test cases passing

Author: aditi-khare-mongoDB

src/mongo_client.ts

@@ -364,6 +364,52 @@ 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.endsWith('.docdb.amazonaws.com') ||
+            hostAddress.host.endsWith('.docdb-elastic.amazonaws.com'))
+      );
+
+      const srvHostIsDocumentDB =
+        this[kOptions].srvHost &&
+        (this[kOptions].srvHost.endsWith('.docdb.amazonaws.com') ||
+          this[kOptions].srvHost.endsWith('.docdb-elastic.amazonaws.com'));
+
+      if (documentDBHostnames.length !== 0 || srvHostIsDocumentDB) {
+        this.mongoLogger.logDestination.write({
+          t: new Date(),
+          c: 'topology',
+          s: 'info',
+          message:
+            '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.endsWith('.cosmos.azure.com')
+      );
+
+      const srvHostIsCosmosDB =
+        this[kOptions].srvHost && this[kOptions].srvHost.endsWith('.cosmos.azure.com');
+
+      if (cosmosDBHostnames.length !== 0 || srvHostIsCosmosDB) {
+        this.mongoLogger.logDestination.write({
+          t: new Date(),
+          c: 'topology',
+          s: 'info',
+          message:
+            '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 */

test/unit/connection_string.test.ts

@@ -883,4 +883,48 @@ describe('Connection String', function () {
       });
     });
   });
+
+  describe('non-genuine hosts', () => {
+    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/', ''],
+      ['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('message', message);
+          } else {
+            expect(stream.buffer).to.have.lengthOf(0);
+          }
+        });
+      }
+    });
+  });
 });