Messaging
ServiceStack provides a high-level Messaging API exposing a number of essential messaging features in order to publish and receive messages as well as registering and processing handlers for different message types. A class diagram of the core interfaces is below:
There are currently 3 supported MQ Server options:
Like other ServiceStack providers, all MQ Servers are interchangeable, visible in the shared MQ Server tests below:
One of the benefits of using ServiceStack is its integrated support for hosting MQ Servers allowing your Services to be invoked via a MQ Broker. There are a number of reasons why you'd want to use a MQ as an alternative to HTTP including:
- Sender is decoupled from Receiver, eliminating point-to-point coupling and configuration
- Allows no-touch deploy of new clients and servers without updating any configuration
- Removes time-coupling allowing clients and servers to be deployed independently without downtime
- Better reliability, consumers can still send messages when servers are down and vice-versa
- Durable, messages can be persisted and survive application or server reboots
- Allows for CPU Intensive or long operations without disrupting message workflow
- Instant response times by queuing slow operations and executing them in the background
- Allows for natural load-balancing where throughput can be increased by simply adding more processors or servers
- Message-based design allows for easier parallelization and introspection of computations
- Greater throttling and control of message throughput, message execution can be determined by server
- Reduces request contention and can defer execution of high load spikes over time
- Better recovery, messages generating server exceptions can be retried and maintained in a dead-letter-queue
- DLQ messages can be introspected, fixed and later replayed after server updates and rejoin normal message workflow
More details of these and other advantages can be found in the definitive Enterprise Integration Patterns.