A transaction initiator service initiates or starts a transaction. Based on your application's business logic, a transaction initiator service may only start the transaction or start the transaction and participate in the transaction as well.

1. Add the MicroTx library for Node.js as a dependency in the package.json file.

   "dependencies": {
       "@oracle/microtx": "<version>"
     }

   Where, <version> is the latest version of the MicroTx library for Node.js.

2. Configure the property values for the MicroTx library. See Configure Library Properties for JAX-RS and Node.js Apps. To enable logging for Node.js applications, you must set additional properties. See Enable Logs for MicroTx Node.js Library.
3. Configure the MicroTx library properties for the microservice by passing the tmm.properties file in which you have defined the values.

   TrmConfig.init('./tmm.properties');

4. Edit the application code to:
   1. Create a TrmUserTransaction object.
   2. To begin a transaction, call begin() on the TrmUserTransaction object that you have created. The parameters that you pass when you call begin() depend on whether your application only initiates the transaction or also participates in it.
   3. To commit or rollback the transaction, call commit() or rollback() on the TrmUserTransaction object that you have created.

   The following example shows how to create a TrmUserTransaction object named ut, and then begin, commit or rollback a transaction. Here req represents the request.

   //Step 3(a): Create a TrmUserTransaction object
   let ut: TrmUserTransaction = newTrmUserTransaction();
   
   //Optional. Specify the amount of time, in milliseconds, for which the transaction remains active. 
   //If a transaction is not committed or rolled back within the specified time period, the transaction is rolled back.
   ut.setTransactionTimeout(60000);
   
   try {
     //Step 3(b): Transaction demarcation - (start)
     await ut.begin(req);  //If your application only initiates the transaction and does not participate in it.
     await ut.begin(req, true);  //If your application initiates the transaction and participates in it.
   
     ... // implement business logic
     
     await ut.commit(req); //Step 3(c): Transaction demarcation - commit (end)
   
     resp.status(200).send("Transaction complete.");
   } 
   catch (e) {
     console.log("Transaction Failed: ", e);
     let message = e.message;
     try {
       console.log("Rollback on transaction failure.");
       await ut.rollback(req); //Step 3.c: Transaction rollback (end)
       message = message + ". Transaction rolled back. ";
     } catch (ex) {
       console.log("Error in rollback for transfer failure: ", ex);
     }
     resp.status(500).send(message);
   }

   The example code is implemented in a try-catch statement, so that errors, if any, are handled gracefully. You can also implement your sample code without using a try-catch statement.

5. Save the changes, and then deploy your application. See Deploy Your Application.