Actualización condicional de un elemento de DynamoDB con un TTL mediante un AWS SDK
En los siguientes ejemplos de código se muestra cómo actualizar de forma condicional el TTL de un elemento.
- Java
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- SDK para Java 2.x
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// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. // SPDX-License-Identifier: Apache-2.0 package com.amazon.samplelib.ttl; import software.amazon.awssdk.regions.Region; import software.amazon.awssdk.services.dynamodb.DynamoDbClient; import software.amazon.awssdk.services.dynamodb.model.AttributeValue; import software.amazon.awssdk.services.dynamodb.model.DynamoDbException; import software.amazon.awssdk.services.dynamodb.model.ResourceNotFoundException; import software.amazon.awssdk.services.dynamodb.model.UpdateItemRequest; import software.amazon.awssdk.services.dynamodb.model.UpdateItemResponse; import software.amazon.awssdk.utils.ImmutableMap; import java.util.Map; import java.util.Optional; public class UpdateTTLConditional { public static void main(String[] args) { final String usage = """ Usage: <tableName> <primaryKey> <sortKey> <newTtlAttribute> <region> Where: tableName - The Amazon DynamoDB table being queried. primaryKey - The name of the primary key. Also known as the hash or partition key. sortKey - The name of the sort key. Also known as the range attribute. newTtlAttribute - New attribute name (as part of the update command) region (optional) - The AWS region that the Amazon DynamoDB table is located in. (Default: us-east-1) """; // Optional "region" parameter - if args list length is NOT 3 or 4, short-circuit exit. if (!(args.length == 4 || args.length == 5)) { System.out.println(usage); System.exit(1); } final String tableName = args[0]; final String primaryKey = args[1]; final String sortKey = args[2]; final String newTtlAttribute = args[3]; Region region = Optional.ofNullable(args[4]).isEmpty() ? Region.US_EAST_1 : Region.of(args[4]); // Get current time in epoch second format final long currentTime = System.currentTimeMillis() / 1000; // Calculate expiration time 90 days from now in epoch second format final long expireDate = currentTime + (90 * 24 * 60 * 60); // An expression that defines one or more attributes to be updated, the action to be performed on them, and new values for them. final String updateExpression = "SET newTtlAttribute = :val1"; // A condition that must be satisfied in order for a conditional update to succeed. final String conditionExpression = "expireAt > :val2"; final ImmutableMap<String, AttributeValue> keyMap = ImmutableMap.of("primaryKey", AttributeValue.fromS(primaryKey), "sortKey", AttributeValue.fromS(sortKey)); final Map<String, AttributeValue> expressionAttributeValues = ImmutableMap.of( ":val1", AttributeValue.builder().s(newTtlAttribute).build(), ":val2", AttributeValue.builder().s(String.valueOf(expireDate)).build() ); final UpdateItemRequest request = UpdateItemRequest.builder() .tableName(tableName) .key(keyMap) .updateExpression(updateExpression) .conditionExpression(conditionExpression) .expressionAttributeValues(expressionAttributeValues) .build(); try (DynamoDbClient ddb = DynamoDbClient.builder() .region(region) .build()) { final UpdateItemResponse response = ddb.updateItem(request); System.out.println(tableName + " UpdateItem operation with conditional TTL successful. Request id is " + response.responseMetadata().requestId()); } catch (ResourceNotFoundException e) { System.err.format("Error: The Amazon DynamoDB table \"%s\" can't be found.\n", tableName); System.exit(1); } catch (DynamoDbException e) { System.err.println(e.getMessage()); System.exit(1); } System.exit(0); } }
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Para obtener información sobre la API, consulte UpdateItem en la referencia de la API de AWS SDK for Java 2.x.
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- JavaScript
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- SDK para JavaScript (v3)
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Actualice el TTL en un elemento de DynamoDB existente en una tabla con una condición.
import { DynamoDBClient, UpdateItemCommand } from "@aws-sdk/client-dynamodb"; import { marshall, unmarshall } from "@aws-sdk/util-dynamodb"; const updateDynamoDBItem = async (tableName, region, partitionKey, sortKey, newAttribute) => { const client = new DynamoDBClient({ region: region, endpoint: `https://dynamodb.${region}.amazonaws.com` }); const currentTime = Math.floor(Date.now() / 1000); const params = { TableName: tableName, Key: marshall({ artist: partitionKey, album: sortKey }), UpdateExpression: "SET newAttribute = :newAttribute", ConditionExpression: "expireAt > :expiration", ExpressionAttributeValues: marshall({ ':newAttribute': newAttribute, ':expiration': currentTime }), ReturnValues: "ALL_NEW" }; try { const response = await client.send(new UpdateItemCommand(params)); const responseData = unmarshall(response.Attributes); console.log("Item updated successfully: ", responseData); return responseData; } catch (error) { if (error.name === "ConditionalCheckFailedException") { console.log("Condition check failed: Item's 'expireAt' is expired."); } else { console.error("Error updating item: ", error); } throw error; } }; // Enter your values here updateDynamoDBItem('your-table-name', "us-east-1",'your-partition-key-value', 'your-sort-key-value', 'your-new-attribute-value');
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Para obtener información sobre la API, consulte UpdateItem en la referencia de la API de AWS SDK for JavaScript.
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- Python
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- SDK para Python (Boto3)
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# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. # SPDX-License-Identifier: Apache-2.0 import boto3 from datetime import datetime, timedelta from botocore.exceptions import ClientError def update_dynamodb_item(table_name, region, primary_key, sort_key, ttl_attribute): """ Updates an existing record in a DynamoDB table with a new or updated TTL attribute. :param table_name: Name of the DynamoDB table :param region: AWS Region of the table - example `us-east-1` :param primary_key: one attribute known as the partition key. :param sort_key: Also known as a range attribute. :param ttl_attribute: name of the TTL attribute in the target DynamoDB table :return: """ try: dynamodb = boto3.resource('dynamodb', region_name=region) table = dynamodb.Table(table_name) # Generate updated TTL in epoch second format updated_expiration_time = int((datetime.now() + timedelta(days=90)).timestamp()) # Define the update expression for adding/updating a new attribute update_expression = "SET newAttribute = :val1" # Define the condition expression for checking if 'expireAt' is not expired condition_expression = "expireAt > :val2" # Define the expression attribute values expression_attribute_values = { ':val1': ttl_attribute, ':val2': updated_expiration_time } response = table.update_item( Key={ 'primaryKey': primary_key, 'sortKey': sort_key }, UpdateExpression=update_expression, ConditionExpression=condition_expression, ExpressionAttributeValues=expression_attribute_values ) print("Item updated successfully.") return response['ResponseMetadata']['HTTPStatusCode'] # Ideally a 200 OK except ClientError as e: if e.response['Error']['Code'] == "ConditionalCheckFailedException": print("Condition check failed: Item's 'expireAt' is expired.") else: print(f"Error updating item: {e}") except Exception as e: print(f"Error updating item: {e}") # replace with your values update_dynamodb_item('your-table-name', 'us-east-1', 'your-partition-key-value', 'your-sort-key-value', 'your-ttl-attribute-value')
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Para obtener información la API, consulte UpdateItem en la referencia de la API de AWS SDK para Python (Boto3).
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Para obtener una lista completa de las guías para desarrolladores del AWS SDK y ejemplos de código, consulte Uso de DynamoDB con un SDK de AWS. En este tema también se incluye información sobre cómo comenzar a utilizar el SDK y detalles sobre sus versiones anteriores.