perf(NODE-5854): Conditional logger instantiation and precompute willLog perf fix

src/cmap/connection.ts

@@ -280,7 +280,7 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
       (this.monitorCommands ||
         (this.established &&
           !this.authContext?.reauthenticating &&
-          this.mongoLogger?.willLog(SeverityLevel.DEBUG, MongoLoggableComponent.COMMAND))) ??
+          this.mongoLogger?.willLog(MongoLoggableComponent.COMMAND, SeverityLevel.DEBUG))) ??
       false
     );
   }

src/cmap/connection_pool.ts

@@ -251,7 +251,7 @@ export class ConnectionPool extends TypedEventEmitter<ConnectionPoolEvents> {
     this[kMetrics] = new ConnectionPoolMetrics();
     this[kProcessingWaitQueue] = false;
 
-    this.mongoLogger = this[kServer].topology.client.mongoLogger;
+    this.mongoLogger = this[kServer].topology.client?.mongoLogger;
     this.component = 'connection';
 
     process.nextTick(() => {

src/mongo_client.ts

@@ -25,7 +25,8 @@ import {
   type LogComponentSeveritiesClientOptions,
   type MongoDBLogWritable,
   MongoLogger,
-  type MongoLoggerOptions
+  type MongoLoggerOptions,
+  SeverityLevel
 } from './mongo_logger';
 import { TypedEventEmitter } from './mongo_types';
 import { executeOperation } from './operations/execute_operation';
@@ -345,7 +346,7 @@ export class MongoClient extends TypedEventEmitter<MongoClientEvents> {
   /** @internal */
   topology?: Topology;
   /** @internal */
-  override readonly mongoLogger: MongoLogger;
+  override readonly mongoLogger: MongoLogger | undefined;
   /** @internal */
   private connectionLock?: Promise<this>;
 
@@ -359,7 +360,13 @@ export class MongoClient extends TypedEventEmitter<MongoClientEvents> {
     super();
 
     this[kOptions] = parseOptions(url, this, options);
-    this.mongoLogger = new MongoLogger(this[kOptions].mongoLoggerOptions);
+
+    const shouldSetLogger = Object.values(
+      this[kOptions].mongoLoggerOptions.componentSeverities
+    ).some(value => value !== SeverityLevel.OFF);
+    this.mongoLogger = shouldSetLogger
+      ? new MongoLogger(this[kOptions].mongoLoggerOptions)
+      : undefined;
 
     // eslint-disable-next-line @typescript-eslint/no-this-alias
     const client = this;
@@ -405,9 +412,9 @@ export class MongoClient extends TypedEventEmitter<MongoClientEvents> {
     const srvHostIsCosmosDB = isHostMatch(COSMOS_DB_CHECK, this[kOptions].srvHost);
 
     if (documentDBHostnames.length !== 0 || srvHostIsDocumentDB) {
-      this.mongoLogger.info('client', DOCUMENT_DB_MSG);
+      this.mongoLogger?.info('client', DOCUMENT_DB_MSG);
     } else if (cosmosDBHostnames.length !== 0 || srvHostIsCosmosDB) {
-      this.mongoLogger.info('client', COSMOS_DB_MSG);
+      this.mongoLogger?.info('client', COSMOS_DB_MSG);
     }
   }
 

src/mongo_logger.ts

@@ -728,6 +728,7 @@ export class MongoLogger {
   logDestination: MongoDBLogWritable;
   logDestinationIsStdErr: boolean;
   pendingLog: PromiseLike<unknown> | unknown = null;
+  private severities: Record<MongoLoggableComponent, Record<SeverityLevel, boolean>>;
 
   /**
    * This method should be used when logging errors that do not have a public driver API for
@@ -760,15 +761,27 @@ export class MongoLogger {
     this.maxDocumentLength = options.maxDocumentLength;
     this.logDestination = options.logDestination;
     this.logDestinationIsStdErr = options.logDestinationIsStdErr;
+    this.severities = this.createLoggingSeverities();
   }
 
-  willLog(severity: SeverityLevel, component: MongoLoggableComponent): boolean {
-    return compareSeverity(severity, this.componentSeverities[component]) <= 0;
+  createLoggingSeverities(): Record<MongoLoggableComponent, Record<SeverityLevel, boolean>> {
+    const severities = Object();
+    for (const component of Object.values(MongoLoggableComponent)) {
+      severities[component] = {};
+      for (const severityLevel of Object.values(SeverityLevel)) {
+        severities[component][severityLevel] =
+          compareSeverity(severityLevel, this.componentSeverities[component]) <= 0;
+      }
+    }
+    return severities;
   }
 
   turnOffSeverities() {
-    for (const key of Object.values(MongoLoggableComponent)) {
-      this.componentSeverities[key as MongoLoggableComponent] = SeverityLevel.OFF;
+    for (const component of Object.values(MongoLoggableComponent)) {
+      this.componentSeverities[component] = SeverityLevel.OFF;
+      for (const severityLevel of Object.values(SeverityLevel)) {
+        this.severities[component][severityLevel] = false;
+      }
     }
   }
 
@@ -797,12 +810,17 @@ export class MongoLogger {
     this.pendingLog = null;
   }
 
+  willLog(component: MongoLoggableComponent, severity: SeverityLevel): boolean {
+    if (severity === SeverityLevel.OFF) return false;
+    return this.severities[component][severity];
+  }
+
   private log(
     severity: SeverityLevel,
     component: MongoLoggableComponent,
     message: Loggable | string
   ): void {
-    if (!this.willLog(severity, component)) return;
+    if (!this.willLog(component, severity)) return;
 
     let logMessage: Log = { t: new Date(), c: component, s: severity };
     if (typeof message === 'string') {

src/sdam/monitor.ts

@@ -120,7 +120,7 @@ export class Monitor extends TypedEventEmitter<MonitorEvents> {
       serverMonitoringMode: options.serverMonitoringMode
     });
     this.isRunningInFaasEnv = getFAASEnv() != null;
-    this.mongoLogger = this[kServer].topology.client.mongoLogger;
+    this.mongoLogger = this[kServer].topology.client?.mongoLogger;
 
     const cancellationToken = this[kCancellationToken];
     // TODO: refactor this to pull it directly from the pool, requires new ConnectionPool integration

src/sdam/topology.ts

@@ -102,7 +102,7 @@ export type ServerSelectionCallback = Callback<Server>;
 export interface ServerSelectionRequest {
   serverSelector: ServerSelector;
   topologyDescription: TopologyDescription;
-  mongoLogger: MongoLogger;
+  mongoLogger: MongoLogger | undefined;
   transaction?: Transaction;
   startTime: number;
   callback: ServerSelectionCallback;
@@ -568,7 +568,7 @@ export class Topology extends TypedEventEmitter<TopologyEvents> {
     }
 
     options = { serverSelectionTimeoutMS: this.s.serverSelectionTimeoutMS, ...options };
-    this.client.mongoLogger.debug(
+    this.client.mongoLogger?.debug(
       MongoLoggableComponent.SERVER_SELECTION,
       new ServerSelectionStartedEvent(selector, this.description, options.operationName)
     );
@@ -578,7 +578,7 @@ export class Topology extends TypedEventEmitter<TopologyEvents> {
     const transaction = session && session.transaction;
 
     if (isSharded && transaction && transaction.server) {
-      this.client.mongoLogger.debug(
+      this.client.mongoLogger?.debug(
         MongoLoggableComponent.SERVER_SELECTION,
         new ServerSelectionSucceededEvent(
           selector,
@@ -611,7 +611,7 @@ export class Topology extends TypedEventEmitter<TopologyEvents> {
         `Server selection timed out after ${options.serverSelectionTimeoutMS} ms`,
         this.description
       );
-      this.client.mongoLogger.debug(
+      this.client.mongoLogger?.debug(
         MongoLoggableComponent.SERVER_SELECTION,
         new ServerSelectionFailedEvent(
           selector,
@@ -896,7 +896,7 @@ function drainWaitQueue(queue: List<ServerSelectionRequest>, err?: MongoDriverEr
 
     if (!waitQueueMember[kCancelled]) {
       if (err) {
-        waitQueueMember.mongoLogger.debug(
+        waitQueueMember.mongoLogger?.debug(
           MongoLoggableComponent.SERVER_SELECTION,
           new ServerSelectionFailedEvent(
             waitQueueMember.serverSelector,
@@ -943,7 +943,7 @@ function processWaitQueue(topology: Topology) {
         : serverDescriptions;
     } catch (e) {
       waitQueueMember.timeoutController.clear();
-      topology.client.mongoLogger.debug(
+      topology.client.mongoLogger?.debug(
         MongoLoggableComponent.SERVER_SELECTION,
         new ServerSelectionFailedEvent(
           waitQueueMember.serverSelector,
@@ -959,7 +959,7 @@ function processWaitQueue(topology: Topology) {
     let selectedServer: Server | undefined;
     if (selectedDescriptions.length === 0) {
       if (!waitQueueMember.waitingLogged) {
-        topology.client.mongoLogger.info(
+        topology.client.mongoLogger?.info(
           MongoLoggableComponent.SERVER_SELECTION,
           new WaitingForSuitableServerEvent(
             waitQueueMember.serverSelector,
@@ -992,7 +992,7 @@ function processWaitQueue(topology: Topology) {
         'server selection returned a server description but the server was not found in the topology',
         topology.description
       );
-      topology.client.mongoLogger.debug(
+      topology.client.mongoLogger?.debug(
         MongoLoggableComponent.SERVER_SELECTION,
         new ServerSelectionFailedEvent(
           waitQueueMember.serverSelector,
@@ -1011,7 +1011,7 @@ function processWaitQueue(topology: Topology) {
 
     waitQueueMember.timeoutController.clear();
 
-    topology.client.mongoLogger.debug(
+    topology.client.mongoLogger?.debug(
       MongoLoggableComponent.SERVER_SELECTION,
       new ServerSelectionSucceededEvent(
         waitQueueMember.serverSelector,

test/integration/node-specific/feature_flags.test.ts

@@ -1,6 +1,6 @@
 import { expect } from 'chai';
 
-import { MongoClient, type MongoLoggableComponent, SeverityLevel } from '../../mongodb';
+import { MongoClient, SeverityLevel } from '../../mongodb';
 
 describe('Feature Flags', () => {
   describe('@@mdb.skipPingOnConnect', () => {
@@ -45,16 +45,10 @@ describe('Feature Flags', () => {
     }
   });
 
+  // TODO(NODE-5672): Release Standardized Logger
   describe('@@mdb.enableMongoLogger', () => {
     let cachedEnv;
     const loggerFeatureFlag = Symbol.for('@@mdb.enableMongoLogger');
-    const components: Array<MongoLoggableComponent | 'default'> = [
-      'default',
-      'topology',
-      'serverSelection',
-      'connection',
-      'command'
-    ];
 
     before(() => {
       cachedEnv = process.env;
@@ -74,7 +68,7 @@ describe('Feature Flags', () => {
           const client = new MongoClient('mongodb://localhost:27017', {
             [loggerFeatureFlag]: true
           });
-          expect(client.mongoLogger.componentSeverities).to.have.property(
+          expect(client.mongoLogger?.componentSeverities).to.have.property(
             'command',
             SeverityLevel.EMERGENCY
           );
@@ -86,16 +80,11 @@ describe('Feature Flags', () => {
           process.env = {};
         });
 
-        it('does not enable logging for any component', () => {
+        it('does not create logger', () => {
           const client = new MongoClient('mongodb://localhost:27017', {
             [loggerFeatureFlag]: true
           });
-          for (const component of components) {
-            expect(client.mongoLogger.componentSeverities).to.have.property(
-              component,
-              SeverityLevel.OFF
-            );
-          }
+          expect(client.mongoLogger).to.not.exist;
         });
       });
     });
@@ -107,16 +96,11 @@ describe('Feature Flags', () => {
             process.env['MONGODB_LOG_COMMAND'] = SeverityLevel.EMERGENCY;
           });
 
-          it('does not enable logging', () => {
+          it('does not instantiate logger', () => {
             const client = new MongoClient('mongodb://localhost:27017', {
               [loggerFeatureFlag]: featureFlagValue
             });
-            for (const component of components) {
-              expect(client.mongoLogger.componentSeverities).to.have.property(
-                component,
-                SeverityLevel.OFF
-              );
-            }
+            expect(client.mongoLogger).to.not.exist;
           });
         });
 
@@ -125,16 +109,11 @@ describe('Feature Flags', () => {
             process.env = {};
           });
 
-          it('does not enable logging', () => {
+          it('does not instantiate logger', () => {
             const client = new MongoClient('mongodb://localhost:27017', {
               [loggerFeatureFlag]: featureFlagValue
             });
-            for (const component of components) {
-              expect(client.mongoLogger.componentSeverities).to.have.property(
-                component,
-                SeverityLevel.OFF
-              );
-            }
+            expect(client.mongoLogger).to.not.exist;
           });
         });
       });
@@ -162,7 +141,7 @@ describe('Feature Flags', () => {
           [Symbol.for('@@mdb.internalLoggerConfig')]: undefined
         });
 
-        expect(client.mongoLogger.componentSeverities).to.have.property(
+        expect(client.mongoLogger?.componentSeverities).to.have.property(
           'command',
           SeverityLevel.EMERGENCY
         );
@@ -178,7 +157,7 @@ describe('Feature Flags', () => {
           }
         });
 
-        expect(client.mongoLogger.componentSeverities).to.have.property(
+        expect(client.mongoLogger?.componentSeverities).to.have.property(
           'command',
           SeverityLevel.ALERT
         );

test/unit/mongo_client.test.js

@@ -800,7 +800,10 @@ describe('MongoOptions', function () {
   context('loggingOptions', function () {
     const expectedLoggingObject = {
       maxDocumentLength: 20,
-      logDestination: new Writable()
+      logDestination: new Writable(),
+      componentSeverities: Object.fromEntries(
+        Object.values(MongoLoggableComponent).map(([value]) => [value, SeverityLevel.OFF])
+      )
     };
 
     before(() => {
@@ -1075,9 +1078,9 @@ describe('MongoOptions', function () {
               ).to.not.throw(MongoAPIError);
               const client = new MongoClient('mongodb://a/', {
                 [loggerFeatureFlag]: true,
-                mongodbLogComponentSeverities: {}
+                mongodbLogComponentSeverities: { client: 'error' } // dummy so logger doesn't turn on
               });
-              expect(client.mongoLogger.componentSeverities.default).to.equal('off');
+              expect(client.mongoLogger?.componentSeverities.command).to.equal('off');
             });
           });
           context('when valid client option is provided', function () {
@@ -1091,9 +1094,9 @@ describe('MongoOptions', function () {
               ).to.not.throw(MongoAPIError);
               const client = new MongoClient('mongodb://a/', {
                 [loggerFeatureFlag]: true,
-                mongodbLogComponentSeverities: { default: 'emergency' }
+                mongodbLogComponentSeverities: { command: 'emergency' }
               });
-              expect(client.mongoLogger.componentSeverities.default).to.equal('emergency');
+              expect(client.mongoLogger?.componentSeverities.command).to.equal('emergency');
             });
           });
         });