TTFQuit

TTFQuit is a term used in computing to describe a standardized signal and accompanying tooling for gracefully terminating tasks in multi-tenant and distributed systems. It provides a minimal protocol and library interfaces to coordinate shutdown across workers, services, and orchestrators, enabling in-flight work to complete safely and state to be flushed before termination.

Origin and scope: The term is not a formal standard. It appears in a variety of open-source projects and design proposals as a lightweight mechanism to request shutdown. The acronym is used with different expansions, such as Task Termination Framework Quit, but the common idea is a portable quit signal rather than a specific implementation.

Protocol and message model: The core concept is a TTFQuit signal that can be delivered over standard transports (HTTP, gRPC, message queues). A typical message includes fields like timestamp, reason, requester identity, and a nonce to prevent replay. Two modes are commonly supported: soft quit, which allows in-flight tasks to finish within a timeout, and hard quit, which terminates tasks immediately.

Lifecycle and handling: On receipt, a service transitions to shutdown mode, stops accepting new work, and attempts to complete or cancel in-flight tasks according to mode. It flushes state, drains logs, closes connections, and acknowledges completion back to the initiator or orchestrator.

Implementation and security: Several language bindings exist in experimental form, with adapters for common frameworks and schedulers. Security considerations include authenticating quit requests, using TLS, and ensuring idempotent handling to survive retries.

Reception and evaluation: Because it lacks formal standardization, adoption is uneven across projects. Proponents cite predictable and safe shutdowns, while critics point to added complexity and fragmentation. As a concept, TTFQuit illustrates a general need for coordinated termination in distributed systems.