Idempotency

Several mutations utilize an idempotency key to allow safely retrying requests without performing operations multiple times. This should be a unique key (typically, a V4 UUID).

For Rafiki’s GraphQL API, whenever a mutation with an idempotencyKey is called, the request payload and the request response are saved under that key. Any subsequent requests made with the same idempotency key will return the original response & status of the request (regardless whether the request was successful or not). Keys are cached for a default of 24 hours, and can be configured via the GRAPHQL_IDEMPOTENCY_KEY_TTL_MS backend service’s environment flag.

Additionally, in the possible chance that a request is made while still concurrently processing the first one under the same idempotencyKey, the API would return an error. This further safeguards from potential errors in the system. The timing to prevent processing concurrent requests can be configured via the GRAPHQL_IDEMPOTENCY_KEY_LOCK_MS flag (which is 2 seconds by default).

For more information on idempotency, see more.