Title Text
Writing Ewasm in Rust
用 Rust 编写Ewasm 合约
Antonio Yang
yanganto@github
Ewasm Contract
WHAT, HOW & WHY ?
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What
Ewasm = Ethereum WebAssembly
WebAssembly is an open standard that defines a portable binary-code format for executable programs, and a corresponding textual assembly language.
Ethereum is a decentralized, open-source blockchain with smart contract (web3) functionality.
How
- A deterministic subset of WebAssembly.
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Why
Any language with HTTP protocol
Web2 Server
API
EVM
Web3 Blockchain
Restricted
Any language compile to EWasm format
WebAssembly
WHY RUST ?
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What is Rust ?
Rust is a multi-paradigm, high-level, general-purpose programming language designed for performance and safety, especially safe concurrency.
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Why Rust ?
- low-level control and reliable performance.
- free from the non-deterministic garbage collection
- no runtime, enabling small binary sizes
Web 3
BLOCKCHAIN
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Web ?
Web3 Blockchain
Talk to contract in Binary over the blockchain network
Web2 Server
API
Talk to API in Hyper Text Markup Language over the internet
API
API
API
API
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Web 3
Web
Blockchain (Web3)
Handler(s)
Main entry
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Routing
In web2, Uniform Resource Identifier(URI) for routing
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Routing
In web3, functional signature for routing
- 4 bytes
- Optional attribute
- Hash(fn_name(type,))
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Same Backend Idea
Handlers
Main function
(entry point)
Prior Art
CONTRACT IN RUST
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Contract in Rust
ewasm-rust-api
-
Version 0.11.0
-
2019 Nov 27
.rs
Executor
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ewasm-rust-api
ERC20 in Rust
but ... not really
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Pain Point
- Not really Rusty API
-
Result
-
Option
-
- Operating in low-level
-
operate on Bytes32
- Manually handle functional signature
-
- Not easy to test with cargo test
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C vs Rust
pub enum CallResult { Successful, Failure, Revert, Unknown, }
pub enum CallError { Failure, Revert, Unknown, }
fn call() -> CallResult;
fn call() -> Result<(), CallError>;
Please read things behind the wordings!
Current Status
DIFFERENT FROM WEB
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Different in Functions
Constructor
Handlers
Main function
(entry point)
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Constructor
- Another wasm executable
- Run once
- Return main wasm executable
- Not storage on chain
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Different in Storage
- File server
- Key value database
- Relational database
- Bytes 32
- ?
- ?
Web
Blockchain (Web3)
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Different in Test
- Local server
- Hot reload
- Mock request
- Free to request
- Fuzz test
- Deploy on test net
- ?
- ?
- Request with fee?
- ?
Web
Blockchain (Web3)
Writing Ewasm In Rust
SEW UP EWASM
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Sew Up
ewasm-rust-api
sewup
.rs
Web3 Blockchain
- Rusty API
- high-level operation (kv, rdb, ...)
- cargo test in local
- cargo sewup to build & deploy
- Low-level operation
- Byte32 operation
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Sew Up
Tests
Create WasmEdge runtime,
Add _compile_constructor_test,
Add _compile_runtime_test
Run each test in runtime
Use macro to add common test utilities,
then just cargo test
SewUp
HAPPY HACKING
THANK YOU
QUESTIONS?
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扫码关注
开源社公众号
Let's meet on github or hackthon,
issue, PR are welcome
用 Rust 编写 Ewasm 合约 - Writing Ewasm in Rust
By Antonio Yang
用 Rust 编写 Ewasm 合约 - Writing Ewasm in Rust
The slides provide the general concept to build up an Ewasm contract in Rust. Besides, the pain with ewasm_rust_api are pointed and also provide a framework SewUp try to solve these pain point
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