Get Started with ReckonDB

Installation Steps

1. Add the dependencies

ReckonDB is the event store; reckon_evoq is the adapter that wires the evoq CQRS/ES framework onto it. reckon_evoq pulls evoq (and reckon_gater) transitively, so you declare just two:

def deps do
  [
    {:reckon_db, "~> 2.3"},     # BEAM-native event store (Khepri/Ra, Raft)
    {:reckon_evoq, "~> 2.1"}    # evoq → ReckonDB adapter (brings evoq + reckon_gater)
  ]
end

Erlang projects use the same packages in rebar.config.

2. Fetch dependencies

mix deps.get

3. Configure a store and the adapter

Declare a ReckonDB store (it starts at boot) and point evoq at the reckon_evoq adapter for its event store, snapshots, and subscriptions:

# config/config.exs
config :reckon_db,
  stores: [my_store: [mode: :single]]   # data_dir defaults under the app's priv

config :evoq,
  store_id: :my_store,
  event_store_adapter: :reckon_evoq_adapter,
  snapshot_store_adapter: :reckon_evoq_adapter,
  subscription_adapter: :reckon_evoq_adapter

Now model your domain with evoq — commands, events, aggregates and projections — and they persist to ReckonDB through the adapter. See the evoq guides for your first slice.

Benefits

• Raft consensus (Khepri/Ra) — replicated, linearizable event streams with no external coordinator.
• Automatic clustering — nodes self-discover via UDP multicast or Kubernetes DNS and join the Raft group, from a Nerves device to a datacenter.
• Tamper-evident storage — integrity-enabled stores hash-chain events (SHA-256 / Ed25519 crypto NIF); reads against tampered storage fail loudly.
• Optimistic concurrency — versioned appends with expected-version checks for safe concurrent writers.
• Persistent subscriptions — by stream, event type, pattern or payload, with server-side checkpoints.
• Snapshots & projections — aggregate snapshots and projection checkpoints, managed by the adapter.