enhancement(tag_cardinality_limit transform): Add metric and tag name to tag_value_limit_exceeded_total metric

changelog.d/tag_cardinality_limit_metric_labels.enhancement.md

@@ -0,0 +1,3 @@
+The `tag_value_limit_exceeded_total` metric now includes `metric_name` and `tag_key` labels to help identify which specific metrics and tag keys are hitting the configured value limit in the `tag_cardinality_limit` transform.
+
+authors: kaarolch

src/internal_events/tag_cardinality_limit.rs

@@ -15,7 +15,12 @@ impl InternalEvent for TagCardinalityLimitRejectingEvent<'_> {
             tag_key = self.tag_key,
             tag_value = self.tag_value,
         );
-        counter!("tag_value_limit_exceeded_total").increment(1);
+        counter!(
+            "tag_value_limit_exceeded_total",
+            "metric_name" => self.metric_name.to_string(),
+            "tag_key" => self.tag_key.to_string(),
+        )
+        .increment(1);
 
         emit!(ComponentEventsDropped::<INTENTIONAL> {
             count: 1,
@@ -38,7 +43,12 @@ impl InternalEvent for TagCardinalityLimitRejectingTag<'_> {
             tag_key = self.tag_key,
             tag_value = self.tag_value,
         );
-        counter!("tag_value_limit_exceeded_total").increment(1);
+        counter!(
+            "tag_value_limit_exceeded_total",
+            "metric_name" => self.metric_name.to_string(),
+            "tag_key" => self.tag_key.to_string(),
+        )
+        .increment(1);
     }
 }
 

website/cue/reference/components/sources/internal_metrics.cue

@@ -776,7 +776,16 @@ components: sources: internal_metrics: {
 				"""
 			type:              "counter"
 			default_namespace: "vector"
-			tags:              _component_tags
+			tags: _component_tags & {
+				metric_name: {
+					description: "The name of the metric for which the tag value limit was exceeded."
+					required:    true
+				}
+				tag_key: {
+					description: "The key of the tag for which the value limit was exceeded."
+					required:    true
+				}
+			}
 		}
 		timestamp_parse_errors_total: {
 			description:       "The total number of errors encountered parsing [RFC 3339](\(urls.rfc_3339)) timestamps."