Reduce ETSCronFlusher memory consumption

lib/prom_ex.ex

@@ -128,6 +128,19 @@ defmodule PromEx do
       else: :prom_ex_down
   end
 
+  @doc """
+  Forces aggregation for all currently configured distributions (histogram). This is
+  primarily used by flusher process to prevent high memory consumptions.
+  """
+  @spec aggregate_metrics(prom_ex_module :: module()) :: :ok | :prom_ex_down
+  def aggregate_metrics(prom_ex_module) do
+    prom_ex_process_name = prom_ex_module.__metrics_collector_name__()
+
+    if Process.whereis(prom_ex_process_name),
+      do: Core.aggregate(prom_ex_process_name),
+      else: :prom_ex_down
+  end
+
   @callback init_opts :: PromEx.Config.t()
   @callback plugins :: [plugin_definition()]
   @callback dashboard_assigns :: keyword()

lib/prom_ex/ets_cron_flusher.ex

@@ -48,10 +48,10 @@ defmodule PromEx.ETSCronFlusher do
 
   @impl true
   def handle_info(:flush_ets, state) do
-    PromEx.get_metrics(state.prom_ex_module)
+    PromEx.aggregate_metrics(state.prom_ex_module)
 
     timer_ref = schedule_flush(state)
-    {:noreply, %{state | timer_ref: timer_ref}}
+    {:noreply, %{state | timer_ref: timer_ref}, :hibernate}
   end
 
   @impl true

mix.exs

@@ -59,7 +59,7 @@ defmodule PromEx.MixProject do
       {:telemetry, ">= 1.0.0"},
       {:telemetry_poller, "~> 1.0"},
       {:telemetry_metrics, "~> 0.6"},
-      {:telemetry_metrics_prometheus_core, "~> 1.0"},
+      {:telemetry_metrics_prometheus_core, github: "IIILSW/telemetry_metrics_prometheus_core"},
       {:plug_cowboy, "~> 2.5 or ~> 2.6"},
       {:octo_fetch, "~> 0.3"},
 

mix.lock

@@ -56,7 +56,7 @@
   "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.6", "cf344f5692c82d2cd7554f5ec8fd961548d4fd09e7d22f5b62482e5aeaebd4b0", [:make, :mix, :rebar3], [], "hexpm", "bdb0d2471f453c88ff3908e7686f86f9be327d065cc1ec16fa4540197ea04680"},
   "telemetry": {:hex, :telemetry, "1.0.0", "0f453a102cdf13d506b7c0ab158324c337c41f1cc7548f0bc0e130bbf0ae9452", [:rebar3], [], "hexpm", "73bc09fa59b4a0284efb4624335583c528e07ec9ae76aca96ea0673850aec57a"},
   "telemetry_metrics": {:hex, :telemetry_metrics, "0.6.1", "315d9163a1d4660aedc3fee73f33f1d355dcc76c5c3ab3d59e76e3edf80eef1f", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "7be9e0871c41732c233be71e4be11b96e56177bf15dde64a8ac9ce72ac9834c6"},
-  "telemetry_metrics_prometheus_core": {:hex, :telemetry_metrics_prometheus_core, "1.0.2", "c98b1c580de637bfeac00db41b9fb91fb4c3548ee3d512a8ed7299172312eaf3", [:mix], [{:telemetry, "~> 0.4 or ~> 1.0.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:telemetry_metrics, "~> 0.6", [hex: :telemetry_metrics, repo: "hexpm", optional: false]}], "hexpm", "48351a0d56f80e38c997b44232b1043e0a081670d16766eee920e6254175b730"},
+  "telemetry_metrics_prometheus_core": {:git, "https://github.com/IIILSW/telemetry_metrics_prometheus_core.git", "a90f72a65fec1e21840fda4c0fc41d589525e114", []},
   "telemetry_poller": {:hex, :telemetry_poller, "1.0.0", "db91bb424e07f2bb6e73926fcafbfcbcb295f0193e0a00e825e589a0a47e8453", [:rebar3], [{:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b3a24eafd66c3f42da30fc3ca7dda1e9d546c12250a2d60d7b81d264fbec4f6e"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"},
 }