prop/lib/microwaveprop/weather/era5_cds_job.ex
Graham McIntire 1ec10bec1f
Split ERA5 backfill into submit/poll workers with persistent CDS state
The single Era5MonthBatchWorker pinned an Oban slot for the full 30-45
min a CDS month-tile takes to assemble, and lost the work entirely on a
rolling deploy because the in-flight Task died with the pod. This splits
the flow into two tiny workers and persists the CDS job IDs so deploys
survive.

New pipeline:

1. Era5SubmitWorker (:era5_submit queue) — POSTs both CDS requests in
   parallel, writes an `era5_cds_jobs` row with the returned job IDs,
   and enqueues an Era5PollWorker scheduled +5 min. ~1s of real work.
   Short-circuits when the month-tile is already cached or when a row
   already exists (in-flight from a previous attempt).

2. Era5PollWorker (:era5_poll queue) — reads the row, calls
   Era5Client.check_status/1 for both CDS job IDs, and:
     - returns {:snooze, 300} if either job is still running (Oban
       re-schedules without counting an attempt and releases the slot
       immediately — a pod can keep dozens of tile-months in flight
       without pinning workers)
     - streams both GRIB files to disk via Req into: File.stream!,
       decodes via Wgrib2.extract_grid_messages_from_file, bulk-inserts
       via Era5BatchClient.decode_and_insert/6, deletes the row, and
       DELETEs both completed jobs from CDS to free server-side quota
     - if either leg CDS-reports failed, deletes the row + both CDS
       jobs and returns {:error, reason}

Era5Client gains four testable building blocks:
  submit_job/2               (bare POST → {:ok, job_id})
  check_status/1             (GET → :running | {:done, src} | {:failed, reason})
  download_source_to_file/3  (streams {:url, href} or writes {:body, bin})
  delete_job/1               (DELETE /jobs/:id, treats 200/202/204/404 as :ok)

All Req calls now route through `era5_req_options` so tests can stub
CDS responses via Req.Test.stub(Era5Client, fn).

Era5MonthBatchWorker is retained as a thin forwarder to Era5SubmitWorker
so any jobs already in the :era5_batch queue on prod pods drain cleanly
on the next rolling deploy. Safe to delete in a follow-up.

Adds era5_cds_jobs table with a unique index on
(year, month, tile_lat, tile_lon) so duplicate submits collapse.

New queue config in runtime.exs:
  era5_submit: local_limit 4, rate_limit 30/hour (burst protection)
  era5_poll:   local_limit 20 (polls are cheap GETs)
  era5_batch:  kept at 1 for legacy job drain, delete next cycle
2026-04-13 16:26:26 -05:00

44 lines
1.4 KiB
Elixir

defmodule Microwaveprop.Weather.Era5CdsJob do
@moduledoc """
Tracks an in-flight ERA5 CDS request submitted by `Era5SubmitWorker` and
awaiting download+decode by `Era5PollWorker`. Persisting the CDS job IDs
decouples the Oban worker lifecycle from the 30+ minute CDS queue time,
so a pod restart resumes polling instead of re-submitting.
"""
use Ecto.Schema
import Ecto.Changeset
@primary_key {:id, :binary_id, autogenerate: true}
@foreign_key_type :binary_id
schema "era5_cds_jobs" do
field :year, :integer
field :month, :integer
field :tile_lat, :integer
field :tile_lon, :integer
field :single_job_id, :string
field :pressure_job_id, :string
field :submitted_at, :utc_datetime
field :last_polled_at, :utc_datetime
field :poll_count, :integer, default: 0
timestamps(type: :utc_datetime)
end
@type t :: %__MODULE__{}
@required_fields ~w(year month tile_lat tile_lon single_job_id pressure_job_id submitted_at)a
@optional_fields ~w(last_polled_at poll_count)a
@spec changeset(t() | Ecto.Changeset.t(), map()) :: Ecto.Changeset.t()
def changeset(job, attrs) do
job
|> cast(attrs, @required_fields ++ @optional_fields)
|> validate_required(@required_fields)
|> unique_constraint([:year, :month, :tile_lat, :tile_lon],
name: :era5_cds_jobs_year_month_tile_lat_tile_lon_index,
error_key: :tile_month
)
end
end