feat(component validation): validate component_discarded_events_total for sources

src/components/validation/mod.rs

@@ -181,6 +181,7 @@ pub struct RunnerMetrics {
     pub sent_bytes_total: u64, // a reciprocal for received_bytes_total
     pub sent_event_bytes_total: u64,
     pub sent_events_total: u64,
+    pub discarded_events_total: u64,
 }
 
 #[cfg(all(test, feature = "component-validation-tests"))]

src/components/validation/validators/component_spec/sources.rs

@@ -14,6 +14,7 @@ pub enum SourceMetricType {
     ReceivedBytesTotal,
     SentEventsTotal,
     SentEventBytesTotal,
+    EventsDropped,
 }
 
 impl SourceMetricType {
@@ -24,6 +25,7 @@ impl SourceMetricType {
             SourceMetricType::ReceivedBytesTotal => "component_received_bytes_total",
             SourceMetricType::SentEventsTotal => "component_sent_events_total",
             SourceMetricType::SentEventBytesTotal => "component_sent_event_bytes_total",
+            SourceMetricType::EventsDropped => "component_discarded_events_total",
         }
     }
 }
@@ -47,6 +49,7 @@ pub fn validate_sources(
         validate_component_received_bytes_total,
         validate_component_sent_events_total,
         validate_component_sent_event_bytes_total,
+        validate_component_discarded_events_total,
     ];
 
     for v in validations.iter() {
@@ -226,3 +229,16 @@ fn validate_component_sent_event_bytes_total(
         expected_bytes,
     )
 }
+
+fn validate_component_discarded_events_total(
+    telemetry_events: &[Event],
+    runner_metrics: &RunnerMetrics,
+) -> Result<Vec<String>, Vec<String>> {
+    let expected_dropped = runner_metrics.discarded_events_total;
+
+    validate_bytes_total(
+        telemetry_events,
+        &SourceMetricType::EventsDropped,
+        expected_dropped,
+    )
+}