fix(sdk-metrics-base): metrics name should be in the max length of 63 (#2495)

Co-authored-by: Bartlomiej Obecny <[email protected]>
Co-authored-by: Valentin Marchaud <[email protected]>

Author: 3 people

experimental/packages/opentelemetry-sdk-metrics-base/src/Meter.ts

@@ -350,6 +350,6 @@ export class Meter implements api.Meter {
    * @param name Name of metric to be created
    */
   private _isValidName(name: string): boolean {
-    return Boolean(name.match(/^[a-z][a-z0-9_.-]*$/i));
+    return Boolean(name.match(/^[a-z][a-z0-9_.-]{0,62}$/i));
   }
 }

experimental/packages/opentelemetry-sdk-metrics-base/test/Meter.test.ts

@@ -295,6 +295,13 @@ describe('Meter', () => {
         const counter = meter.createCounter('name with invalid characters^&*(');
         assert.ok(counter instanceof api.NoopMetric);
       });
+
+      it('should return no op metric if name exceeded length of 63', () => {
+        const counter = meter.createCounter('a'.repeat(63));
+        assert.ok(counter instanceof CounterMetric);
+        const counter2 = meter.createCounter('a'.repeat(64));
+        assert.ok(counter2 instanceof api.NoopMetric);
+      });
     });
   });