DETS-backed registry storage. Selected via registry_backend: {:dets, opts} on ProcessHub.t().

Durability

Every successful mutation (insert/3, insert/4, remove/2, clear_all/1) calls :dets.sync/1 before returning, so any operation observed as :ok by the caller is durable on disk.

File location

By default the file is stored at priv/process_hub/<hub_id>/registry.dets resolved against the application's priv directory. Override with the :path option:

registry_backend: {:dets, path: "/var/lib/myapp/hub.dets"}

The parent directory is created if it does not exist.

Recovery on corruption

On open the file is passed repair: true. If :dets.open_file/2 still returns {:error, _}, the corrupt file is rotated to <path>.corrupt-<system_monotonic>, an error is logged, and a fresh empty file is opened at the original path.

TTL

DETS has no native TTL. Entries inserted with :ttl are stored as {key, value, expire_ms} (matching the ETS layout). Reads filter expired entries on the way out. Expired rows are swept by ProcessHub.Worker.Janitor.

Non-replaying open

The DETS file is both the durable medium and the live view for this backend, so recovery_replay: false cannot be implemented by dropping rows — that would destroy the very state a returning node needs. Instead the keys present at open are recorded in a small in-memory shadow set and filtered out of every read; they stay on disk and remain readable through read_durable/1. Writing or removing a key un-shadows it, so a row restored by the orphan reconcile becomes visible again.