Send overflow metric for more cardinality errors (#8740)

Author: bonnici

.changesets/fix_njm_fix_cardinality_overflow_metric.md

@@ -0,0 +1,5 @@
+### Fix OTel cardinality overflow metric for more error strings ([PR #8740](https://github.com/apollographql/router/pull/8740))
+
+Emit the apollo.router.telemetry.metrics.cardinality_overflow metric for more instances where an OTel cardinality error has occurred. The message check has been changed to support a different form of the error that has been reported by a customer.
+
+By [@bonnici](https://github.com/bonnici) in https://github.com/apollographql/router/pull/8740

apollo-router/src/plugins/telemetry/error_handler.rs

@@ -61,8 +61,9 @@ fn handle_error_with_map<T: Into<opentelemetry::global::Error>>(
         // Keep track of the number of cardinality overflow errors otel emits. This can be removed after upgrading to 0.28.0 when the cardinality limit is removed.
         // The version upgrade will also cause this log to be removed from our visibility even if we were set up custom a cardinality limit.
         // https://github.com/open-telemetry/opentelemetry-rust/pull/2528
-        if err.to_string()
-            == "Metrics error: Warning: Maximum data points for metric stream exceeded. Entry added to overflow. Subsequent overflows to same metric until next collect will not be logged."
+        if err
+            .to_string()
+            .contains("Maximum data points for metric stream exceeded. Entry added to overflow.")
         {
             u64_counter!(
                 "apollo.router.telemetry.metrics.cardinality_overflow",
@@ -326,7 +327,7 @@ mod tests {
     }
 
     #[tokio::test]
-    async fn test_cardinality_overflow() {
+    async fn test_cardinality_overflow_1() {
         async {
             let error_map = DashMap::new();
             let msg = "Warning: Maximum data points for metric stream exceeded. Entry added to overflow. Subsequent overflows to same metric until next collect will not be logged.";
@@ -344,6 +345,25 @@ mod tests {
         .await;
     }
 
+    #[tokio::test]
+    async fn test_cardinality_overflow_2() {
+        async {
+            let error_map = DashMap::new();
+            let msg =
+                "Warning: Maximum data points for metric stream exceeded. Entry added to overflow.";
+            handle_error_with_map(
+                opentelemetry::global::Error::Metric(opentelemetry::metrics::MetricsError::Other(
+                    msg.to_string(),
+                )),
+                &error_map,
+            );
+
+            assert_counter!("apollo.router.telemetry.metrics.cardinality_overflow", 1);
+        }
+        .with_metrics()
+        .await;
+    }
+
     // Mock span exporter to test failures
     #[derive(Debug)]
     struct FailingSpanExporter;