Send async events right away without queueing

lib/sentry/client.ex

@@ -84,9 +84,7 @@ defmodule Sentry.Client do
   end
 
   defp encode_and_send(%Event{} = event, _result_type = :sync, request_retries) do
-    envelope = Envelope.new([event])
-
-    send_result = Transport.post_envelope(envelope, request_retries)
+    send_result = [event] |> Envelope.new() |> Transport.post_envelope(request_retries)
 
     if match?({:ok, _}, send_result) do
       Sentry.put_last_event_id_and_source(event.event_id, event.source)

lib/sentry/envelope.ex

@@ -13,10 +13,13 @@ defmodule Sentry.Envelope do
   defstruct [:event_id, :items]
 
   @doc """
-  Creates a new envelope containing the given events.
+  Creates a new envelope containing the given event.
+
+  Envelopes can only have a single element of type "event", so that's why we
+  restrict on a single-element list.
   """
   @spec new([Event.t(), ...]) :: t()
-  def new([%Event{event_id: event_id} | _rest] = events) do
+  def new([%Event{event_id: event_id}] = events) do
     %__MODULE__{
       event_id: event_id,
       items: events
@@ -25,36 +28,33 @@ defmodule Sentry.Envelope do
 
   @doc """
   Encodes the envelope into its binary representation.
+
+  For now, we support only envelopes with a single event in them.
   """
   @spec to_binary(t()) :: {:ok, binary()} | {:error, any()}
-  def to_binary(%__MODULE__{} = envelope) do
+  def to_binary(%__MODULE__{items: [%Event{} = event]} = envelope) do
     json_library = Config.json_library()
 
-    encoded_items =
-      Enum.map(envelope.items, fn item ->
-        case encode_item(item, json_library) do
-          {:ok, encoded_item} ->
-            type =
-              if is_struct(item, Event) do
-                "event"
-              else
-                raise "unexpected item in envelope: #{inspect(item)}"
-              end
-
-            [
-              ~s({"type": "#{type}", "length": #{byte_size(encoded_item)}}\n),
-              encoded_item,
-              ?\n
-            ]
-
-          {:error, _reason} = error ->
-            throw(error)
-        end
-      end)
-
-    {:ok, IO.iodata_to_binary([encode_headers(envelope) | encoded_items])}
-  catch
-    {:error, reason} -> {:error, reason}
+    headers_iodata =
+      case envelope.event_id do
+        nil -> "{{}}\n"
+        event_id -> ~s({"event_id":"#{event_id}"}\n)
+      end
+
+    case event |> Sentry.Client.render_event() |> json_library.encode() do
+      {:ok, encoded_event} ->
+        body = [
+          headers_iodata,
+          ~s({"type": "event", "length": #{byte_size(encoded_event)}}\n),
+          encoded_event,
+          ?\n
+        ]
+
+        {:ok, IO.iodata_to_binary(body)}
+
+      {:error, _reason} = error ->
+        error
+    end
   end
 
   @doc """
@@ -79,23 +79,6 @@ defmodule Sentry.Envelope do
     end
   end
 
-  #
-  # Encoding
-  #
-
-  defp encode_headers(%__MODULE__{} = envelope) do
-    case envelope.event_id do
-      nil -> "{{}}\n"
-      event_id -> ~s({"event_id":"#{event_id}"}\n)
-    end
-  end
-
-  defp encode_item(%Event{} = event, json_library) do
-    event
-    |> Sentry.Client.render_event()
-    |> json_library.encode()
-  end
-
   #
   # Decoding
   #

lib/sentry/transport/sender.ex

@@ -9,9 +9,6 @@ defmodule Sentry.Transport.Sender do
 
   @registry Sentry.Transport.SenderRegistry
 
-  @async_queue_max_size 10
-  @async_queue_timeout 500
-
   # This behaviour is only present for mocks in tests.
   defmodule Behaviour do
     @moduledoc false
@@ -39,54 +36,27 @@ defmodule Sentry.Transport.Sender do
 
   ## State
 
-  defstruct async_queue: :queue.new()
+  defstruct []
 
   ## Callbacks
 
   @impl GenServer
   def init([]) do
-    Process.send_after(self(), :flush_async_queue, @async_queue_timeout)
     {:ok, %__MODULE__{}}
   end
 
   @impl GenServer
   def handle_cast({:send, %Event{} = event}, %__MODULE__{} = state) do
-    state = update_in(state.async_queue, &:queue.in(event, &1))
-
-    state =
-      if :queue.len(state.async_queue) >= @async_queue_max_size do
-        flush_async_queue(state)
-      else
-        state
-      end
+    [event]
+    |> Envelope.new()
+    |> Transport.post_envelope()
+    |> maybe_log_send_result([event])
 
     {:noreply, state}
   end
 
-  @impl GenServer
-  def handle_info(:flush_async_queue, %__MODULE__{} = state) do
-    state = flush_async_queue(state)
-    Process.send_after(self(), :flush_async_queue, @async_queue_timeout)
-    {:noreply, state}
-  end
-
   ## Helpers
 
-  defp flush_async_queue(%__MODULE__{async_queue: events_queue} = state) do
-    if :queue.is_empty(events_queue) do
-      state
-    else
-      events = :queue.to_list(events_queue)
-
-      events
-      |> Envelope.new()
-      |> Transport.post_envelope()
-      |> maybe_log_send_result(events)
-
-      %__MODULE__{state | async_queue: :queue.new()}
-    end
-  end
-
   defp maybe_log_send_result(send_result, events) do
     if Enum.any?(events, &(&1.source == :logger)) do
       :ok

test/envelope_test.exs

@@ -71,8 +71,8 @@ defmodule Sentry.EnvelopeTest do
 
       {:ok, raw_envelope} =
         [event]
-        |> Sentry.Envelope.new()
-        |> Sentry.Envelope.to_binary()
+        |> Envelope.new()
+        |> Envelope.to_binary()
 
       {:ok, envelope} = Envelope.from_binary(raw_envelope)
 

test/sentry/transport_test.exs

@@ -15,9 +15,7 @@ defmodule Sentry.TransportTest do
     test "sends a POST request with the right headers and payload", %{bypass: bypass} do
       envelope =
         Envelope.new([
-          Event.create_event(message: "Hello 1"),
-          Event.create_event(message: "Hello 2"),
-          Event.create_event(message: "Hello 3")
+          Event.create_event(message: "Hello 1")
         ])
 
       Bypass.expect_once(bypass, fn conn ->