feat: support batching (#66)

Can't add tests now since batching is a cloud only feature at the
moment.
Will need to come back and add it once extracted out into OSS

---------

Co-authored-by: Darwin D Wu <darwin67@users.noreply.github.com>

.github/workflows/ci.yml

@@ -17,6 +17,7 @@ jobs:
     name: Test (Elixir ${{ matrix.elixir }} / OTP ${{ matrix.otp }})
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
         # NOTE: best effort coverage
         # https://hexdocs.pm/elixir/compatibility-and-deprecations.html#compatibility-between-elixir-and-erlang-otp

lib/inngest/error.ex

@@ -9,3 +9,7 @@ end
 defmodule Inngest.InvalidDebounceConfigError do
   defexception message: "a 'period' must be set for debounce"
 end
+
+defmodule Inngest.InvalidBatchEventConfigError do
+  defexception [:message]
+end

lib/inngest/function.ex

@@ -87,22 +87,16 @@ defmodule Inngest.Function do
       )
 
       @behaviour Inngest.Function
-      @default_retries 3
 
       @impl true
       def slug() do
-        __MODULE__.__info__(:attributes)
-        |> Keyword.get(:func)
-        |> List.first()
+        fn_opts()
         |> Map.get(:id)
       end
 
       @impl true
       def name() do
-        case __MODULE__.__info__(:attributes)
-             |> Keyword.get(:func)
-             |> List.first()
-             |> Map.get(:name) do
+        case fn_opts() |> Map.get(:name) do
           nil -> slug()
           name -> name
         end
@@ -116,13 +110,13 @@ defmodule Inngest.Function do
       end
 
       def slugs() do
-        failure = if failure_handler_defined?(__MODULE__), do: [failure_slug()], else: []
+        failure = if failure_handler_defined?(), do: [failure_slug()], else: []
         [slug()] ++ failure
       end
 
       def serve(path) do
         handler =
-          if failure_handler_defined?(__MODULE__) do
+          if failure_handler_defined?() do
             id = failure_slug()
 
             [
@@ -172,38 +166,31 @@ defmodule Inngest.Function do
             }
           }
           |> maybe_debounce()
+          |> maybe_batch_events()
         ] ++ handler
       end
 
-      defp retries() do
-        case __MODULE__.__info__(:attributes)
-             |> Keyword.get(:func)
-             |> List.first()
-             |> Map.get(:retries) do
-          nil -> @default_retries
-          retry -> retry
-        end
-      end
+      defp retries(), do: fn_opts() |> Map.get(:retries)
 
       defp maybe_debounce(config) do
-        case __MODULE__.__info__(:attributes)
-             |> Keyword.get(:func)
-             |> List.first()
-             |> Map.get(:debounce) do
-          nil ->
-            config
-
-          debounce ->
-            if Map.get(debounce, :period) == nil do
-              raise Inngest.InvalidDebounceConfigError
-            else
-              Map.put(config, :debounce, debounce)
-            end
+        fn_opts()
+        |> Inngest.FnOpts.validate_debounce(config)
+      end
+
+      defp maybe_batch_events(config) do
+        fn_opts()
+        |> Inngest.FnOpts.validate_batch_events(config)
+      end
+
+      defp fn_opts() do
+        case __MODULE__.__info__(:attributes) |> Keyword.get(:func) |> List.first() do
+          nil -> %Inngest.FnOpts{}
+          val -> val
         end
       end
 
-      defp failure_handler_defined?(mod) do
-        mod.__info__(:functions) |> Keyword.get(:handle_failure) == 2
+      defp failure_handler_defined?() do
+        __MODULE__.__info__(:functions) |> Keyword.get(:handle_failure) == 2
       end
 
       defp failure_slug(), do: "#{slug()}-failure"
@@ -246,26 +233,3 @@ defmodule Inngest.Function do
 
   def validate_datetime(_), do: {:error, "Expect valid DateTime formatted input"}
 end
-
-defmodule Inngest.FnOpts do
-  @moduledoc false
-
-  defstruct [
-    :id,
-    :name,
-    :retries,
-    :debounce
-  ]
-
-  @type t() :: %__MODULE__{
-          id: binary(),
-          name: binary(),
-          retries: number() | nil,
-          debounce: debounce() | nil
-        }
-
-  @type debounce() :: %{
-          key: nil | binary(),
-          period: binary()
-        }
-end

lib/inngest/function/config.ex

@@ -0,0 +1,103 @@
+defmodule Inngest.FnOpts do
+  @moduledoc false
+
+  defstruct [
+    :id,
+    :name,
+    :debounce,
+    :batch_events,
+    retries: 3
+  ]
+
+  alias Inngest.Util
+
+  @type t() :: %__MODULE__{
+          id: binary(),
+          name: binary(),
+          retries: number() | nil,
+          debounce: debounce() | nil,
+          batch_events: batch_events() | nil
+        }
+
+  @type debounce() :: %{
+          key: nil | binary(),
+          period: binary()
+        }
+
+  @type batch_events() :: %{
+          max_size: number(),
+          timeout: binary()
+        }
+
+  @doc """
+  Validate the debounce configuration
+  """
+  @spec validate_debounce(t(), map()) :: map()
+  def validate_debounce(fnopts, config) do
+    case fnopts |> Map.get(:debounce) do
+      nil ->
+        config
+
+      debounce ->
+        period = Map.get(debounce, :period)
+
+        if is_nil(period) do
+          raise Inngest.InvalidDebounceConfigError
+        end
+
+        case Util.parse_duration(period) do
+          {:error, error} ->
+            raise Inngest.InvalidDebounceConfigError, message: error
+
+          {:ok, seconds} ->
+            # credo:disable-for-next-line
+            if seconds > 7 * Util.day_in_seconds() do
+              raise Inngest.InvalidDebounceConfigError,
+                message: "cannot specify period for more than 7 days"
+            end
+        end
+
+        Map.put(config, :debounce, debounce)
+    end
+  end
+
+  @doc """
+  Validate the event batch config
+  """
+  @spec validate_batch_events(t(), map()) :: map()
+  def validate_batch_events(fnopts, config) do
+    case fnopts |> Map.get(:batch_events) do
+      nil ->
+        config
+
+      batch ->
+        max_size = Map.get(batch, :max_size)
+        timeout = Map.get(batch, :timeout)
+
+        if is_nil(max_size) do
+          raise Inngest.InvalidBatchEventConfigError,
+            message: "'max_size' must be set for batch_events"
+        end
+
+        if is_nil(timeout) do
+          raise Inngest.InvalidBatchEventConfigError,
+            message: "'timeout' must be set for batch_events"
+        end
+
+        case Util.parse_duration(timeout) do
+          {:error, error} ->
+            raise Inngest.InvalidBatchEventConfigError, message: error
+
+          {:ok, seconds} ->
+            # credo:disable-for-next-line
+            if seconds < 1 || seconds > 60 do
+              raise Inngest.InvalidBatchEventConfigError,
+                message: "'timeout' duration set to '#{timeout}', needs to be 1s - 60s"
+            end
+        end
+
+        batch = batch |> Map.put(:maxSize, max_size) |> Map.drop([:max_size])
+        Map.put(config, :batchEvents, batch)
+    end
+  end
+end

lib/inngest/util.ex

@@ -0,0 +1,32 @@
+defmodule Inngest.Util do
+  @moduledoc """
+  Utility functions
+  """
+
+  @doc """
+  Parse string duration that Inngest understands into seconds
+  """
+  @spec parse_duration(binary()) :: {:ok, number()} | {:error, binary()}
+  def parse_duration(value) do
+    with [_, num, unit] <- Regex.run(~r/(\d+)(s|m|h|d)/i, value),
+         dur <- String.to_integer(num) do
+      case unit do
+        "d" -> {:ok, dur * day_in_seconds()}
+        "h" -> {:ok, dur * hour_in_seconds()}
+        "m" -> {:ok, dur * minute_in_seconds()}
+        "s" -> {:ok, dur}
+        _ -> {:error, "invalid time unit '#{unit}', must be d|h|m|s"}
+      end
+    else
+      nil ->
+        {:error, "invalid duration: '#{value}'"}
+
+      _ ->
+        {:error, "unknow error occurred when parsing duration"}
+    end
+  end
+
+  def day_in_seconds(), do: 60 * 60 * 24
+  def hour_in_seconds(), do: 60 * 60
+  def minute_in_seconds(), do: 60
+end

test/inngest/function/cases/batch_events_test.exs

@@ -0,0 +1,8 @@
+defmodule Inngest.Function.Cases.BatchEventsTest do
+  use ExUnit.Case, async: true
+
+  alias Inngest.Test.DevServer
+  import Inngest.Test.Helper
+
+  # TODO: Add test after moving batching logic to OSS
+end