IEM's ASOS CSV endpoint accepts multiple station= params in a single
request. Prior code enqueued one WeatherFetchWorker job per nearby
station per QSO endpoint — N jobs × 1 station each — which paid the
IemRateLimiter's 1500ms gap and the IEM 429-retry tail N times per
contact.
Changes:
- IemClient.asos_url/3 accepts a list of station codes.
- IemClient.fetch_asos_batch/3 fetches N stations in one call and
returns rows grouped by station_code (with absent codes filled as
empty lists so callers can stub them).
- parse_asos_csv/1 now exposes the station_code column it was
previously discarding.
- WeatherFetchWorker gains an "asos_batch" fetch_type clause that
unpacks rows per (station_id, station_code), upserting or stubbing
each. The single-station "asos" clause stays for already-queued
retryable jobs.
- ContactWeatherEnqueueWorker.build_asos_jobs/3 now emits one batch
job per (lat, lon, 4h window) covering every uncovered nearby
station (sorted for deterministic unique-args).
Expected effect on backfill: ~10-20x fewer IEM requests per contact
enrichment cycle, matching drop in 429 retry traffic.
Graham McIntire
c073c6a95a