forked from
l4.pm/atvouch
dev vouch dev on at. thats about it
add counter task
+81
-1
+2
-1
appview/lib/atvouch/application.ex
+2
-1
appview/lib/atvouch/application.ex
···
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children =
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repos() ++
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[
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-
{Bandit, plug: Atvouch.Router, port: port, ip: {127, 0, 0, 1}}
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+
{Bandit, plug: Atvouch.Router, port: port, ip: {127, 0, 0, 1}},
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Atvouch.Tinycron.new(Atvouch.CounterTask, every: 60, jitter: -5..5)
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] ++ tap_children()
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opts = [strategy: :one_for_one, name: Atvouch.Supervisor]
+14
appview/lib/atvouch/counter_task.ex
+14
appview/lib/atvouch/counter_task.ex
···
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defmodule Atvouch.CounterTask do
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require Logger
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use Prometheus.Metric
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def tick do
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identities_count = Atvouch.Repo.aggregate(Atvouch.Identity, :count)
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vouches_count = Atvouch.Repo.aggregate(Atvouch.Vouch, :count)
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+
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Gauge.set([name: :identities_total], identities_count)
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Gauge.set([name: :vouches_total], vouches_count)
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Logger.debug("counters: identities=#{identities_count} vouches=#{vouches_count}")
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end
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end
+10
appview/lib/atvouch/telemetry.ex
+10
appview/lib/atvouch/telemetry.ex
···
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labels: [:method, :route, :status]
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)
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+
Gauge.declare(
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name: :identities_total,
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help: "Total number of identities"
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)
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+
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Gauge.declare(
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name: :vouches_total,
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help: "Total number of vouches"
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)
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+
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:telemetry.attach(
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@handler_id,
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[:bandit, :request, :stop],
+55
appview/lib/atvouch/tinycron.ex
+55
appview/lib/atvouch/tinycron.ex
···
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defmodule Atvouch.Tinycron do
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use GenServer
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require Logger
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+
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def new(module, opts \\ []) do
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%{
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id: module,
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start: {__MODULE__, :start_link, [module, opts |> Keyword.put(:name, module)]}
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}
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end
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+
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def start_link(module, opts \\ []) do
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GenServer.start_link(__MODULE__, [module, opts], opts)
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end
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+
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def noop(mod, value) do
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GenServer.cast(mod, {:noop, value})
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end
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@impl true
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def init([module, opts]) do
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state = %{module: module, opts: opts}
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schedule_work(state)
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{:ok, state}
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end
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+
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@impl true
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def handle_info(:work, %{module: module} = state) do
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unless state |> Map.get(:noop, false) do
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Logger.debug("running #{inspect(state.module)}")
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module.tick()
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end
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schedule_work(state)
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{:noreply, state}
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end
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+
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@impl true
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def handle_cast({:noop, value}, state) do
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{:noreply, state |> Map.put(:noop, value)}
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end
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+
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defp schedule_work(state) do
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every_seconds = state.opts |> Keyword.get(:every) || 10
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jitter_seconds_range = state.opts |> Keyword.get(:jitter) || -2..2
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first..last//step = jitter_seconds_range
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# turn it into milliseconds for greater jitter possibilities
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jitter_milliseconds_range = (first * 1000)..(last * 1000)//step
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+
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# prevent jitter from creating negative next_tick_time by doing max(0, next_tick_time)
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next_tick_time = max(0, every_seconds * 1000 + Enum.random(jitter_milliseconds_range))
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Logger.debug("scheduling #{inspect(state.module)} in #{next_tick_time}ms")
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Process.send_after(self(), :work, next_tick_time)
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end
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end