internal/

Package acceptance is packtrail's black-box acceptance suite: every test drives a real engine, real workers and a real embedded nats-server through the public API only, with fault injection (engine kill and restart, NATS restart, duplicate and reordered completions).

Package apierr holds the sentinel errors shared by the public packages, so errors.Is matches them whichever package returned them (a store read by a Client or by a worker job).

Package blob implements the claim-check: a message body larger than the threshold is stored in the blobs object store and the message carries only its name in the Pt-Blob header.

Package cmd defines the commands that drive an execution.

Package conformance is the worker-protocol conformance suite.

Package consume runs a JetStream pull consumer with packtrail's lifecycle: optional pinned priority group (one active consumer per partition with managed failover), bounded concurrency, panic isolation and a graceful drain on shutdown — in-flight handlers keep running under a context detached from the shutdown signal and are only cancelled when the drain budget is exhausted (I-15).

Package dispatch is the projection that turns events into side effects.

Package engine processes commands: for each partition of the command stream it loads the execution state (cache, or snapshot + tail), decides the events with the pure fold, appends them with optimistic concurrency and acks the command.

Package eventlog appends to and reads an execution's event log: the subject <ns>.ev.<partition>.<exec> of the events stream.

Package expr compiles and evaluates the expressions used by flow definitions: choice predicates (`when:`), map sources (`over:`), subflow inputs, search attributes and concurrency keys.

Package fold is the pure heart of packtrail: State is the projection of an execution's events, Apply folds one event into it, and Decide turns a command into the events it produces.

Package infra holds the NATS handles shared by every packtrail component — connection, JetStream context, resource names, partition count — and the provisioning of the streams, buckets and object stores they use.

Package loader rebuilds execution states: snapshot + tail of the log, the flow definition the execution is bound to, and archived executions.

Package metrics counts what the engine does, without any metrics library: the embedding application exports the snapshot however it likes.

Package names centralises every NATS resource name packtrail uses — streams, KV buckets, object stores, subjects and durable consumer names — derived from a single namespace prefix, plus the validation rules for every identifier that ends up as a NATS subject token or KV key segment.

Package natstest starts an embedded, in-process nats-server with JetStream enabled for use in tests.

Package projection maintains the visibility index: a KV projection of every execution's summary plus membership keys by status, flow and declared search attribute, so List/Query never scan the event stream.

Package ready reports whether a process's consumer loops are all pulling, for the run in progress: a readiness probe must not see a run that ended.

Package registry stores flow definitions immutably in KV: key "<name>.<hash>" holds the definition, "<name>.latest" the hash of the most recently registered version.

Package sched holds packtrail's use of JetStream message scheduling: the validator for cron expressions (so a typo fails at registration instead of inside the engine) and the header set for durable one-shot timers and cron schedules.

Package snapshot stores periodic snapshots of execution states in KV: a cache that lets a state be rebuilt from the snapshot plus the tail of the log instead of the whole log.

Package statecache is a bounded in-memory cache of folded execution states.

Package store is the long-term key-value store for application data that outlives executions, shared by clients and worker jobs.

Package wire holds the message formats shared by the engine and the SDKs beyond commands and events: worker jobs, dead letters and cache entries, plus the publish helpers that apply the claim-check and deduplication ids.