𝗛𝗮𝗻𝗱𝗹𝗶𝗻𝗴 𝗱𝘂𝗽𝗹𝗶𝗰𝗮𝘁𝗲 𝗺𝗲𝘀𝘀𝗮𝗴𝗲𝘀 𝗶𝗻 𝗮𝗻 𝗲𝘃𝗲𝗻𝘁-𝗱𝗿𝗶𝘃𝗲𝗻 𝘀𝘆𝘀𝘁𝗲𝗺
Duplicate messages are a common challenge in event-driven systems. They can arise due to retries after failures, network issues, or even bugs in the message producer. Here's how to handle them: 1. Idempotent Consumers: This is a key approach. An idempotent operation ensures the same outcome even if executed multiple times with the same input. In event processing, this translates to a consumer that performs the same action regardless of receiving the message once or multiple times. There are two main ways to achieve idempotency: Database-based tracking: Store processed message IDs in a separate table. When a message arrives, check if its ID exists in the table. If not, process the message and record the ID. If it does exist, the message is a duplicate and can be safely ignored. https://microservices.io/patterns/communication-style/idempotent-consumer.html Business logic: Design your message handler logic to be inherently idempotent. For example, updating an order state from...