Step 8 (optional): Clean up resources

You can continue using the vehicle-registration ledger. However, if you no longer need it, you should delete it.

To delete the ledger

1. Use the following program (DeleteLedger.ts) to delete your vehicle-registration ledger and all of its contents.

   /*
    * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
    * SPDX-License-Identifier: MIT-0
    *
    * Permission is hereby granted, free of charge, to any person obtaining a copy of this
    * software and associated documentation files (the "Software"), to deal in the Software
    * without restriction, including without limitation the rights to use, copy, modify,
    * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
    * permit persons to whom the Software is furnished to do so.
    *
    * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
    * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
    * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
    * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
    * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
    * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    */
   
   import { isResourceNotFoundException } from "amazon-qldb-driver-nodejs";
   import { AWSError, QLDB } from "aws-sdk";
   import { DeleteLedgerRequest, DescribeLedgerRequest } from "aws-sdk/clients/qldb";
   
   import { setDeletionProtection } from "./DeletionProtection";
   import { LEDGER_NAME } from "./qldb/Constants";
   import { error, log } from "./qldb/LogUtil";
   import { sleep } from "./qldb/Util";
   
   const LEDGER_DELETION_POLL_PERIOD_MS = 20000;
   
   /**
    * Send a request to QLDB to delete the specified ledger.
    * @param ledgerName Name of the ledger to be deleted.
    * @param qldbClient The QLDB control plane client to use.
    * @returns Promise which fulfills with void.
    */
   export async function deleteLedger(ledgerName: string, qldbClient: QLDB): Promise<void> {
       log(`Attempting to delete the ledger with name: ${ledgerName}`);
       const request: DeleteLedgerRequest = {
           Name: ledgerName
       };
       await qldbClient.deleteLedger(request).promise();
       log("Success.");
   }
   
   /**
    * Wait for the ledger to be deleted.
    * @param ledgerName Name of the ledger to be deleted.
    * @param qldbClient The QLDB control plane client to use.
    * @returns Promise which fulfills with void.
    */
   export async function waitForDeleted(ledgerName: string, qldbClient: QLDB): Promise<void> {
       log("Waiting for the ledger to be deleted...");
       const request: DescribeLedgerRequest = {
           Name: ledgerName
       };
       let isDeleted: boolean = false;
       while (true) {
           await qldbClient.describeLedger(request).promise().catch((error: AWSError) => {
               if (isResourceNotFoundException(error)) {
                   isDeleted = true;
                   log("Success. Ledger is deleted.");
               }
           });
           if (isDeleted) {
               break;
           }
           log("The ledger is still being deleted. Please wait...");
           await sleep(LEDGER_DELETION_POLL_PERIOD_MS);
       }
   }
   
   /**
    * Delete a ledger.
    * @returns Promise which fulfills with void.
    */
   const main = async function(): Promise<void> {
       try {
           const qldbClient: QLDB = new QLDB();
           await setDeletionProtection(LEDGER_NAME, qldbClient, false);
           await deleteLedger(LEDGER_NAME, qldbClient);
           await waitForDeleted(LEDGER_NAME, qldbClient);
       } catch (e) {
           error(`Unable to delete the ledger: ${e}`);
       }
   }
   
   if (require.main === module) {
       main();
   }

   Note

   If deletion protection is enabled for your ledger, you must first disable it before you can delete the ledger using the QLDB API.

2. To run the transpiled program, enter the following command.

   node dist/DeleteLedger.js