gocron v2's WithLocation is a SchedulerOption (process-wide), not a
JobOption — there's no per-job location knob. To get per-user
timezones we use a cron expression with the CRON_TZ= prefix, which
the underlying robfig/cron parser honors:
CRON_TZ=America/New_York 0 3 * * *
Fires at 03:00 in the named zone every day. Same DST-correctness as
the original WithLocation approach.
Fall-back to UTC moves inline (was validateTimezoneOrUTC); kept the
helper because the test file still exercises it.
Caught by go vet on CI after slice 2 pushed:
"cannot use gocron.WithLocation(loc) (value of type
gocron.SchedulerOption) as gocron.JobOption value"
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Builds the per-user daily-at-03:00-local scheduler for #392 Half B.
Uses github.com/go-co-op/gocron/v2 with WithLocation(userTZ) for
each user's job. Hourly reconciliation pass keeps the in-memory
job set in sync with the active-users query.
Start sequence: clear stale in_flight rows; register a daily job
for every active user at their stored timezone; fire a one-shot
runOnce to catch up missed schedules during downtime; start gocron.
Stop drains and shuts down the gocron loop.
Refresh(ctx, userID) removes the user's existing job (if any) and
registers a fresh one at their current timezone — wired into the
PUT /api/me/timezone handler and new-user registration in the next
commit.
Server struct gains PlaylistScheduler; main.go constructs it after
the eventbus and threads it through to api.Mount. The existing
StartSystemPlaylistCron call stays for one more commit so we don't
have a window where no scheduler is running; Task 3 deletes it.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
bvandeusen