Module carrot_cake::consumers

Facilities to consume messages from a RabbitMq queue. Check out ConsumerGroup as a starting point.

Modules

• hooks
  A collection of ready-made hooks for the most common use cases.

Structs

• ConsumerGroup
  A collection of RabbitMq consumers sharing the same context and connection settings.
• ConsumerGroupBuilder
  A builder to register message handlers once the group-level configuration of a ConsumerGroup has been finalised.
• ConsumerGroupConfigurationBuilder
  A builder for group-level configuration of a ConsumerGroup.
• Delivery
  A received AMQP message.
• HandlerError
  The error type returned by message handlers.
• Incoming
  A dequeued message enriched with some auxiliary data, ready for processing.
• MessageHandler
  A handler processing messages from a RabbitMq queue.
• MessageHandlerBuilder
  A builder to compose a MessageHandler with a fluent API.
• MessageProcessing
  The remainder of the middleware chain (telemetry + processing), including the final message handler.
• Next
  The remainder of the processing middleware chain, including the final message handler.
• ProcessingOutcome
  The outcome of message processing:

Enums

• BrokerAction
  The action we asked the broker to take when finalising the processing of the current message.
• ErrorType
  Types of failure when handling a message. Used by the pub sub framework to handle retries/nacks/dead letter queues/etc.
• ProcessingError
• ShouldRequeue
  Determines if a failed message should be re-queued.

Traits

• ConsumerPreStartHook
  A hook to execute logic before a MessageHandler starts processing messages.
• ConsumerTransientErrorHook
  A hook to determine if failed messages due to a transient error should be requeued.
• Handler
  Implementers of the Handler trait can be used in our RabbitMq MessageHandlers to process messages retrieved from a queue.
• ProcessingMiddleware
  Middlewares to execute logic before and after the message handler function.
• TelemetryMiddleware
  Middlewares to collect and emit telemetry data based on the outcome of message processing.

Functions

• get_message_local_item
  Retrieve an item from message-local storage based on its type.
• set_message_local_item
  Insert an item in message-local storage. If another item with the same type was already stored in message-local storage it gets replaced.