PYCC

PYCC is a Python library for implementing Crypto-Conditions for the Komodo blockchain.

It's like a Django Web Framework for CC.

Concepts

In PYCC you declare a schema for a CC contract, and you get a set of functions to create and validate transactions.

PYCC apps can be plugged into the Komodo blockchain by building komodo with blockchain support (link TODO).

Schema

The Schema is where you declare the structure of your CC app. A schema contains CC apps, which define transactions.

See an example of a faucet app defined as a PYCC schema.

Consume and Produce

The Schema then gives you two functions: consume to turn a tx into params (while also validating the structure), and produce to to create a tx from params.

During the on-chain validation, the transaction is consumed in order to validate it's structure, and the business logic is performed on the resulting params rather than the TX itself.

                             Consume (also validates)

                           +-------------------------->


      +--------------------+                          +--------------------+
      |                    |                          |                    |
      |    Tx Binary       |                          |     Tx Params      |
      |                    |                          |                    |
      +--------------------+                          +--------------------+

                           <--------------------------+

                               Produce Tx from Params

Tx deconstruction

PYCC conceptualizes transactions as function calls, that have many parameters and a tuple of outputs.

The number of inputs and outputs may vary, but the structure is static. When a variable number of inputs is required, that is encoded as a list of inputs, so the structure does not change.

Setup

Install rust: https://www.rust-lang.org/tools/install

rustup toolchain install nightly

build pycctx.so

cd ~/pycc
make pycctx

create a new virtual env

virtualenv -p python3 .env

enter virtual env

source .env/bin/activate

install

pip install -r requirements_test.txt
pip install .

add ~/pycc PATH

export PYTHONPATH=:~/pycc

launch a new chain using https://github.com/alrighttt/komodo/tree/pycc with CONFIGURE_FLAGS="--enable-pycc"

./komodod -ac_name=PYCC -ac_supply=999999 -ac_nk=96,5 -ac_blocktime=10 -testnode=1 -ac_pycc=pycc.active -ac_cc=2

This chain will now redirect ALL CC validation to ~/pycc/pycc/active.py. This active.py will define which pyCC modules are activated and route validation and pycli requests accordingly.

To run tests:

pytest

dth88/pycc-1