Grug

An execution environment for blockchains.

👉 Whitepaper 👈

Overview

Grug consists of the following Rust crates:

crate	description
app	state machine transition logics and Tendermint ABCI implementation
crypto	cryptography functionalities
db/disk	an on-disk, persisted DB backend
db/memory	an in-memory, ephemeral DB backend; used for testing
ffi	helpers for building or interacting with FFI
macros	procedural macros for reducing boilerplates in contract developments
jellyfish-merkle	Jellyfish Merkle Tree (JMT) implementation
storage	abstractions over key-value stores
types	types, traits, and some helper functions
vm/rust	a VM that runs native Rust codes; used for testing
vm/wasm	a VM that runs WebAssembly byte codes

Additionally, there are grug-testing which provides testing utilities, and grug-std, a "meta-crate", which re-exports contents from the above crates, for the convenience of contract developers.

Modularity

At the heart of the project is the grug_app::App type. Fundamentally, a blockchain is a state machine that consists of 1) the state, typically represented by a key-value database, and 2) the state transition rule, which typically involves a virtual machine that runs smart contracts. Therefore, our App takes two generics, representing the DB and the VM, respectively:

struct App<DB, VM> {
    db: DB,
    vm: VM,
}

Here, DB must implement the grug_types::Db trait, while VM must implement the grug_types::Vm trait.

We will ship two Db and two Vm implementations, for different use cases:

use case	implementation
production node	App<DiskDb, WasmVm>
testing	App<MemDb, RustVm>

Dependency graph

The below diagram shows the dependency relations between the crates:

How to use

Prerequisites:

• Rust with wasm32-unknown-unknown target
• Just
• Docker

Install the grug command line software:

just install

Run tests:

just test

Lint the code:

just lint

Compile and optimize smart contracts:

just optimize

Acknowledgement

TODO

License

TBD