Attach pool_size metrics in poolex_example app (#82)

Author: general-CbIC

examples/poolex_example/lib/poolex_example/application.ex

@@ -9,9 +9,17 @@ defmodule PoolexExample.Application do
        pool_id: :worker_pool,
        worker_module: PoolexExample.Worker,
        workers_count: 5,
-       max_overflow: 2}
+       max_overflow: 2,
+       pool_size_metrics: true}
     ]
 
+    :telemetry.attach(
+      "poolex_metrics",
+      [:poolex, :metrics, :pool_size],
+      &PoolexExample.MetricsHandler.handle_event/4,
+      nil
+    )
+
     Supervisor.start_link(children, strategy: :one_for_one)
   end
 end

examples/poolex_example/lib/poolex_example/metrics_handler.ex

@@ -0,0 +1,10 @@
+defmodule PoolexExample.MetricsHandler do
+  def handle_event([:poolex, :metrics, :pool_size], measurements, metadata, _config) do
+    IO.puts("""
+    [Pool: #{metadata.pool_id}]:
+    - Idle workers: #{measurements.idle_workers_count}
+    - Busy workers: #{measurements.busy_workers_count}
+    - Overflowed: #{measurements.overflowed}
+    """)
+  end
+end

examples/poolex_example/mix.exs

@@ -21,8 +21,9 @@ defmodule PoolexExample.MixProject do
   # Run "mix help deps" to learn about dependencies.
   defp deps do
     [
+      {:dialyxir, "~> 1.0", only: [:dev, :test], runtime: false},
       {:poolex, path: "../.."},
-      {:dialyxir, "~> 1.0", only: [:dev, :test], runtime: false}
+      {:telemetry, "~> 1.0"}
     ]
   end
 end

examples/poolex_example/mix.lock

@@ -1,5 +1,7 @@
 %{
-  "dialyxir": {:hex, :dialyxir, "1.2.0", "58344b3e87c2e7095304c81a9ae65cb68b613e28340690dfe1a5597fd08dec37", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "61072136427a851674cab81762be4dbeae7679f85b1272b6d25c3a839aff8463"},
+  "dialyxir": {:hex, :dialyxir, "1.4.3", "edd0124f358f0b9e95bfe53a9fcf806d615d8f838e2202a9f430d59566b6b53b", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "bf2cfb75cd5c5006bec30141b131663299c661a864ec7fbbc72dfa557487a986"},
   "erlex": {:hex, :erlex, "0.2.6", "c7987d15e899c7a2f34f5420d2a2ea0d659682c06ac607572df55a43753aa12e", [:mix], [], "hexpm", "2ed2e25711feb44d52b17d2780eabf998452f6efda104877a3881c2f8c0c0c75"},
   "poolex": {:hex, :poolex, "0.4.0", "cc3c5eb921a2ea5886953a2ea3beb0e36148d7d91dd9b628df74c3abb5ea7981", [:mix], [], "hexpm", "0441bf433f8fca4127b68c5985354cb772bba049057bca842f6e73df4f631c17"},
+  "telemetry": {:hex, :telemetry, "1.2.1", "68fdfe8d8f05a8428483a97d7aab2f268aaff24b49e0f599faa091f1d4e7f61c", [:rebar3], [], "hexpm", "dad9ce9d8effc621708f99eac538ef1cbe05d6a874dd741de2e689c47feafed5"},
+  "telemetry_poller": {:hex, :telemetry_poller, "1.0.0", "db91bb424e07f2bb6e73926fcafbfcbcb295f0193e0a00e825e589a0a47e8453", [:rebar3], [{:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "b3a24eafd66c3f42da30fc3ca7dda1e9d546c12250a2d60d7b81d264fbec4f6e"},
 }