chore(instrumentation-mongodb): update metric names to semconv METRIC_* exports (#3127)

Author: trentm

packages/instrumentation-mongodb/src/instrumentation.ts

@@ -37,6 +37,7 @@ import {
   ATTR_NET_PEER_NAME,
   ATTR_NET_PEER_PORT,
   DB_SYSTEM_VALUE_MONGODB,
+  METRIC_DB_CLIENT_CONNECTIONS_USAGE,
 } from './semconv';
 import { MongoDBInstrumentationConfig, CommandResult } from './types';
 import {
@@ -74,7 +75,7 @@ export class MongoDBInstrumentation extends InstrumentationBase<MongoDBInstrumen
 
   override _updateMetricInstruments() {
     this._connectionsUsage = this.meter.createUpDownCounter(
-      'db.client.connections.usage',
+      METRIC_DB_CLIENT_CONNECTIONS_USAGE,
       {
         description:
           'The number of connections that are currently in state described by the state attribute.',

packages/instrumentation-mongodb/src/semconv.ts

@@ -118,3 +118,13 @@ export const ATTR_NET_PEER_PORT = 'net.peer.port' as const;
  * @experimental This enum value is experimental and is subject to breaking changes in minor releases of `@opentelemetry/semantic-conventions`.
  */
 export const DB_SYSTEM_VALUE_MONGODB = 'mongodb' as const;
+
+/**
+ * Deprecated, use `db.client.connection.count` instead.
+ *
+ * @experimental This metric is experimental and is subject to breaking changes in minor releases of `@opentelemetry/semantic-conventions`.
+ *
+ * @deprecated Replaced by `db.client.connection.count`.
+ */
+export const METRIC_DB_CLIENT_CONNECTIONS_USAGE =
+  'db.client.connections.usage' as const;