[Feature] Notification delivery throttling timeout

.gitignore

@@ -23,4 +23,4 @@ erl_crash.dump
 boom-*.tar
 
 .DS_Store
-priv/
+/priv/

README.md

@@ -149,6 +149,26 @@ defmodule YourApp.Router do
     ]
 ```
 
+### Notification trigger timeout
+
+If you've defined a triggering strategy which holds off notification delivering you can define a timeout value
+which will be used to deliver the notification after timeout milliseconds have passed from the last error. The
+timeout counter is reset on new errors and only applies for cases where notifications are not sent.
+
+```elixir
+defmodule YourApp.Router do
+  use Phoenix.Router
+
+  use BoomNotifier,
+    notification_trigger: [:exponential],
+    throttle_timeout: :timer.minutes(30),
+    notifier: CustomNotifier
+
+  # ...
+end
+```
+
+
 ## Custom data or Metadata
 
 By default, `BoomNotifier` will **not** include any custom data from your

lib/boom_notifier.ex

@@ -3,55 +3,10 @@ defmodule BoomNotifier do
 
   # Responsible for sending a notification to each notifier every time an
   # exception is raised.
-
-  alias BoomNotifier.ErrorInfo
-  alias BoomNotifier.ErrorStorage
-  alias BoomNotifier.NotifierSenderServer
   require Logger
 
-  def run_callback(settings, callback) do
-    missing_keys = Enum.reject([:notifier, :options], &Keyword.has_key?(settings, &1))
-
-    case missing_keys do
-      [] ->
-        callback.(settings[:notifier], settings[:options])
-
-      [missing_key] ->
-        Logger.error("(BoomNotifier) #{inspect(missing_key)} parameter is missing")
-
-      _ ->
-        Logger.error(
-          "(BoomNotifier) The following parameters are missing: #{inspect(missing_keys)}"
-        )
-    end
-  end
-
-  def walkthrough_notifiers(settings, callback) do
-    case Keyword.get(settings, :notifiers) do
-      nil ->
-        run_callback(settings, callback)
-
-      notifiers_settings when is_list(notifiers_settings) ->
-        Enum.each(notifiers_settings, &run_callback(&1, callback))
-    end
-  end
-
-  def validate_notifiers(notifier, options) do
-    if Code.ensure_loaded?(notifier) && function_exported?(notifier, :validate_config, 1) do
-      case notifier.validate_config(options) do
-        {:error, message} ->
-          Logger.error(
-            "Notifier validation: #{message} in #{notifier |> to_string() |> String.split(".") |> List.last()}"
-          )
-
-        _ ->
-          nil
-      end
-    end
-  end
-
   defmacro __using__(config) do
-    quote do
+    quote location: :keep, bind_quoted: [config: config] do
       import BoomNotifier
 
       error_handler_in_use = Plug.ErrorHandler in @behaviour
@@ -68,44 +23,13 @@ defmodule BoomNotifier do
       end
 
       # Notifiers validation
-      walkthrough_notifiers(
-        unquote(config),
-        fn notifier, options -> validate_notifiers(notifier, options) end
+      BoomNotifier.Api.walkthrough_notifiers(
+        config,
+        fn notifier, options -> BoomNotifier.Api.validate_notifiers(notifier, options) end
       )
 
-      def notify_error(conn, %{kind: :error, reason: %mod{}} = error) do
-        settings = unquote(config)
-        {ignored_exceptions, _settings} = Keyword.pop(settings, :ignore_exceptions, [])
-
-        unless Enum.member?(ignored_exceptions, mod) do
-          do_notify_error(conn, settings, error)
-        end
-      end
-
       def notify_error(conn, error) do
-        do_notify_error(conn, unquote(config), error)
-      end
-
-      defp do_notify_error(conn, settings, error) do
-        {custom_data, _settings} = Keyword.pop(settings, :custom_data, :nothing)
-        error_info = ErrorInfo.build(error, conn, custom_data)
-
-        ErrorStorage.store_error(error_info)
-
-        if ErrorStorage.send_notification?(error_info) do
-          notification_data =
-            Map.put(error_info, :occurrences, ErrorStorage.get_error_stats(error_info))
-
-          # Triggers the notification in each notifier
-          walkthrough_notifiers(settings, fn notifier, options ->
-            NotifierSenderServer.send(notifier, notification_data, options)
-          end)
-
-          {notification_trigger, _settings} =
-            Keyword.pop(settings, :notification_trigger, :always)
-
-          ErrorStorage.reset_accumulated_errors(notification_trigger, error_info)
-        end
+        BoomNotifier.Api.notify_error(unquote(config), conn, error)
       end
     end
   end

lib/boom_notifier/api.ex

@@ -0,0 +1,70 @@
+defmodule BoomNotifier.Api do
+  @moduledoc """
+  BoomNotifier Entrypoint API
+
+  Define functions required by BoomNotifier module when used on a plug app.
+  """
+  require Logger
+
+  alias BoomNotifier.ErrorInfo
+  alias BoomNotifier.NotificationSender
+
+  def notify_error(settings, conn, %{kind: :error, reason: %mod{}} = error) do
+    ignored_exceptions = Keyword.get(settings, :ignore_exceptions, [])
+
+    unless Enum.member?(ignored_exceptions, mod) do
+      trigger_notify_error(settings, conn, error)
+    end
+  end
+
+  def notify_error(settings, conn, error),
+    do: trigger_notify_error(settings, conn, error)
+
+  def walkthrough_notifiers(settings, callback) do
+    case Keyword.get(settings, :notifiers) do
+      nil ->
+        run_callback(settings, callback)
+
+      notifiers_settings when is_list(notifiers_settings) ->
+        Enum.each(notifiers_settings, &run_callback(&1, callback))
+    end
+  end
+
+  def validate_notifiers(notifier, options) do
+    if Code.ensure_loaded?(notifier) && function_exported?(notifier, :validate_config, 1) do
+      case notifier.validate_config(options) do
+        {:error, message} ->
+          Logger.error(
+            "Notifier validation: #{message} in #{notifier |> to_string() |> String.split(".") |> List.last()}"
+          )
+
+        _ ->
+          nil
+      end
+    end
+  end
+
+  defp run_callback(settings, callback) do
+    missing_keys = Enum.reject([:notifier, :options], &Keyword.has_key?(settings, &1))
+
+    case missing_keys do
+      [] ->
+        callback.(settings[:notifier], settings[:options])
+
+      [missing_key] ->
+        Logger.error("(BoomNotifier) #{inspect(missing_key)} parameter is missing")
+
+      _ ->
+        Logger.error(
+          "(BoomNotifier) The following parameters are missing: #{inspect(missing_keys)}"
+        )
+    end
+  end
+
+  defp trigger_notify_error(settings, conn, error) do
+    custom_data = Keyword.get(settings, :custom_data, :nothing)
+    error_info = ErrorInfo.build(error, conn, custom_data)
+
+    NotificationSender.async_trigger_notify(settings, error_info)
+  end
+end

lib/boom_notifier/application.ex

@@ -6,7 +6,7 @@ defmodule BoomNotifier.Application do
   def start(_type, _args) do
     children = [
       BoomNotifier.ErrorStorage,
-      BoomNotifier.NotifierSenderServer
+      BoomNotifier.NotificationSender
     ]
 
     Supervisor.start_link(children, strategy: :one_for_one)

lib/boom_notifier/error_info.ex

@@ -8,6 +8,7 @@ defmodule BoomNotifier.ErrorInfo do
 
   @enforce_keys [:reason, :stack, :timestamp]
   defstruct [
+    :key,
     :name,
     :reason,
     :stack,
@@ -50,6 +51,7 @@ defmodule BoomNotifier.ErrorInfo do
       name: error_name,
       metadata: build_custom_data(conn, custom_data_strategy)
     }
+    |> ensure_key()
   end
 
   defp error_reason(%name{message: reason}), do: {reason, name}
@@ -116,4 +118,29 @@ defmodule BoomNotifier.ErrorInfo do
       Enum.reduce(options, %{}, fn opt, acc ->
         Map.merge(acc, build_custom_data(conn, opt))
       end)
+
+  # Generates a unique hash key based on the error info. The timestamp and the
+  # request info is removed so we don't get different keys for the same error.
+  #
+  # The map is converted to a string using `inspect()` so we can hash it using
+  # the crc32 algorithm that was taken from the Exception Notification library
+  # for Rails
+  @spec generate_error_key(__MODULE__.t()) :: non_neg_integer()
+  def generate_error_key(error_info) do
+    error_info
+    |> Map.delete(:request)
+    |> Map.delete(:metadata)
+    |> Map.delete(:timestamp)
+    |> Map.update(:stack, nil, fn stacktrace -> List.first(stacktrace) end)
+    |> inspect()
+    |> :erlang.crc32()
+  end
+
+  def ensure_key(%{key: nil} = error_info) do
+    error_info |> Map.put(:key, generate_error_key(error_info))
+  end
+
+  def ensure_key(%{} = error_info) do
+    error_info |> Map.put_new_lazy(:key, fn -> generate_error_key(error_info) end)
+  end
 end

lib/boom_notifier/error_storage.ex

@@ -34,7 +34,7 @@ defmodule BoomNotifier.ErrorStorage do
   """
   @spec store_error(ErrorInfo.t()) :: :ok
   def store_error(error_info) do
-    error_hash_key = generate_error_key(error_info)
+    %{key: error_hash_key} = ErrorInfo.ensure_key(error_info)
     timestamp = error_info.timestamp || DateTime.utc_now()
 
     default_error_storage_info = %__MODULE__{
@@ -67,7 +67,7 @@ defmodule BoomNotifier.ErrorStorage do
   """
   @spec get_error_stats(ErrorInfo.t()) :: %__MODULE__{}
   def get_error_stats(error_info) do
-    error_hash_key = generate_error_key(error_info)
+    %{key: error_hash_key} = ErrorInfo.ensure_key(error_info)
 
     Agent.get(:boom_notifier, fn state -> state end)
     |> Map.get(error_hash_key)
@@ -81,7 +81,7 @@ defmodule BoomNotifier.ErrorStorage do
   """
   @spec send_notification?(ErrorInfo.t()) :: boolean()
   def send_notification?(error_info) do
-    error_hash_key = generate_error_key(error_info)
+    %{key: error_hash_key} = ErrorInfo.ensure_key(error_info)
 
     error_storage_item =
       Agent.get(:boom_notifier, fn state -> state end)
@@ -96,7 +96,7 @@ defmodule BoomNotifier.ErrorStorage do
   """
   @spec reset_accumulated_errors(error_strategy, ErrorInfo.t()) :: :ok
   def reset_accumulated_errors(:exponential, error_info) do
-    error_hash_key = generate_error_key(error_info)
+    %{key: error_hash_key} = ErrorInfo.ensure_key(error_info)
 
     Agent.update(
       :boom_notifier,
@@ -108,7 +108,7 @@ defmodule BoomNotifier.ErrorStorage do
   end
 
   def reset_accumulated_errors([exponential: [limit: limit]], error_info) do
-    error_hash_key = generate_error_key(error_info)
+    %{key: error_hash_key} = ErrorInfo.ensure_key(error_info)
 
     Agent.update(
       :boom_notifier,
@@ -120,7 +120,7 @@ defmodule BoomNotifier.ErrorStorage do
   end
 
   def reset_accumulated_errors(:always, error_info) do
-    error_hash_key = generate_error_key(error_info)
+    %{key: error_hash_key} = ErrorInfo.ensure_key(error_info)
 
     Agent.update(
       :boom_notifier,
@@ -131,23 +131,6 @@ defmodule BoomNotifier.ErrorStorage do
     )
   end
 
-  # Generates a unique hash key based on the error info. The timestamp and the
-  # request info is removed so we don't get different keys for the same error.
-  #
-  # The map is converted to a string using `inspect()` so we can hash it using
-  # the crc32 algorithm that was taken from the Exception Notification library
-  # for Rails
-  @spec generate_error_key(ErrorInfo.t()) :: non_neg_integer()
-  def generate_error_key(error_info) do
-    error_info
-    |> Map.delete(:request)
-    |> Map.delete(:metadata)
-    |> Map.delete(:timestamp)
-    |> Map.update(:stack, nil, fn stacktrace -> List.first(stacktrace) end)
-    |> inspect()
-    |> :erlang.crc32()
-  end
-
   defp clear_values(error_storage_item) do
     error_storage_item
     |> Map.replace!(:accumulated_occurrences, 0)