SQLite

Embedded durable storage with transactional policy admission and bounded inspection.

SQLite implements Headgate’s complete worker store in both Rust and Go. It evaluates policy, selects work, spends rate capacity, and writes the state, lease, and fence inside one BEGIN IMMEDIATE transaction. The adapter is intended for embedded applications, local development, and small fleets whose write load fits SQLite’s single-writer model.

Rust

let store = std::sync::Arc::new(
    headgate_sqlite::SqliteStore::open("headgate.db").await?
);

Capabilities

SQLite advertises transactions and inspection. This includes transactional enqueue and completion, effects and checkpoints, results, output, progress, schedules, durable events, workers, queue controls, quarantine, and bounded bulk operations.

SQLite deliberately does not advertise notifications. Workers use Headgate’s bounded poll/backoff loop; pretending a polling table were push notification would make the capability contract misleading.

Connection behavior

• File databases use WAL, foreign keys, and a bounded busy timeout.
• :memory: uses one physical connection so the database is not split across a pool.
• Store time—not caller time—drives leases, scheduling, token refill, and duties.
• A bare Go filename is converted to a SQLite file URI before driver options are added.
• The matching embedded schema is installed when the adapter opens. Rust and Go schema bytes are checked for drift by the repository verification gate.

Standalone control API

Set HG_STORE=sqlite and optionally HG_SQLITE=/path/to/headgate.db. Both standalone APIs serve the same control API and embedded console as the other inspection-capable backends.

The shared cross-language corpus runs SQLite through both store implementations and covers fleet-wide rate limiting, fairness under a 5,000-job tenant flood, quarantine, atomic leases, store-clock behavior, and concurrent no-double-claim admission.

SQLite implementation contract