Janus

An analyzer of code cyclomatic complexity, which only works with Python 3.

A list of supported languages:

• Python
• Golang

Installation

pip3 install git+https://github.com/usharerose/janus.git

Usage

Command Line

Usage: janus [OPTIONS] [PATHS]...

  Args:     paths (tuple): the paths of files or directories

Options:
  --help  Show this message and exit.

You can input a file as target

janus foo.py

You can input directory, and analyze the files under it recursively

janus directory/

You can also input multiple paths

janus directory/ foo.py

Python Module

>>> from janus.app import Janus
>>> app = Janus()
>>> result = app.process(('/foo.py',))
>>> print(result)
{"data": [{"file": "/foo.py", "cyclomatic_complexity": 27}]}

Theory

According to the definition of cyclomatic complexity in Wikipedia

Cyclomatic complexity is a software metric used to indicate the complexity of a program. It is a quantitative measure of the number of linearly independent paths through a program's source code. It was developed by Thomas J. McCabe, Sr. in 1976.

The library is based on the following formula

V(G) = P + 1

* P is the number of decision points in the program

Development

Support New Language

1. Add the language-specific tree-sitter as submodule

[submodule "vendor/tree-sitter-go"]
	path = vendor/tree-sitter-go
	url = https://github.com/tree-sitter/tree-sitter-go

2. Execute the script to store the multiple tree-sitter into the library for local dev

python build_tree_sitter_lang_lib.py

3. Register the mapping of language's file extension to name in the file janus/settings.py

EXTENSION_LANG_NAME_MAPPING = {
    '.py': 'python',
    '.go': 'go',
    # please add it here
}

4. Add the language-specific analyzer into the file janus/analyzer.py inherited from BaseComplexityAnalyzer. Commonly you only need to overwrite the following configurations

class FooAnalyzer(BaseComplexityAnalyzer):

    EXTENSION = '.foo'

    # refer to the value in https://github.com/tree-sitter/tree-sitter-foo/blob/master/src/grammar.json
    DECISION_TYPES = [
        'if', ...
    ]

5. Add test cases under the directory tests/