near-py-tool 0.1.27

Python NEAR contract build/deploy tool

Minimal build/deploy tool for Python NEAR smart contracts

This is a work-in-progress build/deploy tool for Python NEAR smart contracts.

Python source files are compiled into the WASM binary via MicroPython and Emscripten and then deployed via near-cli-rs tool.

near-py-tool CLI is modelled after cargo-near with most of the command-line options compatible (not all are implemented yet).

Dependencies

near-py-tool expects the following dependencies installed:

• Python>=3.9
• essential build tools like make and C compiler
• Emscripten for compiling Python into WASM via MicroPython (can be installed automatically by near-py-tool, if desired). Version 4.0.0 or above is recommended as there are issues with building some contracts on 3.x
• near-cli-rs for NEAR Protocol interactions

Platform support

Currenly Linux, MacOS and Windows (native/MSYS2/WSL) platforms are supported

Python library support

Most of the MicroPython standard library is included and should be functional where applicable to WASM runtime environment.

External Python package are supported as long as they don't require native compiled code to work. near-py-tool will download any packages referenced via pyproject.toml and will try to compile them into the WASM binary alongside the main contract.py file.

Unneeded modules from the MicroPython stdlib can be excluded from the build by adding the following section to pyproject.toml: [tool.near-py-tool] exclude-micropython-stdlib-packages = [...]

NEAR ABI support

Everything from https://github.com/near/near-sdk-rs/blob/master/near-sys/src/lib.rs should be available via near module, for example:

• near.input() retrieves contract input as bytes
• near.value_return(value) returns a value (str or bytes) from the contract
• near.log_utf8(message) logs a message (str)

Contract methods to be exported from the WASM binary should be decorated with @near.export

See the NEAR-ABI.md for a complete list of available methods and their type signatures.

Benchmarks

See GAS-PROFILE-REPORT.md for gas statistics from the test runs

Stats for similar Rust/JS contracts are available here

Getting started

• install near-py-tool via pip install near-py-tool
• run near-py-tool new test-project to create a minimal Python smart contract project
• cd ./test-project
• run near-py-tool build to produce a standalone WASM file
• run near-py-tool create-dev-account to create a testnet account if you don't have one already
• run near-py-tool deploy to deploy the smart contract

Examples

While there is still plenty of work ahead of us, there are already some small yet useful apps implemented using this project:

• The smart contract that guards 3000 NEAR and gives away 2 NEAR per user and prevents double-spend: https://github.com/frol/1t-agents-fundme-agent
• The smart contract that guards 50 NEAR until it is jailbreaked: https://github.com/frol/neardevnewsletter-issue50-quest/tree/main/contract
• Demo Web4 contract in Python: https://github.com/frol/near-web4-demo-py

TODO

• NEAR ABI metadata generation
• porting of a few popular/useful contracts from Rust to Python