wip(metrics): add Metrics support

Author: solnic

lib/sentry.ex

@@ -234,6 +234,17 @@ defmodule Sentry do
           (Sentry.LogEvent.t() -> as_boolean(Sentry.LogEvent.t()))
           | {module(), function_name :: atom()}
 
+  @typedoc """
+  A callback to use with the `:before_send_metric` configuration option.
+
+  If this is `{module, function_name}`, then `module.function_name(metric)` will
+  be called, where `metric` is of type `t:Sentry.Metric.t/0`.
+  """
+  @typedoc since: "13.0.0"
+  @type before_send_metric_callback() ::
+          (Sentry.Metric.t() -> as_boolean(Sentry.Metric.t()))
+          | {module(), function_name :: atom()}
+
   @typedoc """
   The strategy to use when sending an event to Sentry.
   """

lib/sentry/client.ex

@@ -15,6 +15,7 @@ defmodule Sentry.Client do
     Event,
     Interfaces,
     LoggerUtils,
+    Metric,
     Options,
     TelemetryProcessor,
     Transaction,
@@ -144,6 +145,85 @@ defmodule Sentry.Client do
     end
   end
 
+  @spec send_metric(Metric.t()) :: :ok
+  def send_metric(%Metric{} = metric) do
+    result_type = Config.send_result()
+
+    case result_type do
+      :sync ->
+        case apply_before_send_metric(metric) do
+          [%Metric{} = filtered_metric] ->
+            case Sentry.Test.maybe_collect_metrics([filtered_metric]) do
+              :collected ->
+                :ok
+
+              :not_collecting ->
+                if Config.dsn() do
+                  client = Config.client()
+
+                  request_retries =
+                    Application.get_env(:sentry, :request_retries, Transport.default_retries())
+
+                  filtered_metric
+                  |> List.wrap()
+                  |> Envelope.from_metric_events()
+                  |> Transport.encode_and_post_envelope(client, request_retries)
+                end
+
+                :ok
+            end
+
+          [] ->
+            :ok
+        end
+
+      :none ->
+        # Buffered mode (production): add to TelemetryProcessor
+        if Config.telemetry_processor_category?(:metric) do
+          case TelemetryProcessor.add(metric) do
+            {:ok, {:rate_limited, data_category}} ->
+              ClientReport.Sender.record_discarded_events(:ratelimit_backoff, data_category)
+
+            :ok ->
+              :ok
+          end
+        end
+
+        :ok
+    end
+  end
+
+  defp apply_before_send_metric(metric) do
+    callback = Config.before_send_metric()
+
+    if callback do
+      case call_before_send_metric(metric, callback) do
+        %Metric{} = modified -> [modified]
+        _ -> []
+      end
+    else
+      [metric]
+    end
+  end
+
+  defp call_before_send_metric(metric, function) when is_function(function, 1) do
+    function.(metric)
+  rescue
+    error ->
+      require Logger
+      Logger.warning("before_send_metric callback failed: #{inspect(error)}")
+      metric
+  end
+
+  defp call_before_send_metric(metric, {mod, fun}) do
+    apply(mod, fun, [metric])
+  rescue
+    error ->
+      require Logger
+      Logger.warning("before_send_metric callback failed: #{inspect(error)}")
+      metric
+  end
+
   defp sample_event(sample_rate) do
     cond do
       sample_rate == 1 -> :ok

lib/sentry/config.ex

@@ -396,6 +396,17 @@ defmodule Sentry.Config do
       *Available since 12.0.0*.
       """
     ],
+    enable_metrics: [
+      type: :boolean,
+      default: true,
+      doc: """
+      Whether to enable sending metric events to Sentry. When enabled, the SDK will
+      capture and send metrics (counters, gauges, distributions) according to the
+      [Sentry Metrics Protocol](https://develop.sentry.dev/sdk/telemetry/metrics/).
+      Use `Sentry.Metrics` functions to record metrics.
+      *Available since 13.0.0*.
+      """
+    ],
     logs: [
       type: :keyword_list,
       default: [],
@@ -434,8 +445,8 @@ defmodule Sentry.Config do
       ]
     ],
     telemetry_processor_categories: [
-      type: {:list, {:in, [:error, :check_in, :transaction, :log]}},
-      default: [:log],
+      type: {:list, {:in, [:error, :check_in, :transaction, :log, :metric]}},
+      default: [:log, :metric],
       doc: """
       List of event categories that should be processed through the TelemetryProcessor.
       Categories in this list use the TelemetryProcessor's ring buffer and weighted
@@ -447,6 +458,7 @@ defmodule Sentry.Config do
         * `:check_in` - Cron check-ins (high priority, batch_size=1)
         * `:transaction` - Performance transactions (medium priority, batch_size=1)
         * `:log` - Log entries (low priority, batch_size=100, 5s timeout)
+        * `:metric` - Metric events (low priority, batch_size=100, 5s timeout)
 
       *Available since 12.0.0*.
       """
@@ -702,6 +714,17 @@ defmodule Sentry.Config do
       (potentially-updated) `Sentry.LogEvent`, then the updated log event is used instead.
       *Available since v12.0.0*.
       """
+    ],
+    before_send_metric: [
+      type: {:or, [nil, {:fun, 1}, {:tuple, [:atom, :atom]}]},
+      type_doc: "`t:before_send_metric_callback/0`",
+      doc: """
+      Allows performing operations on a metric *before* it is sent, as
+      well as filtering out the metric altogether.
+      If the callback returns `nil` or `false`, the metric is not reported. If it returns a
+      (potentially-updated) `Sentry.Metric`, then the updated metric is used instead.
+      *Available since v13.0.0*.
+      """
     ]
   ]
 
@@ -905,6 +928,9 @@ defmodule Sentry.Config do
   @spec enable_logs?() :: boolean()
   def enable_logs?, do: fetch!(:enable_logs)
 
+  @spec enable_metrics?() :: boolean()
+  def enable_metrics?, do: fetch!(:enable_metrics)
+
   @spec logs() :: keyword()
   def logs, do: fetch!(:logs)
 
@@ -937,6 +963,10 @@ defmodule Sentry.Config do
           (Sentry.LogEvent.t() -> Sentry.LogEvent.t() | nil | false) | {module(), atom()} | nil
   def before_send_log, do: get(:before_send_log)
 
+  @spec before_send_metric() ::
+          (Sentry.Metric.t() -> Sentry.Metric.t() | nil | false) | {module(), atom()} | nil
+  def before_send_metric, do: get(:before_send_metric)
+
   @spec put_config(atom(), term()) :: :ok
   def put_config(key, value) when is_atom(key) do
     unless key in @valid_keys do

lib/sentry/envelope.ex

@@ -10,6 +10,8 @@ defmodule Sentry.Envelope do
     Event,
     LogBatch,
     LogEvent,
+    Metric,
+    MetricBatch,
     Transaction,
     UUID
   }
@@ -22,6 +24,7 @@ defmodule Sentry.Envelope do
             | ClientReport.t()
             | Event.t()
             | LogBatch.t()
+            | MetricBatch.t()
             | Transaction.t(),
             ...
           ]
@@ -94,6 +97,25 @@ defmodule Sentry.Envelope do
     }
   end
 
+  @doc """
+  Creates a new envelope containing metric events.
+
+  According to the Sentry Metrics Protocol, metrics are sent in batches
+  within a single envelope item with content type `application/vnd.sentry.items.trace-metric+json`.
+  All metric events are wrapped in a single item with `{ items: [...] }`.
+  """
+  @doc since: "13.0.0"
+  @spec from_metric_events([Metric.t()]) :: t()
+  def from_metric_events(metrics) when is_list(metrics) do
+    # Create a single metric batch item that wraps all metrics
+    metric_batch = %MetricBatch{metrics: metrics}
+
+    %__MODULE__{
+      event_id: UUID.uuid4_hex(),
+      items: [metric_batch]
+    }
+  end
+
   @doc """
   Returns the "data category" of the envelope's contents (to be used in client reports and more).
   """
@@ -104,6 +126,7 @@ defmodule Sentry.Envelope do
           | ClientReport.t()
           | Event.t()
           | LogBatch.t()
+          | MetricBatch.t()
           | Transaction.t()
         ) ::
           String.t()
@@ -113,17 +136,19 @@ defmodule Sentry.Envelope do
   def get_data_category(%ClientReport{}), do: "internal"
   def get_data_category(%Event{}), do: "error"
   def get_data_category(%LogBatch{}), do: "log_item"
+  def get_data_category(%MetricBatch{}), do: "trace_metric"
 
   @doc """
   Returns the total number of payload items in the envelope.
 
-  For log envelopes, this counts individual log events within the LogBatch.
+  For log and metric envelopes, this counts individual items within the batch.
   For other envelope types, each item counts as 1.
   """
   @spec item_count(t()) :: non_neg_integer()
   def item_count(%__MODULE__{items: items}) do
     Enum.reduce(items, 0, fn
       %LogBatch{log_events: log_events}, acc -> acc + length(log_events)
+      %MetricBatch{metrics: metrics}, acc -> acc + length(metrics)
       _other, acc -> acc + 1
     end)
   end
@@ -228,4 +253,24 @@ defmodule Sentry.Envelope do
         throw(error)
     end
   end
+
+  defp item_to_binary(json_library, %MetricBatch{metrics: metrics}) do
+    items = Enum.map(metrics, &Metric.to_map/1)
+    payload = %{items: items}
+
+    case Sentry.JSON.encode(payload, json_library) do
+      {:ok, encoded_payload} ->
+        header = %{
+          "type" => "trace_metric",
+          "item_count" => length(items),
+          "content_type" => "application/vnd.sentry.items.trace-metric+json"
+        }
+
+        {:ok, encoded_header} = Sentry.JSON.encode(header, json_library)
+        [encoded_header, ?\n, encoded_payload, ?\n]
+
+      {:error, _reason} = error ->
+        throw(error)
+    end
+  end
 end