Perbarui item DynamoDB secara kondisional dengan TTL menggunakan SDK AWS

Contoh kode berikut menunjukkan cara memperbarui TTL item secara kondisional.

Java

SDK untuk Java 2.x

// 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);
    }
}

• Untuk detail API, lihat UpdateItemdi Referensi AWS SDK for Java 2.x API.

JavaScript

SDK untuk JavaScript (v3)

Perbarui TTL pada Item DynamoDB yang ada dalam tabel, dengan kondisi.

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');

• Untuk detail API, lihat UpdateItemdi Referensi AWS SDK for JavaScript API.

Python

SDK untuk Python (Boto3)

# 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')

• Untuk detail API, lihat UpdateItemdi AWS SDK for Python (Boto3) Referensi API.

Untuk daftar lengkap panduan pengembang AWS SDK dan contoh kode, lihatMenggunakan DynamoDB dengan SDK AWS. Topik ini juga mencakup informasi tentang memulai dan detail tentang versi SDK sebelumnya.