DiscoveryResponse

DiscoveryResponse is a data object used in service discovery protocols to convey the result of a discovery query. It typically reports whether the query succeeded and, when successful, provides the set of services or endpoints that match the request. The response serves as the primary means for clients, load balancers, or orchestration components to learn how to reach available services in a distributed system.

A DiscoveryResponse usually includes several common fields. A status or code indicates success or error conditions. A payload or items list contains the discovered services or endpoints, with each entry typically including a service identifier, host or IP address, port, protocol, and possibly health status. Optional metadata may carry version information, feature flags, weight or shard data for load balancing, and TTL or expiry to guide caching decisions. Some implementations also include error messages or diagnostic details to aid troubleshooting.

Usage scenarios span microservice architectures, edge proxy configurations, and dynamic environments where services scale up or down. The response is generated by a discovery service or API server in response to a query from a client or controller. Clients use the information to route requests, configure clients, or update local caches. Design considerations include correctness, performance, consistency, and the handling of partial or stale data.

See also: service discovery, endpoint discovery, DNS-based discovery, dynamic configuration.