The Chaos Toolkit is implemented in Python 3. A high-level language with a long successfully story for writing great software. It’s a common choice for tooling purpose.
The language supports readability well and has a large ecosystem of libraries. It is also well-spread and easy to install. The choice to not support Python 2 is a look at Python’s present and future.
The choice for a dynamic language was also motivated because the Chaos Toolkit manipulates a lot of strings and that task is made straightforward with Python.
Although Python natively does not generate (though it can be done) standalone binaries like golang would. We do not believe this will harm the project and hope that package managers will eventually provide native installers.
Well, this project is not truly a functional piece of code but the code relies as little as possible on stateful constructions as provided by classes.
Mutable data structures are used but mostly created and returned from functions rather than modified.
Generally speaking, the project draws inspirations from certain ideas of functional paradigms but does not enforce them strictly. One notable area where the code strays away from these principles is the use of exceptions rather than returning error codes. This may change if the community expresses such an intention.