README.md

origo-rs

This is a in-memory database that journals commands to disk and replays the commands on startup to recreate the state, the code can be "broken" at any given day, THIS IS A PROOF-OF-CONCEPT PROJECT, just trying things with Rust to learn more about it.

Run server

Run the following in the repository root

## uses .cargo/config.toml
cargo run server

or

RUST_LOG="tide=off, debug" cargo run -r -p server

How it works

Declare your models

// For Origo
use bincode::{Decode, Encode};
use std::collections::HashMap;

#[derive(Encode, Decode, Default)]
pub struct EcomModel {
    pub orders: HashMap<usize, Order>,
}

#[derive(Encode, Decode, Clone)]
pub struct Order {
    pub order_id: usize,
    pub name: String,
    pub transport_id: usize,
}

Declare commands

use crate::models::{EcomModel, Order};
use origo::Command;
// For Origo
use bincode::{Decode, Encode};

#[derive(Encode, Decode)]
pub struct InsertOrder {
    pub order_id: usize,
    pub name: String,
    pub transport_id: usize,
}

impl Command<EcomModel> for InsertOrder {
    fn execute(&self, model: &mut EcomModel) {
        model.orders.insert(
            self.order_id,
            Order {
                order_id: self.order_id,
                name: self.name.clone(),
                transport_id: self.transport_id,
            },
        );
    }
}

Create engine for model, storage and commands

This is done with the origo_engine! macro

origo_engine! {
    MainModelType,
    StorageImplementation,
    CommandTypeToSupport1,
    CommandTypeToSupport2,
    ... more CommandTypesToSupport
};

like this

use origo::origo_engine;
//..
let db = origo_engine! {
    EcomModel,
    DiskStorage::new("./data/test.origors"),
    InsertOrder,
    // Here you keep listing all the commands that the engine should support
};

Usage

Query

let ids = [12, 24, 2285];
let orders: Vec<Order> = db.query(|model| {
    ids.iter()
        .filter_map(|id| model.orders.get(id))
        .cloned()
        .collect()
});

Execute Commands

db.execute(&InsertOrder {
    name: fake_name(),
    order_id: fake_id(),
    transport_id: fake_id(),
});

Snapshots

Configure automatic snapshots by calling snapshot_command_count with the amount of commands allowed before triggering a snapshot.

db.snapshot_command_count(SNAPSHOT_COMMAND_COUNT);

Threading

The engine implements Clone and one instance should be created on startup, then pass clones to threads that needs to execute commands or query data.

The model and storage access internally is wrapped in a RwLock to support multiple reads(queries) or one write(command) at any given time.

let db2 = db.clone();
let handle = thread::spawn(move || {
    db2.execute(&InsertOrder {
        name: fake_name(),
        order_id: fake_id(),
        transport_id: fake_id(),
    });
});