Passaggio 9 (opzionale): Pulisci le risorse

Per eliminare il libro mastro

1. Compila ed esegui il seguente programma (DeleteLedger.java) per eliminare il vehicle-registration registro e tutto il suo contenuto.

   /*
    * 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.
    */
   
   package software.amazon.qldb.tutorial;
   
   import com.amazonaws.services.qldb.AmazonQLDB;
   import com.amazonaws.services.qldb.model.DeleteLedgerRequest;
   import com.amazonaws.services.qldb.model.DeleteLedgerResult;
   import com.amazonaws.services.qldb.model.ResourceNotFoundException;
   import com.amazonaws.services.qldb.model.UpdateLedgerRequest;
   import com.amazonaws.services.qldb.model.UpdateLedgerResult;
   
   import org.slf4j.Logger;
   import org.slf4j.LoggerFactory;
   
   /**
    * Delete a ledger.
    *
    * This code expects that you have AWS credentials setup per:
    * http://docs.aws.amazon.com/java-sdk/latest/developer-guide/setup-credentials.html
    */
   public final class DeleteLedger {
       public static final Logger log = LoggerFactory.getLogger(DeleteLedger.class);
       public static final Long LEDGER_DELETION_POLL_PERIOD_MS = 20_000L;
       public static AmazonQLDB client = CreateLedger.getClient();
   
       private DeleteLedger() { }
   
       public static void main(String... args) throws Exception {
           try {
               setDeletionProtection(Constants.LEDGER_NAME, false);
   
               delete(Constants.LEDGER_NAME);
   
               waitForDeleted(Constants.LEDGER_NAME);
   
           } catch (Exception e) {
               log.error("Unable to delete the ledger.", e);
               throw e;
           }
       }
   
       /**
        * Send a request to the QLDB database to delete the specified ledger.
        *
        * @param ledgerName
        *              Name of the ledger to be deleted.
        * @return DeleteLedgerResult.
        */
       public static DeleteLedgerResult delete(final String ledgerName) {
           log.info("Attempting to delete the ledger with name: {}...", ledgerName);
           DeleteLedgerRequest request = new DeleteLedgerRequest().withName(ledgerName);
           DeleteLedgerResult result = client.deleteLedger(request);
           log.info("Success.");
           return result;
       }
   
       /**
        * Wait for the ledger to be deleted.
        *
        * @param ledgerName
        *              Name of the ledger being deleted.
        * @throws InterruptedException if thread is being interrupted.
        */
       public static void waitForDeleted(final String ledgerName) throws InterruptedException {
           log.info("Waiting for the ledger to be deleted...");
           while (true) {
               try {
                   DescribeLedger.describe(ledgerName);
                   log.info("The ledger is still being deleted. Please wait...");
                   Thread.sleep(LEDGER_DELETION_POLL_PERIOD_MS);
               } catch (ResourceNotFoundException ex) {
                   log.info("Success. The ledger is deleted.");
                   break;
               }
           }
       }
       
       public static UpdateLedgerResult setDeletionProtection(String ledgerName, boolean deletionProtection) {
           log.info("Let's set deletionProtection to {} for the ledger with name {}", deletionProtection, ledgerName);
           UpdateLedgerRequest request = new UpdateLedgerRequest()
                   .withName(ledgerName)
                   .withDeletionProtection(deletionProtection);
   
           UpdateLedgerResult result = client.updateLedger(request);
           log.info("Success. Ledger updated: {}", result);
           return result;
       }
   }
   

   Nota

   Se la protezione da eliminazione è abilitata per il registro, è necessario prima disabilitarla prima di poter eliminare il registro utilizzando il. QLDB API

2. Se hai esportato i dati del journal nel passaggio precedente e non ne hai più bisogno, usa la console Amazon S3 per eliminare il tuo bucket S3.

   Apri la console Amazon S3 all'indirizzo. https://console.aws.amazon.com/s3/