Graham McIntire
2efb35dc48
A scraped product with nil price_per_round_cents made Prices.create_snapshot
return {:error, changeset}, which blew up the {:ok, _} match in the runner,
crashed the whole perform, and after 3 retries discarded the job. Nothing
reseeds the chain once the job is discarded, so prod scrapes silently died
on Mar 17 and stayed dead until the app was restarted.
- Runner handles snapshot insert errors by logging and continuing instead
of raising.
- ScrapeJob wraps each Runner.run in try/rescue so one retailer crashing
doesn't take down the whole cycle.
- ScrapeJob moves schedule_next into an after block so the chain is always
reseeded, even if the scrape loop crashes.
82 lines
2.2 KiB
Elixir
82 lines
2.2 KiB
Elixir
defmodule Ammoprices.Scraping.ScrapeJob do
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@moduledoc false
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use Oban.Worker,
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queue: :scraping,
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max_attempts: 3,
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unique: [period: :infinity, states: [:available, :scheduled, :executing, :retryable]]
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alias Ammoprices.Catalog
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alias Ammoprices.Scraping.Runner
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require Logger
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@scrapers [
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Ammoprices.Scraping.Retailers.LuckyGunner,
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Ammoprices.Scraping.Retailers.SgAmmo,
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Ammoprices.Scraping.Retailers.TargetSportsUsa,
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Ammoprices.Scraping.Retailers.TrueShotAmmo,
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Ammoprices.Scraping.Retailers.PalmettoStateArmory,
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Ammoprices.Scraping.Retailers.BulkAmmo,
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Ammoprices.Scraping.Retailers.Natchez
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]
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# Products not seen for this many days are hard-deleted after each scrape cycle.
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@stale_product_days 30
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@impl Oban.Worker
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def perform(_job) do
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calibers = Catalog.list_calibers()
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for scraper <- @scrapers, caliber <- calibers do
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scrape_delay()
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safe_run(scraper, caliber)
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end
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prune_stale_products()
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Phoenix.PubSub.broadcast(Ammoprices.PubSub, "prices:updated", {:prices_updated, %{}})
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:ok
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after
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# Always reseed the chain, even if something above crashed. Without this,
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# a single unhandled error kills the chain until the app is restarted.
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schedule_next()
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end
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defp safe_run(scraper, caliber) do
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Runner.run(scraper, caliber)
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rescue
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error ->
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Logger.error(
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"Scrape crashed for #{inspect(scraper)} / #{caliber.slug}: " <>
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Exception.format(:error, error, __STACKTRACE__)
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)
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{:error, :crashed}
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end
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defp prune_stale_products do
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cutoff = DateTime.add(DateTime.utc_now(), -@stale_product_days, :day)
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Catalog.delete_stale_products(cutoff)
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end
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@doc false
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def schedule_next do
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{min, max} = Application.get_env(:ammoprices, :scrape_interval_seconds, {25_200, 43_200})
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delay_seconds = Enum.random(min..max)
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%{}
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|> new(scheduled_at: DateTime.add(DateTime.utc_now(), delay_seconds, :second))
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|> Oban.insert()
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end
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# Random delay between requests: 10-20 minutes in prod, 0 in test
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defp scrape_delay do
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{min, max} = Application.get_env(:ammoprices, :scrape_delay_ms, {600_000, 1_200_000})
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delay = Enum.random(min..max)
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if delay > 0 do
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Process.sleep(delay)
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end
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end
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end
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