
Limit all lines to a maximum of 79 characters.
Blank Lines¶
Separate the class definition and the top level function with one blank line. Methods definitions inside a class are separated by a single blank line:
class MyClass:
"""Doing something."""
def __init__(self):
"""Initialize"""
pass
def do_it(self, what):
"""Do it.
@param what: do what.
"""
pass
Use blank lines in functions, sparingly, to isolate logic sections. Import blocks are separated by a single blank line, import blocks are separeted from classes by one blank line.
Imports¶
Imports must be on separate lines. If you’re importing multiple objects from a package, use a single line:
from lib import a, b, c
NOT:
from lib import a
from lib import b
from lib import c
Always specify explicitly the objects to import:
from lib import a, b, c
NOT:
from lib import *
Strings¶
Strings must be delimited by double quotes (”).
Printing and Logging¶
We discourage the use of print()
: if you need to log an event please use
Python’s logging
which is already initialized by Cucoko.
In your module add:
import logging
log = logging.getLogger(__name__)
And use the log
handle, refer to Python’s documentation.
In case you really need to print a string to standard output, use the
print()
function:
print("foo")
NOT the statement:
print "foo"
Checking for keys in data structures¶
When checking for a key in a data structure use the clause “in” instead of methods like “has_key()”, for example:
if "bar" in foo:
do_something(foo["bar"])
Exceptions¶
Custom exceptions must be defined in the lib/cuckoo/common/exceptions.py file or in the local module if the exception should not be global.
Following is current Cuckoo’s exceptions chain:
.-- CuckooCriticalError
| |-- CuckooStartupError
| |-- CuckooDatabaseError
| |-- CuckooMachineError
| `-- CuckooDependencyError
|-- CuckooOperationalError
| |-- CuckooAnalysisError
| |-- CuckooProcessingError
| `-- CuckooReportError
`-- CuckooGuestError
Beware that the use of CuckooCriticalError
and its child exceptions will
cause Cuckoo to terminate.
Naming¶
Custom exceptions name must prefix with “Cuckoo” and end with “Error” if it represents an unexpected malfunction.
Exception handling¶
When catching an exception and accessing its handle, use as e
:
try:
foo()
except Exception as e:
bar()
NOT:
try:
foo()
except Exception, something:
bar()
It’s a good practice use “e” instead of “e.message”, as in the example above.
Documentation¶
All code must be documented in docstring format, see PEP 257 – Docstring Conventions. Additional comments may be added in logical blocks will be results hard to understand.
Automated testing¶
We belive in automated testing to provide high quality code and avoid dumb bugs. When possible, all code must be committed with proper unit tests. Particular attention must be placed when fixing bugs: it’s good practice to write unit tests to reproduce the bug. All unit tests and fixtures are placed in the tests folder in the cuckoo root. We adopt Nose as unit testing framework.