From 602bcc57a135d3364fcb462f93c886740b035bb9 Mon Sep 17 00:00:00 2001
From: Gonzalo <456459+grzuy@users.noreply.github.com>
Date: Fri, 20 Sep 2024 11:56:29 -0300
Subject: [PATCH] wip poc multiple towers

---
 lib/tower.ex                          | 11 ++++----
 lib/tower/bandit_exception_handler.ex | 10 +++----
 lib/tower/ephemeral_reporter.ex       |  4 +--
 lib/tower/logger_handler.ex           | 10 +++----
 lib/tower/oban_exception_handler.ex   | 10 +++----
 test/tower_multiple_test.exs          | 39 +++++++++++++++++++++++++++
 6 files changed, 62 insertions(+), 22 deletions(-)
 create mode 100644 test/tower_multiple_test.exs

diff --git a/lib/tower.ex b/lib/tower.ex
index cea705c..658cc27 100644
--- a/lib/tower.ex
+++ b/lib/tower.ex
@@ -264,11 +264,12 @@ defmodule Tower do
   Note that `Tower.attach/0` is not a precondition for `Tower` `handle_*` functions to work
   properly and inform reporters. They are independent.
   """
-  @spec attach() :: :ok
-  def attach do
-    :ok = Tower.LoggerHandler.attach()
-    :ok = Tower.BanditExceptionHandler.attach()
-    :ok = Tower.ObanExceptionHandler.attach()
+  @spec attach(atom()) :: :ok
+  def attach(opts \\ []) do
+    {:ok, config} = Tower.Config.from_opts(opts)
+    :ok = Tower.LoggerHandler.attach(Module.concat(name, :LoggerHandler))
+    :ok = Tower.BanditExceptionHandler.attach(Module.concat(name, :BanditExceptionHandler))
+    :ok = Tower.ObanExceptionHandler.attach(Module.concat(name, :ObanExceptionHandler))
   end
 
   @doc """
diff --git a/lib/tower/bandit_exception_handler.ex b/lib/tower/bandit_exception_handler.ex
index 864e805..5f5d86c 100644
--- a/lib/tower/bandit_exception_handler.ex
+++ b/lib/tower/bandit_exception_handler.ex
@@ -3,19 +3,19 @@ defmodule Tower.BanditExceptionHandler do
 
   require Logger
 
-  @handler_id __MODULE__
+  @default_handler_id __MODULE__
 
-  def attach do
+  def attach(handler_id \\ @default_handler_id) do
     :telemetry.attach(
-      @handler_id,
+      handler_id,
       [:bandit, :request, :exception],
       &__MODULE__.handle_event/4,
       _handler_config = []
     )
   end
 
-  def detach do
-    :telemetry.detach(@handler_id)
+  def detach(handler_id \\ @default_handler_id) do
+    :telemetry.detach(handler_id)
   end
 
   def handle_event(
diff --git a/lib/tower/ephemeral_reporter.ex b/lib/tower/ephemeral_reporter.ex
index 1da3094..20689ff 100644
--- a/lib/tower/ephemeral_reporter.ex
+++ b/lib/tower/ephemeral_reporter.ex
@@ -52,7 +52,7 @@ defmodule Tower.EphemeralReporter do
   Returns the list of all stored events.
   """
   @spec events() :: [Tower.Event.t()]
-  def events do
-    Agent.get(__MODULE__, & &1)
+  def events(agent \\ __MODULE__) do
+    Agent.get(agent, & &1)
   end
 end
diff --git a/lib/tower/logger_handler.ex b/lib/tower/logger_handler.ex
index 1edefce..f5e4d79 100644
--- a/lib/tower/logger_handler.ex
+++ b/lib/tower/logger_handler.ex
@@ -1,15 +1,15 @@
 defmodule Tower.LoggerHandler do
   @moduledoc false
 
-  @handler_id Tower
+  @default_handler_id __MODULE__
   @own_logs_domain [:tower, :logger_handler]
 
   require Logger
 
   @spec attach() :: :ok | {:error, term()}
-  def attach do
+  def attach(handler_id \\ @default_handler_id) do
     :logger.add_handler(
-      @handler_id,
+      handler_id,
       __MODULE__,
       %{
         level: :all,
@@ -24,8 +24,8 @@ defmodule Tower.LoggerHandler do
   end
 
   @spec detach() :: :ok | {:error, term()}
-  def detach do
-    :logger.remove_handler(@handler_id)
+  def detach(handler_id \\ @default_handler_id) do
+    :logger.remove_handler(handler_id)
   end
 
   # :logger callbacks
diff --git a/lib/tower/oban_exception_handler.ex b/lib/tower/oban_exception_handler.ex
index b238eef..8282904 100644
--- a/lib/tower/oban_exception_handler.ex
+++ b/lib/tower/oban_exception_handler.ex
@@ -3,19 +3,19 @@ defmodule Tower.ObanExceptionHandler do
 
   require Logger
 
-  @handler_id __MODULE__
+  @default_handler_id __MODULE__
 
-  def attach do
+  def attach(handler_id \\ @default_handler_id) do
     :telemetry.attach(
-      @handler_id,
+      handler_id,
       [:oban, :job, :exception],
       &__MODULE__.handle_event/4,
       _handler_config = []
     )
   end
 
-  def detach do
-    :telemetry.detach(@handler_id)
+  def detach(handler_id \\ @default_handler_id) do
+    :telemetry.detach(handler_id)
   end
 
   def handle_event(
diff --git a/test/tower_multiple_test.exs b/test/tower_multiple_test.exs
new file mode 100644
index 0000000..e5e7fbf
--- /dev/null
+++ b/test/tower_multiple_test.exs
@@ -0,0 +1,39 @@
+defmodule TowerMultipleTest do
+  use ExUnit.Case
+
+  # use AssertEventually, timeout: 100, interval: 10
+
+  # import ExUnit.CaptureLog, only: [capture_log: 1]
+
+  test "multiple towers" do
+    {:ok, ephemeral_reporter_1} = Tower.EphemeralReporter.start_link([])
+    {:ok, ephemeral_reporter_2} = Tower.EphemeralReporter.start_link([])
+
+    assert [] = Tower.EphemeralReporter.events(ephemeral_reporter_1)
+    assert [] = Tower.EphemeralReporter.events(ephemeral_reporter_2)
+
+    spawn(fn -> 1 / 0 end)
+    Process.sleep(200)
+
+    assert [] = Tower.EphemeralReporter.events(ephemeral_reporter_1)
+    assert [] = Tower.EphemeralReporter.events(ephemeral_reporter_2)
+
+    Tower.attach(Tower1, reporters: [{Tower.EphemeralReporter, ephemeral_reporter_1}])
+    Tower.attach(Tower2, reporters: [{Tower.EphemeralReporter, ephemeral_reporter_2}])
+
+    spawn(fn -> 1 / 0 end)
+    Process.sleep(200)
+
+    assert [_event] = Tower.EphemeralReporter.events(ephemeral_reporter_1)
+    assert [_event] = Tower.EphemeralReporter.events(ephemeral_reporter_2)
+
+    :ok = Tower.detach(Tower1)
+
+    spawn(fn -> 1 / 0 end)
+    Process.sleep(200)
+
+    assert [_event] = Tower.EphemeralReporter.events(ephemeral_reporter_1)
+    assert [_event1, _event2] = Tower.EphemeralReporter.events(ephemeral_reporter_2)
+    # :ok = Tower.EphemeralReporter.stop(ephemeral_reporter_1)
+  end
+end