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

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

@@ -364,6 +364,47 @@ export class MongoClient extends TypedEventEmitter<MongoClientEvents> {
         return true;
       }
     };
+    this.checkForNonGenuineHosts();
+  }
+
+  /** @internal */
+  private checkForNonGenuineHosts() {
+    if (this.mongoLogger && this.mongoLogger.logDestination) {
+      const documentDBHostnames = this[kOptions].hosts.filter(
+        (hostAddress: HostAddress) =>
+          hostAddress.host &&
+          (hostAddress.host.toLowerCase().endsWith('.docdb.amazonaws.com') ||
+            hostAddress.host.toLowerCase().endsWith('.docdb-elastic.amazonaws.com'))
+      );
+
+      const srvHostIsDocumentDB =
+        this[kOptions].srvHost &&
+        (this[kOptions].srvHost.toLowerCase().endsWith('.docdb.amazonaws.com') ||
+          this[kOptions].srvHost.toLowerCase().endsWith('.docdb-elastic.amazonaws.com'));
+
+      if (documentDBHostnames.length !== 0 || srvHostIsDocumentDB) {
+        this.mongoLogger.info(
+          'client',
+          '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'
+        );
+      }
+
+      const cosmosDBHostnames = this[kOptions].hosts.filter(
+        (hostAddress: HostAddress) =>
+          hostAddress.host && hostAddress.host.toLowerCase().endsWith('.cosmos.azure.com')
+      );
+
+      const srvHostIsCosmosDB =
+        this[kOptions].srvHost &&
+        this[kOptions].srvHost.toLowerCase().endsWith('.cosmos.azure.com');
+
+      if (cosmosDBHostnames.length !== 0 || srvHostIsCosmosDB) {
+        this.mongoLogger.info(
+          'client',
+          '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'
+        );
+      }
+    }
   }
 
   /** @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:

test/unit/connection_string.test.ts

@@ -883,4 +883,58 @@ 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 docDBmsg =
+      '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';
+    const cosmosDBmsg =
+      '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';
+    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/', cosmosDBmsg],
+      ['non-SRV documentDB uri', 'mongodb://a.docDB.AmazonAws.com:27017/', docDBmsg],
+      ['non-SRV documentDB uri ', 'mongodb://a.docdB-eLasTic.amazonaws.com:27017/', docDBmsg],
+      ['SRV cosmosDB uri', 'mongodb+srv://a.mongo.COSmos.aZure.com/', cosmosDBmsg],
+      ['SRV documentDB uri', 'mongodb+srv://a.docDB.AmazonAws.com/', docDBmsg],
+      ['SRV documentDB uri 2', 'mongodb+srv://a.docdB-eLastic.amazonaws.com/', docDBmsg]
+    ];
+
+    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]> {