redis_streams_event_sourcing

📈 Implement Event Sourcing with Redis Streams

Redis Streams provide an append‑only log ideal for event sourcing, offering instant fan‑out and consumer groups for guaranteed, scalable processing. By modeling state changes as discrete events, you can rebuild application state at any point and handle back‑pressure gracefully. Use XADD to log events, XREADGROUP for consumers, and XACK to mark successes.

# publisher.rb
event = {id: SecureRandom.uuid, type: 'OrderCreated', payload: {order_id: 42, total: 99.99}}
$redis.xadd('orders:stream', '*', event)

# consumer.rb
group = 'order_processors'
stream = 'orders:stream'
begin
  $redis.xgroup('CREATE', stream, group, '$', mkstream: true)
rescue Redis::CommandError; end

loop do
  entries = $redis.xreadgroup(group, 'consumer-1', {stream => '>'}, count: 10, block: 5_000)
  next unless entries

  entries.each do |_, msgs|
    msgs.each do |id, data|
      process_order(data)
      $redis.xack(stream, group, id)
    end
  end
end