A Ruby implementation of an EventStore based on Active Record.
- Add following line to your application's Gemfile:
gem 'rails_event_store'
- Use provided task to generate a table to store events in you DB.
rails generate rails_event_store:migrate
rake db:migrate
To communicate with ES you have to create instance of RailsEventStore::Client
class.
client = RailsEventStore::Client.new
Firstly you have to define own event model extending RailsEventStore::Event
class.
class OrderCreated < RailsEventStore::Event
end
stream_name = "order_1"
event_data = {
data: { data: "sample" },
event_id: "b2d506fd-409d-4ec7-b02f-c6d2295c7edd"
}
event = OrderCreated.new(event_data)
#publishing event for specific stream
client.publish_event(event, stream_name)
#publishing global event. In this case stream_name is 'all'.
client.publish_event(event)
class OrderCreated < RailsEventStore::Event
end
stream_name = "order_1"
event_data = {
data: { data: "sample" },
event_id: "b2d506fd-409d-4ec7-b02f-c6d2295c7edd"
}
event = OrderCreated.new(event_data)
expected_version = "850c347f-423a-4158-a5ce-b885396c5b73" #last event_id
client.publish_event(event, stream_name, expected_version)
stream_name = "order_1"
start = "850c347f-423a-4158-a5ce-b885396c5b73"
count = 40
client.read_all_events(stream_name, start, count)
This method allows us to load all stream's events ascending.
stream_name = "order_1"
client.read_all_events(stream_name)
This method allows us to load all stored events ascending.
client.read_all_streams
You can permanently delete all events from a specific stream. Use this wisely.
stream_name = "product_1"
client.delete_stream(stream_name)
To listen on specific events synchronously you have to create subscriber reprezentation. The only requirement is that subscriber class has to implement the 'handle_event(event)' method.
class InvoiceReadModel
def handle_event(event)
#we deal here with event's data
end
end
- You can subscribe on specific set of events
invoice = InvoiceReadModel.new
client.subscribe(invoice, ['PriceChanged', 'ProductAdded'])
- You can also listen on all incoming events
invoice = InvoiceReadModel.new
client.subscribe_to_all_events(invoice)
There're already few blogposts about Rails EventStore. Check them out:
- Why use Event Sourcing
- The Event Store for Rails developers
- Fast introduction to Event Sourcing for Ruby programmers
- Why I want to introduce mutation testing to the rails_event_store gem
Rails Event Store is funded and maintained by Arkency. Check out our other open-source projects.
You can also hire us or read our blog.