feat(NODE-5452): Logging Cosmos Document DB Info Message (#3902)

Co-authored-by: Durran Jordan <durran@gmail.com>

src/connection_string.ts

@@ -523,6 +523,7 @@ export function parseOptions(
       MONGODB_LOG_TOPOLOGY: process.env.MONGODB_LOG_TOPOLOGY,
       MONGODB_LOG_SERVER_SELECTION: process.env.MONGODB_LOG_SERVER_SELECTION,
       MONGODB_LOG_CONNECTION: process.env.MONGODB_LOG_CONNECTION,
+      MONGODB_LOG_CLIENT: process.env.MONGODB_LOG_CLIENT,
       MONGODB_LOG_ALL: process.env.MONGODB_LOG_ALL,
       MONGODB_LOG_MAX_DOCUMENT_LENGTH: process.env.MONGODB_LOG_MAX_DOCUMENT_LENGTH,
       MONGODB_LOG_PATH: process.env.MONGODB_LOG_PATH,

src/mongo_client.ts

@@ -33,8 +33,13 @@ import type { SrvPoller } from './sdam/srv_polling';
 import { Topology, type TopologyEvents } from './sdam/topology';
 import { ClientSession, type ClientSessionOptions, ServerSessionPool } from './sessions';
 import {
+  COSMOS_DB_CHECK,
+  COSMOS_DB_MSG,
+  DOCUMENT_DB_CHECK,
+  DOCUMENT_DB_MSG,
   type HostAddress,
   hostMatchesWildcards,
+  isHostMatch,
   type MongoDBNamespace,
   ns,
   resolveOptions
@@ -364,6 +369,26 @@ export class MongoClient extends TypedEventEmitter<MongoClientEvents> {
         return true;
       }
     };
+    this.checkForNonGenuineHosts();
+  }
+
+  /** @internal */
+  private checkForNonGenuineHosts() {
+    const documentDBHostnames = this[kOptions].hosts.filter((hostAddress: HostAddress) =>
+      isHostMatch(DOCUMENT_DB_CHECK, hostAddress.host)
+    );
+    const srvHostIsDocumentDB = isHostMatch(DOCUMENT_DB_CHECK, this[kOptions].srvHost);
+
+    const cosmosDBHostnames = this[kOptions].hosts.filter((hostAddress: HostAddress) =>
+      isHostMatch(COSMOS_DB_CHECK, hostAddress.host)
+    );
+    const srvHostIsCosmosDB = isHostMatch(COSMOS_DB_CHECK, this[kOptions].srvHost);
+
+    if (documentDBHostnames.length !== 0 || srvHostIsDocumentDB) {
+      this.mongoLogger.info('client', DOCUMENT_DB_MSG);
+    } else if (cosmosDBHostnames.length !== 0 || srvHostIsCosmosDB) {
+      this.mongoLogger.info('client', COSMOS_DB_MSG);
+    }
   }
 
   /** @see MongoOptions */

src/mongo_logger.ts

@@ -98,7 +98,8 @@ export const MongoLoggableComponent = Object.freeze({
   COMMAND: 'command',
   TOPOLOGY: 'topology',
   SERVER_SELECTION: 'serverSelection',
-  CONNECTION: 'connection'
+  CONNECTION: 'connection',
+  CLIENT: 'client'
 } as const);
 
 /** @internal */
@@ -115,6 +116,8 @@ export interface MongoLoggerEnvOptions {
   MONGODB_LOG_SERVER_SELECTION?: string;
   /** Severity level for CMAP */
   MONGODB_LOG_CONNECTION?: string;
+  /** Severity level for client */
+  MONGODB_LOG_CLIENT?: string;
   /** Default severity level to be if any of the above are unset */
   MONGODB_LOG_ALL?: string;
   /** Max length of embedded EJSON docs. Setting to 0 disables truncation. Defaults to 1000. */
@@ -140,6 +143,8 @@ export interface MongoLoggerOptions {
     serverSelection: SeverityLevel;
     /** Severity level for connection component */
     connection: SeverityLevel;
+    /** Severity level for client component */
+    client: SeverityLevel;
     /** Default severity level to be used if any of the above are unset */
     default: SeverityLevel;
   };
@@ -528,6 +533,7 @@ export class MongoLogger {
           parseSeverityFromString(combinedOptions.MONGODB_LOG_SERVER_SELECTION) ?? defaultSeverity,
         connection:
           parseSeverityFromString(combinedOptions.MONGODB_LOG_CONNECTION) ?? defaultSeverity,
+        client: parseSeverityFromString(combinedOptions.MONGODB_LOG_CLIENT) ?? defaultSeverity,
         default: defaultSeverity
       },
       maxDocumentLength:

src/utils.ts

@@ -1282,3 +1282,20 @@ export class TimeoutController extends AbortController {
     this.timeoutId = null;
   }
 }
+
+/** @internal */
+export const DOCUMENT_DB_CHECK = /(\.docdb\.amazonaws\.com$)|(\.docdb-elastic\.amazonaws\.com$)/;
+/** @internal */
+export const COSMOS_DB_CHECK = /\.cosmos\.azure\.com$/;
+
+/** @internal */
+export const DOCUMENT_DB_MSG =
+  'You appear to be connected to a DocumentDB cluster. For more information regarding feature compatibility and support please visit https://www.mongodb.com/supportability/documentdb';
+/** @internal */
+export const COSMOS_DB_MSG =
+  'You appear to be connected to a CosmosDB cluster. For more information regarding feature compatibility and support please visit https://www.mongodb.com/supportability/cosmosdb';
+
+/** @internal */
+export function isHostMatch(match: RegExp, host?: string): boolean {
+  return host && match.test(host.toLowerCase()) ? true : false;
+}

test/unit/connection_string.test.ts

@@ -9,7 +9,9 @@ import { inspect } from 'util';
 import {
   AUTH_MECHS_AUTH_SRC_EXTERNAL,
   AuthMechanism,
+  COSMOS_DB_MSG,
   DEFAULT_ALLOWED_HOSTS,
+  DOCUMENT_DB_MSG,
   FEATURE_FLAGS,
   type Log,
   MongoAPIError,
@@ -883,4 +885,58 @@ describe('Connection String', function () {
       });
     });
   });
+
+  describe('non-genuine hosts', () => {
+    beforeEach(() => {
+      process.env.MONGODB_LOG_CLIENT = 'info';
+    });
+
+    afterEach(() => {
+      process.env.MONGODB_LOG_CLIENT = undefined;
+    });
+
+    const loggerFeatureFlag = Symbol.for('@@mdb.enableMongoLogger');
+    const test_cases = [
+      ['non-SRV example uri', 'mongodb://a.example.com:27017,b.example.com:27017/', ''],
+      ['non-SRV default uri', 'mongodb://a.mongodb.net:27017', ''],
+      ['SRV example uri', 'mongodb+srv://a.example.com/', ''],
+      ['SRV default uri', 'mongodb+srv://a.mongodb.net/', ''],
+      // ensure case insensitity
+      ['non-SRV cosmosDB uri', 'mongodb://a.mongo.COSmos.aZure.com:19555/', COSMOS_DB_MSG],
+      ['non-SRV documentDB uri', 'mongodb://a.docDB.AmazonAws.com:27017/', DOCUMENT_DB_MSG],
+      [
+        'non-SRV documentDB uri ',
+        'mongodb://a.docdB-eLasTic.amazonaws.com:27017/',
+        DOCUMENT_DB_MSG
+      ],
+      ['SRV cosmosDB uri', 'mongodb+srv://a.mongo.COSmos.aZure.com/', COSMOS_DB_MSG],
+      ['SRV documentDB uri', 'mongodb+srv://a.docDB.AmazonAws.com/', DOCUMENT_DB_MSG],
+      ['SRV documentDB uri 2', 'mongodb+srv://a.docdB-eLastic.amazonaws.com/', DOCUMENT_DB_MSG]
+    ];
+
+    context('when logging is turned on', () => {
+      for (const [name, uri, message] of test_cases) {
+        it(`${name} triggers ${message.length === 0 ? 'no' : 'correct info'} msg`, () => {
+          const stream = {
+            buffer: [],
+            write(log) {
+              this.buffer.push(log);
+            }
+          };
+          new MongoClient(uri, {
+            [loggerFeatureFlag]: true,
+            mongodbLogPath: stream
+          });
+
+          if (message.length > 0) {
+            expect(stream.buffer).to.have.lengthOf(1);
+            expect(stream.buffer[0]).to.have.property('c', 'client');
+            expect(stream.buffer[0]).to.have.property('message', message);
+          } else {
+            expect(stream.buffer).to.have.lengthOf(0);
+          }
+        });
+      }
+    });
+  });
 });

test/unit/mongo_logger.test.ts

@@ -116,7 +116,8 @@ describe('class MongoLogger', function () {
         ['MONGODB_LOG_COMMAND', 'command'],
         ['MONGODB_LOG_TOPOLOGY', 'topology'],
         ['MONGODB_LOG_SERVER_SELECTION', 'serverSelection'],
-        ['MONGODB_LOG_CONNECTION', 'connection']
+        ['MONGODB_LOG_CONNECTION', 'connection'],
+        ['MONGODB_LOG_CLIENT', 'client']
       ]);
 
       function* makeValidOptions(): Generator<[string, string]> {