Graham McIntire
250709a1b2
- ScoreCache stores {band, valid_time} as %{{lat, lon} => score} map so
point lookups are O(1); adds fetch_point/4 and valid_times/1
- available_valid_times/1 reads directly from ScoreCache when warm,
falls back to DB on cold start
- point_forecast/3 iterates cached valid_times and uses fetch_point/4
instead of hitting the DB per click
- NexradCache: node-local ETS cache of decoded n0q PNG pixel buffers
keyed by 5-minute rounded timestamp; skips ~1-5s HTTP+decode on
concurrent/repeat clicks within the same window
- MapLive: start_async the rain_scatter fetch so point_detail renders
immediately with a pending marker; push rain_scatter_update when
NEXRAD resolves
- MapLive: preload all 18 remaining forecast hours for the current
viewport after mount/band change/propagation_updated; client caches
them and renders timeline scrubs instantly without a server roundtrip.
Adds set_selected_time event for fast-path state sync.
- Propagation map JS: forecastCache map + drawScatterMarkers helper,
timeline click uses preloaded cache when available
55 lines
1.6 KiB
Elixir
55 lines
1.6 KiB
Elixir
defmodule Microwaveprop.Weather.NexradCache do
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@moduledoc """
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Node-local ETS cache of decoded NEXRAD n0q composite reflectivity frames.
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Keyed by a 5-minute rounded timestamp. Stores the raw pixel buffer + image
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width so per-point rain-cell extraction can skip the HTTP fetch + PNG decode
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(which take 1-5 seconds for a ~5 MB CONUS-wide image).
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The cache is populated by `Microwaveprop.Weather.NexradClient.fetch_rain_cells/4`
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on its first call per 5-min window, then reused by every concurrent click
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until the window rolls over.
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"""
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use GenServer
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@table :nexrad_frame_cache
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@type pixels :: binary()
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@type width :: pos_integer()
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@spec start_link(keyword()) :: GenServer.on_start()
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def start_link(opts) do
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GenServer.start_link(__MODULE__, opts, name: __MODULE__)
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end
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@spec fetch(DateTime.t()) :: {:ok, pixels(), width()} | :miss
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def fetch(rounded_ts) do
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case :ets.lookup(@table, rounded_ts) do
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[{_, pixels, width}] -> {:ok, pixels, width}
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[] -> :miss
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end
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end
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@spec put(DateTime.t(), pixels(), width()) :: :ok
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def put(rounded_ts, pixels, width) do
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:ets.insert(@table, {rounded_ts, pixels, width})
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:ok
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end
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@spec prune_older_than(DateTime.t()) :: non_neg_integer()
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def prune_older_than(cutoff_ts) do
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match_spec = [{{:"$1", :_, :_}, [{:<, :"$1", {:const, cutoff_ts}}], [true]}]
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:ets.select_delete(@table, match_spec)
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end
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@spec clear() :: :ok
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def clear do
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:ets.delete_all_objects(@table)
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:ok
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end
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@impl true
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def init(_opts) do
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:ets.new(@table, [:set, :named_table, :public, read_concurrency: true])
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{:ok, %{}}
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end
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end
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