[exporterhelper] Add exporter dropped metrics

.chloggen/exporter-dropped-metric.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: exporterhelper
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Adds `exporter_dropped_spans`, `exporter_dropped_metric_points`, and `exporter_dropped_log_records` to record when an exporter has dropped data forever.
+
+# One or more tracking issues or pull requests related to the change
+issues: [11077]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

exporter/exporterhelper/documentation.md

@@ -6,6 +6,30 @@
 
 The following telemetry is emitted by this component.
 
+### otelcol_exporter_dropped_log_records
+
+Number of log records dropped after failing to export.
+
+| Unit | Metric Type | Value Type | Monotonic |
+| ---- | ----------- | ---------- | --------- |
+| {records} | Sum | Int | true |
+
+### otelcol_exporter_dropped_metric_points
+
+Number of metric points dropped after failing to export.
+
+| Unit | Metric Type | Value Type | Monotonic |
+| ---- | ----------- | ---------- | --------- |
+| {datapoints} | Sum | Int | true |
+
+### otelcol_exporter_dropped_spans
+
+Number of spans dropped after failing to export.
+
+| Unit | Metric Type | Value Type | Monotonic |
+| ---- | ----------- | ---------- | --------- |
+| {spans} | Sum | Int | true |
+
 ### otelcol_exporter_enqueue_failed_log_records
 
 Number of log records failed to be added to the sending queue.

exporter/exporterhelper/internal/base_exporter.go

@@ -136,6 +136,7 @@ func NewBaseExporter(set exporter.Settings, signal component.DataType, osf Obsre
 func (be *BaseExporter) Send(ctx context.Context, req internal.Request) error {
 	err := be.QueueSender.Send(ctx, req)
 	if err != nil {
+		recordDroppedMetric(ctx, be.Obsrep, int64(req.ItemsCount()))
 		be.Set.Logger.Error("Exporting failed. Rejecting data."+be.ExportFailureMessage,
 			zap.Error(err), zap.Int("rejected_items", req.ItemsCount()))
 	}
@@ -339,3 +340,15 @@ func CheckStatus(t *testing.T, sd sdktrace.ReadOnlySpan, err error) {
 		require.Equal(t, codes.Unset, sd.Status().Code, "SpanData %v", sd)
 	}
 }
+
+func recordDroppedMetric(ctx context.Context, obsrep *ObsReport, count int64) {
+	if obsrep.DataType == component.DataTypeTraces {
+		obsrep.TelemetryBuilder.ExporterDroppedSpans.Add(ctx, count)
+	}
+	if obsrep.DataType == component.DataTypeMetrics {
+		obsrep.TelemetryBuilder.ExporterDroppedMetricPoints.Add(ctx, count)
+	}
+	if obsrep.DataType == component.DataTypeLogs {
+		obsrep.TelemetryBuilder.ExporterDroppedLogRecords.Add(ctx, count)
+	}
+}

exporter/exporterhelper/internal/queue_sender.go

@@ -97,6 +97,7 @@ func NewQueueSender(q exporterqueue.Queue[internal.Request], set exporter.Settin
 	consumeFunc := func(ctx context.Context, req internal.Request) error {
 		err := qs.NextSender.Send(ctx, req)
 		if err != nil {
+			recordDroppedMetric(ctx, qs.obsrep, int64(req.ItemsCount()))
 			set.Logger.Error("Exporting failed. Dropping data."+exportFailureMessage,
 				zap.Error(err), zap.Int("dropped_items", req.ItemsCount()))
 		}

exporter/exporterhelper/metadata.yaml

@@ -99,3 +99,27 @@ telemetry:
       gauge:
         value_type: int
         async: true
+
+    exporter_dropped_spans:
+      enabled: true
+      description: Number of spans dropped after failing to export.
+      unit: "{spans}"
+      sum:
+        value_type: int
+        monotonic: true
+
+    exporter_dropped_metric_points:
+      enabled: true
+      description: Number of metric points dropped after failing to export.
+      unit: "{datapoints}"
+      sum:
+        value_type: int
+        monotonic: true
+
+    exporter_dropped_log_records:
+      enabled: true
+      description: Number of log records dropped after failing to export.
+      unit: "{records}"
+      sum:
+        value_type: int
+        monotonic: true