Resume

The first persistent-resume slice makes the durable event trail sufficient to reconstruct run progress after a restart.

Caution

This is read-only reconstruction, not resumed execution. Reconstruction rebuilds what a run had done from its events; it never starts a resumed run, never re-runs a tool, and never appends an event. Starting a resumed run is a later slice.

Journaling the run

soma_run:init/1 journals the run into run.started as #{steps, run_options}, where run_options is an allowlist of resume-safe metadata: run_id, an optional session_id, and an optional correlation_id. It never journals process-local values (session_pid, the event store, pids, monitor refs, timers, OS pids) or secrets.

Reconstructing progress

soma_run_resume:reconstruct/2 reads soma_event_store:by_run/2 and rebuilds #{run_id, steps, run_options, outputs, next_step, terminal_status}:

• committed step.succeeded outputs keyed by step id;
• the first uncommitted journal step as next_step — a progress marker, not a resume permission;
• the terminal status (completed / failed / timeout / cancelled, else undefined) when a terminal event is present.

%% Pure read: reconstruct progress, never start or mutate a run.
{ok, Progress} = soma_run_resume:reconstruct(Store, RunId).

It rejects a trail with no usable run.started journal ({error, no_run_started_journal}) or one whose committed step id is absent from the journal ({error, {unknown_committed_step, _}}), and is strictly side-effect-free — it never appends events and never starts a run child.