Could someone explain the canonical approach to deduplicating Genesys Cloud events arriving via EventBridge? We are seeing near-identical events for userStatus changes, likely due to GC internal retries or race conditions between the webhook firehose and EventBridge rule evaluation.
Current Lambda handler:
exports.handler = async (event) => {
const records = event.Records;
for (const record of records) {
const body = JSON.parse(record.body);
// body.eventId is unique per GC webhook, but EventBridge may re-deliver?
console.log(body.eventId);
await processUserStatus(body);
}
};
The body.eventId from the original Genesys Cloud webhook payload is preserved in the EventBridge detail. However, EventBridge rules can trigger multiple times if the target (SQS) acknowledges late or if there are overlapping rule evaluations. We cannot rely solely on body.eventId if EventBridge generates a new event-id for its own delivery envelope.
Are we supposed to implement an idempotency key check against a DynamoDB table using the Genesys Cloud event-id? Or is there a specific header or field in the EventBridge payload that guarantees uniqueness across retries? We want to avoid processing the same status change twice in our downstream Terraform-managed state sync.
This is caused by EventBridge’s default EventFilter not handling GC’s idempotency keys correctly. Configure the rule to filter on detail-type and source, then use ContentBasedDeduplication in SQS to drop duplicates based on the webhook id field.
The main issue here is that relying solely on SQS ContentBasedDeduplication for Genesys Cloud webhook events is insufficient because the GC webhook payload structure often contains timestamp-based fields or transient session IDs that change with every retry, causing the message body hash to differ even for logically identical events. The suggestion above regarding EventBridge filtering is useful for routing, but it does not solve the duplication at the ingestion layer.
In my experience building custom triggers for Zapier, the most robust method is to implement a custom deduplication key based on the immutable event.id or resource_id combined with a short time window in your Lambda handler. You must parse the incoming EventBridge detail object and extract the unique event identifier before processing.
Here is how you should structure the deduplication logic in your Lambda handler using a simple in-memory or DynamoDB TTL-based cache. The key is to normalize the payload by stripping volatile fields before generating the hash.
In your Node.js Lambda, extract detail.event.id. If this ID exists in your recent cache (e.g., last 5 minutes), return early with a success status to prevent downstream processing. If it is new, store the ID with a TTL and process the event. This approach ensures idempotency regardless of the slight variations in the full JSON body caused by GC’s retry mechanism. Do not rely on the full message body hash as suggested previously, as it is brittle against timestamp jitter.