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https://github.com/MarinPostma/raft-frp

raft, for regular people
https://github.com/MarinPostma/raft-frp

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raft, for regular people

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# This project is not maintained anymore
# RAFT, for regular people

This is an attempt to create a layer on top of
[tikv/raft-rs](https://github.com/tikv/raft-rs), that is easier to use and
implement. This is not supposed to be the most featureful raft, but instead a
convenient interface to get started quickly, and have a working raft in no
time.

The interface is strongly inspired by the one used by [canonical/raft](https://github.com/canonical/raft).

## Getting started

In order to "raft" storage, we need to implement the `Storage` trait for it.
Bellow is an example with `HashStore`, which is a thread-safe wrapper around an
`HashMap`:

```rust
/// convienient data structure to pass Message in the raft
#[derive(Serialize, Deserialize)]
pub enum Message {
Insert { key: u64, value: String },
}

#[derive(Clone)]
struct HashStore(Arc>>);

impl Store for HashStore {
type Error = RaftError;

fn apply(&mut self, message: &[u8]) -> Result, Self::Error> {
let message: Message = deserialize(message).unwrap();
let message: Vec = match message {
Message::Insert { key, value } => {

let mut db = self.0.write().unwrap();
db.insert(key, value.clone());
serialize(&value).unwrap()
}
};
Ok(message)
}

fn snapshot(&self) -> Vec {
serialize(&self.0.read().unwrap().clone()).unwrap()
}

fn restore(&mut self, snapshot: &[u8]) -> Result<(), Self::Error> {
let new: HashMap = deserialize(snapshot).unwrap();
let mut db = self.0.write().unwrap();
let _ = std::mem::replace(&mut *db, new);
Ok(())
}
}
```

Only 3 methods need to be implemented for the Store:
- `Store::apply`: applies a commited entry to the store.
- `Store::snapshot`: returns snapshot data for the store.
- `Store::apply`: applies the snapshot passed as argument.

### running the raft

```rust
#[tokio::main]
fn main() {
let store = HashStore::new();

let raft = Raft::new(options.raft_addr, store.clone());
let mailbox = Arc::new(raft.mailbox());
let (raft_handle, mailbox) = match options.peer_addr {
Some(addr) => {
info!("running in follower mode");
let handle = tokio::spawn(raft.join(addr));
(handle, mailbox)
}
None => {
info!("running in leader mode");
let handle = tokio::spawn(raft.lead());
(handle, mailbox)
}
};

tokio::join!(raft);
}

```

The `mailbox` gives you a way to interact with the raft, for sending a message, or leaving the cluster for example.