67 lines
1.5 KiB
Elixir
67 lines
1.5 KiB
Elixir
defmodule Wiki.MetricStorage do
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use GenServer
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@history_buffer_size 50
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def metrics_history(metric) do
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GenServer.call(__MODULE__, {:data, metric})
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end
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def start_link(args) do
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GenServer.start_link(__MODULE__, args, name: __MODULE__)
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end
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@impl true
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def init(metrics) do
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Process.flag(:trap_exit, true)
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metric_histories_map =
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metrics
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|> Enum.map(fn metric ->
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attach_handler(metric)
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{metric, CircularBuffer.new(@history_buffer_size)}
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end)
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|> Map.new()
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{:ok, metric_histories_map}
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end
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@impl true
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def terminate(_, metrics) do
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for metric <- metrics do
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:telemetry.detach({__MODULE__, metric, self()})
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end
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:ok
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end
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defp attach_handler(%{event_name: name_list} = metric) do
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:telemetry.attach(
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{__MODULE__, metric, self()},
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name_list,
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&__MODULE__.handle_event/4,
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metric
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)
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end
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def handle_event(_event_name, data, metadata, metric) do
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if data = Phoenix.LiveDashboard.extract_datapoint_for_metric(metric, data, metadata) do
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GenServer.cast(__MODULE__, {:telemetry_metric, data, metric})
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end
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end
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@impl true
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def handle_cast({:telemetry_metric, data, metric}, state) do
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{:noreply, update_in(state[metric], &CircularBuffer.insert(&1, data))}
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end
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@impl true
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def handle_call({:data, metric}, _from, state) do
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if history = state[metric] do
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{:reply, CircularBuffer.to_list(history), state}
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else
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{:reply, [], state}
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end
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end
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end
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