feat: supports ignoring certain exceptions

lib/tower.ex

@@ -330,8 +330,10 @@ defmodule Tower do
   @spec handle_exception(Exception.t(), Exception.stacktrace(), Keyword.t()) :: :ok
   def handle_exception(exception, stacktrace, options \\ [])
       when is_exception(exception) and is_list(stacktrace) do
-    Event.from_exception(exception, stacktrace, options)
-    |> report_event()
+    unless exception.__struct__ in ignored_exceptions() do
+      Event.from_exception(exception, stacktrace, options)
+      |> report_event()
+    end
   end
 
   @doc """
@@ -455,4 +457,8 @@ defmodule Tower do
     Tower.TaskSupervisor
     |> Task.Supervisor.start_child(fun)
   end
+
+  defp ignored_exceptions do
+    Application.fetch_env!(:tower, :ignored_exceptions)
+  end
 end

mix.exs

@@ -32,7 +32,8 @@ defmodule Tower.MixProject do
       extra_applications: [:logger, :inets],
       env: [
         reporters: [Tower.EphemeralReporter],
-        log_level: :critical
+        log_level: :critical,
+        ignored_exceptions: []
       ],
       mod: {Tower.Application, []}
     ]

test/tower_test.exs

@@ -22,7 +22,7 @@
   test "reports arithmetic error" do
     capture_log(fn ->
       in_unlinked_process(fn ->
         1 / 0
       end)
     end)
 
@@ -311,7 +311,7 @@
   test "reports Exception manually" do
     in_unlinked_process(fn ->
       try do
         1 / 0
       catch
         kind, reason ->
           Tower.handle_caught(kind, reason, __STACKTRACE__)
@@ -337,7 +337,7 @@
   test "reports Exception manually (shorthand)" do
     in_unlinked_process(fn ->
       try do
         1 / 0
       rescue
         e ->
           Tower.handle_exception(e, __STACKTRACE__)
@@ -515,7 +515,7 @@
 
     capture_log(fn ->
       in_unlinked_process(fn ->
         1 / 0
       end)
     end)
 
@@ -556,7 +556,7 @@
     capture_log(fn ->
       for _ <- 1..2 do
         in_unlinked_process(fn ->
           1 / 0
         end)
       end
 
@@ -591,6 +591,29 @@
     assert similarity_id != other_similarity_id
   end
 
+  test "doesn't report ignored exceptions" do
+    put_env(:ignored_exceptions, [ArithmeticError])
+
+    capture_log(fn ->
+      in_unlinked_process(fn ->
+        1 / 0
+      end)
+
+      in_unlinked_process(fn ->
+        raise "error"
+      end)
+    end)
+
+    assert_eventually(
+      [
+        %{
+          kind: :error,
+          reason: %RuntimeError{message: "error"}
+        }
+      ] = reported_events()
+    )
+  end
+
   defp in_unlinked_process(fun) when is_function(fun, 0) do
     {:ok, pid} = Task.Supervisor.start_link()