Event Sourcing and CQRS
Methodologies and patterns for business logic where system state is rebuilt from events.
Product
Odin
Our own technology platform
Shipped
Year2018
The challenge
What the client faced
The task the client came with and why it could not be solved before.
Assembling each project from off-the-shelf libraries means inheriting their limits. We built our own foundation so that we set the architecture instead of accommodating someone else's.
Mechanics
What is inside
The mechanics the product is built from.
Updates without downtime
Functionality is added and changed without pausing the running version or its services.
Multi-datacenter
Deployment across servers for geographic proximity to the client.
A rich API
Connection to any external service — exchanging data through requests or information feeds.
Pipeline
A request through the platform
The path of a request through the platform: from an external system to an answer assembled from the event journal.
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01
A request enters the perimeter
External systems connect over HTTP or WebSocket. The entry point is the router: TLS, request distribution, rate limiting.
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02
A service takes the work
Logic is split into small services. Each owns its part and does not call its neighbours directly.
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03
A change becomes an event
A service does not overwrite state silently — it records an event. The journal restores both the current view of the data and the full history of operations.
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04
The event goes to the broker
The broker delivers it to the other services: queues and topics, guaranteed delivery, reprocessing after a failure.
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05
Read models update separately
Reading and writing are separated: read models are assembled in advance and updated from events, without competing with operations.
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06
The answer goes back
Reads are served from pre-assembled views — fast and without locking writes.
Where it sits
Where it sits
Odin is the bottom layer: both web products and client services stand on it.
Locations
Servers and data centres
The perimeter runs on our own servers and can span several locations, so data sits closer to users.
Odin
Platform components
Message broker, storages, router, orchestration, monitoring. Assembled into a configuration that fits the task.
Products and services
What runs on the platform
Company products and client services: Udeu, Ambitions, back offices, concierge systems.
Outcome
What it gives a product
What those platform properties give a particular product.
A change does not break neighbouring services
Services are tied by contracts and events, not by a shared codebase: changing one does not drag the others along.
Updates without downtime
Two versions of a service run at the same time, so rollout and rollback happen without stopping service.
The history is already there
State is restored from the event journal: investigating what happened needs no separate system.
Reads do not compete with writes
Read models are assembled in advance and updated from events, so reports do not get in the way of operations.
A new service is assembled from ready components
The configuration is chosen for the task — from a single-server installation to a distributed perimeter.
Data closer to the user
Several locations with data replication and traffic switching between them.
Technology
What it is built on
The platform, the stack and the devices the product runs on.
Technologies
- Distributed message broker
- uWebSockets
- RocksDB
- Redis
- Orchestration
- Search engine
Platforms
- Server platform
Links
Where to look
The product website and the materials about it.
Live demo
Demo access is provided on request.
Track record
Projects with this product
Projects where this product is already running.
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