Move OpenTelemetryMonitor to Tracing.Monitor

OpenTelemetryMonitor used to be a fork with a new module named
OpenTelemetryMonitor. This module was proposed as a PR but was not
merged. Dissolving the monitor into Tracing opens the way to be
published.

README.md

@@ -19,7 +19,7 @@ Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_do
 
 ## Setup
 
-Tracing relies on `OpentelemetryMonitor` that should be added to the children list in your `Application.start/2`.
+Tracing relies on `Tracing.Monitor` that should be added to the children list in your `Application.start/2`.
 
 Add `Tracing.setup/1` to `Application.start/2` too with the modules you want to enable telemetry for.
 
@@ -31,7 +31,7 @@ defmodule MyApp.Application do
 
   def start(_type, _args) do
     children = [
-      OpentelemetryMonitor,
+      Tracing.Monitor,
       Tracing.Telemetry,
       # or
       {Tracing.Telemetry, measurements: [], period: 15_000},

lib/tracing.ex

@@ -154,7 +154,7 @@ defmodule Tracing do
       parent_span = OpenTelemetry.Tracer.current_span_ctx()
 
       if unquote(opts)[:monitor] do
-        OpentelemetryMonitor.monitor(parent_span)
+        Tracing.monitor(parent_span)
       end
 
       fn unquote_splicing(fun_args) ->

lib/tracing/monitor.ex

@@ -0,0 +1,56 @@
+defmodule Tracing.Monitor do
+  use GenServer
+
+  def start_link(_arg) do
+    GenServer.start_link(__MODULE__, nil, name: __MODULE__)
+  end
+
+  def init(nil) do
+    _table_id = :ets.new(__MODULE__, [:bag, :public, {:write_concurrency, true}, :named_table])
+    {:ok, nil}
+  end
+
+  def handle_call({:monitor, pid}, _from, state) do
+    Process.monitor(pid)
+    {:reply, :ok, state}
+  end
+
+  def handle_info({:DOWN, _ref, :process, pid, :normal}, state) do
+    :ets.take(__MODULE__, pid)
+    |> Enum.each(fn {_pid, ctx} ->
+      _span_ctx = OpenTelemetry.Tracer.set_current_span(ctx)
+      _ = OpenTelemetry.Tracer.end_span()
+    end)
+
+    {:noreply, state}
+  end
+
+  def handle_info({:DOWN, _ref, :process, pid, {:shutdown, _}}, state) do
+    :ets.take(__MODULE__, pid)
+    |> Enum.each(fn {_pid, ctx} ->
+      _span_ctx = OpenTelemetry.Tracer.set_current_span(ctx)
+      _ = OpenTelemetry.Tracer.end_span()
+    end)
+
+    {:noreply, state}
+  end
+
+  def handle_info({:DOWN, _ref, :process, pid, reason}, state) do
+    :ets.take(__MODULE__, pid)
+    |> Enum.each(fn {_pid, ctx} ->
+      _span_ctx = OpenTelemetry.Tracer.set_current_span(ctx)
+      _ = OpenTelemetry.Tracer.add_event("Process died", [{"reason", inspect(reason)}])
+      _ = OpenTelemetry.Tracer.end_span()
+    end)
+
+    {:noreply, state}
+  end
+
+  def monitor(span_ctx) do
+    if Application.fetch_env!(:opentelemetry, :processors) != [] do
+      # monitor first, because the monitor is necessary to clean the ets table.
+      :ok = GenServer.call(__MODULE__, {:monitor, self()})
+      true = :ets.insert(__MODULE__, {self(), span_ctx})
+    end
+  end
+end

lib/tracing/oban_telemetry.ex

@@ -69,7 +69,7 @@ defmodule Tracing.ObanTelemetry do
     })
     |> Span.set_attributes(attributes)
 
-    OpentelemetryMonitor.monitor(OpenTelemetry.Tracer.current_span_ctx())
+    Tracing.Monitor.monitor(OpenTelemetry.Tracer.current_span_ctx())
   end
 
   def handle_event([:oban, :job, :stop], _, meta, _) do

mix.exs

@@ -40,14 +40,6 @@ defmodule Tracing.MixProject do
       {:opentelemetry_ecto, "~> 1.1"},
       {:opentelemetry_exporter, "~> 1.6"},
       {:opentelemetry_phoenix, "~> 1.2"},
-      {:opentelemetry_phoenix_live_view, "~> 0.1",
-       github: "wuunder/opentelemetry-erlang-contrib",
-       branch: "opentelemetry_phoenix_live_view",
-       sparse: "instrumentation/opentelemetry_phoenix_live_view"},
-      {:opentelemetry_monitor, "~> 0.1",
-       github: "wuunder/opentelemetry-erlang-contrib",
-       branch: "opentelemetry_monitor",
-       sparse: "instrumentation/opentelemetry_monitor"},
       {:opentelemetry_telemetry, "~> 1.0.0"},
       {:telemetry, "~> 1.0"},
       {:telemetry_metrics, "~> 0.4"},
@@ -57,7 +49,7 @@ defmodule Tracing.MixProject do
 
   defp description() do
     """
-      Standardized library for using OpenTelemetry / :telemetry in Elixir applications. 
+      Standardized library for using OpenTelemetry / :telemetry in Elixir applications.
       Provides telemetry modules for Phoenix, LiveView, ChromicPDF and Oban. Also contains a Monitor and Telemetry module."
     """
   end

mix.lock

@@ -18,9 +18,7 @@
   "opentelemetry_api": {:hex, :opentelemetry_api, "1.2.2", "693f47b0d8c76da2095fe858204cfd6350c27fe85d00e4b763deecc9588cf27a", [:mix, :rebar3], [{:opentelemetry_semantic_conventions, "~> 0.2", [hex: :opentelemetry_semantic_conventions, repo: "hexpm", optional: false]}], "hexpm", "dc77b9a00f137a858e60a852f14007bb66eda1ffbeb6c05d5fe6c9e678b05e9d"},
   "opentelemetry_ecto": {:hex, :opentelemetry_ecto, "1.2.0", "2382cb47ddc231f953d3b8263ed029d87fbf217915a1da82f49159d122b64865", [:mix], [{:opentelemetry_api, "~> 1.0", [hex: :opentelemetry_api, repo: "hexpm", optional: false]}, {:opentelemetry_process_propagator, "~> 0.2", [hex: :opentelemetry_process_propagator, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "70dfa2e79932e86f209df00e36c980b17a32f82d175f0068bf7ef9a96cf080cf"},
   "opentelemetry_exporter": {:hex, :opentelemetry_exporter, "1.6.0", "f4fbf69aa9f1541b253813221b82b48a9863bc1570d8ecc517bc510c0d1d3d8c", [:rebar3], [{:grpcbox, ">= 0.0.0", [hex: :grpcbox, repo: "hexpm", optional: false]}, {:opentelemetry, "~> 1.3", [hex: :opentelemetry, repo: "hexpm", optional: false]}, {:opentelemetry_api, "~> 1.2", [hex: :opentelemetry_api, repo: "hexpm", optional: false]}, {:tls_certificate_check, "~> 1.18", [hex: :tls_certificate_check, repo: "hexpm", optional: false]}], "hexpm", "1802d1dca297e46f21e5832ecf843c451121e875f73f04db87355a6cb2ba1710"},
-  "opentelemetry_monitor": {:git, "https://github.com/wuunder/opentelemetry-erlang-contrib.git", "31fb6f51bc0423b40ea777d0029e1d5754b7bf80", [branch: "opentelemetry_monitor", sparse: "instrumentation/opentelemetry_monitor"]},
   "opentelemetry_phoenix": {:hex, :opentelemetry_phoenix, "1.2.0", "b8a53ee595b24970571a7d2fcaef3e4e1a021c68e97cac163ca5d9875fad5e9f", [:mix], [{:nimble_options, "~> 0.5 or ~> 1.0", [hex: :nimble_options, repo: "hexpm", optional: false]}, {:opentelemetry_api, "~> 1.0", [hex: :opentelemetry_api, repo: "hexpm", optional: false]}, {:opentelemetry_process_propagator, "~> 0.2", [hex: :opentelemetry_process_propagator, repo: "hexpm", optional: false]}, {:opentelemetry_semantic_conventions, "~> 0.2", [hex: :opentelemetry_semantic_conventions, repo: "hexpm", optional: false]}, {:opentelemetry_telemetry, "~> 1.0", [hex: :opentelemetry_telemetry, repo: "hexpm", optional: false]}, {:plug, ">= 1.11.0", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "acab991d14ed3efc3f780c5a20cabba27149cf731005b1cc6454c160859debe5"},
-  "opentelemetry_phoenix_live_view": {:git, "https://github.com/wuunder/opentelemetry-erlang-contrib.git", "0bfa1850147d80cdca686bdfc3f1b23cdbf68723", [branch: "opentelemetry_phoenix_live_view", sparse: "instrumentation/opentelemetry_phoenix_live_view"]},
   "opentelemetry_process_propagator": {:hex, :opentelemetry_process_propagator, "0.3.0", "ef5b2059403a1e2b2d2c65914e6962e56371570b8c3ab5323d7a8d3444fb7f84", [:mix, :rebar3], [{:opentelemetry_api, "~> 1.0", [hex: :opentelemetry_api, repo: "hexpm", optional: false]}], "hexpm", "7243cb6de1523c473cba5b1aefa3f85e1ff8cc75d08f367104c1e11919c8c029"},
   "opentelemetry_semantic_conventions": {:hex, :opentelemetry_semantic_conventions, "0.2.0", "b67fe459c2938fcab341cb0951c44860c62347c005ace1b50f8402576f241435", [:mix, :rebar3], [], "hexpm", "d61fa1f5639ee8668d74b527e6806e0503efc55a42db7b5f39939d84c07d6895"},
   "opentelemetry_telemetry": {:hex, :opentelemetry_telemetry, "1.0.0", "d5982a319e725fcd2305b306b65c18a86afdcf7d96821473cf0649ff88877615", [:mix, :rebar3], [{:opentelemetry_api, "~> 1.0", [hex: :opentelemetry_api, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}, {:telemetry_registry, "~> 0.3.0", [hex: :telemetry_registry, repo: "hexpm", optional: false]}], "hexpm", "3401d13a1d4b7aa941a77e6b3ec074f0ae77f83b5b2206766ce630123a9291a9"},

test/tracing/monitor_test.exs

@@ -0,0 +1,4 @@
+defmodule Tracing.MonitorTest do
+  use ExUnit.Case
+  doctest Tracing.Monitor
+end