Use SDK metrics from the AWS SDK for Java

With the AWS SDK for Java 2.x, you can collect metrics about the service clients in your application, analyze the output in Amazon CloudWatch, and then act on it.

By default, metrics collection is disabled in the SDK. This topic helps you to enable and configure it.

Prerequisites

Before you can enable and use metrics, you must complete the following steps:

How to enable metrics collection

You can enable metrics in your application for a service client or on individual requests.

Enable metrics for a specific request

The following class shows how to enable the CloudWatch metrics publisher for a request to Amazon DynamoDB. It uses the default metrics publisher configuration.

import software.amazon.awssdk.metrics.MetricPublisher;
import software.amazon.awssdk.metrics.publishers.cloudwatch.CloudWatchMetricPublisher;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.ListTablesRequest;

public class DefaultConfigForRequest {
    // Use one MetricPublisher for your application. It can be used with requests or service clients.
    static MetricPublisher metricsPub = CloudWatchMetricPublisher.create();

    public static void main(String[] args) {
        DynamoDbClient ddb = DynamoDbClient.create();
        // Publish metrics the for ListTables operation.
        ddb.listTables(ListTablesRequest.builder()
            .overrideConfiguration(c -> c.addMetricPublisher(metricsPub))
            .build());

        // Perform more work in your application.

        // A MetricsPublisher has its own lifecycle independent of any service client or request that uses it.
        // If you no longer need the publisher, close it to free up resources.
        metricsPub.close();  // All metrics stored in memory are flushed to CloudWatch.

        // Perform more work with the DynamoDbClient instance without publishing metrics.
        // Close the service client when you no longer need it.
        ddb.close();
    }
}

Enable summary metrics for a specific service client

The following code snippet shows how to enable a CloudWatch metrics publisher with default settings for a service client.

MetricPublisher metricsPub = CloudWatchMetricPublisher.create();

DynamoDbClient ddb = DynamoDbClient.builder()
          .overrideConfiguration(c -> c.addMetricPublisher(metricsPub))
          .build();

Customize metrics publisher

The following class demonstrates how to set up a custom configuration for the metrics publisher for a specific service client. The customizations include loading a specific profile, specifying a AWS Region where the metrics publisher sends requests, and customizing how often the publisher sends metrics to CloudWatch.

import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.core.metrics.CoreMetric;
import software.amazon.awssdk.metrics.MetricPublisher;
import software.amazon.awssdk.metrics.publishers.cloudwatch.CloudWatchMetricPublisher;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.cloudwatch.CloudWatchAsyncClient;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;

import java.time.Duration;

public class CustomConfigForDDBClient {
    // Use one MetricPublisher for your application. It can be used with requests or service clients.
    static MetricPublisher metricsPub = CloudWatchMetricPublisher.builder()
        .cloudWatchClient(CloudWatchAsyncClient.builder()
            .region(Region.US_WEST_2)
            .credentialsProvider(ProfileCredentialsProvider.create("cloudwatch"))
            .build())
        .uploadFrequency(Duration.ofMinutes(5))
        .maximumCallsPerUpload(100)
        .namespace("ExampleSDKV2Metrics")
        .detailedMetrics(CoreMetric.API_CALL_DURATION)
        .build();

    public static void main(String[] args) {
        DynamoDbClient ddb = DynamoDbClient.builder()
            .overrideConfiguration(c -> c.addMetricPublisher(metricsPub))
            .build();
        // Publish metrics for DynamoDB operations.
        ddb.listTables();
        ddb.describeEndpoints();
        ddb.describeLimits();
        // Perform more work in your application.

        // A MetricsPublisher has its own lifecycle independent of any service client or request that uses it.
        // If you no longer need the publisher, close it to free up resources.
        metricsPub.close();  // All metrics stored in memory are flushed to CloudWatch.


        // Perform more work with the DynamoDbClient instance without publishing metrics.
        // Close the service client when you no longer need it.
        ddb.close();
    }
}

The customizations shown in the previous snippet have the following effects.

When are metrics available?

Metrics are generally available within 5-10 minutes after the SDK for Java emits them. For accurate and up-to-date metrics, check Cloudwatch at least 10 minutes after emitting the metrics from your Java applications.

What information is collected?

Metrics collection includes the following:

For a complete list, see Service client metrics.

How can I use this information?

You can use the metrics the SDK collects to monitor the service clients in your application. You can look at overall usage trends, identify anomalies, review service client exceptions returned, or to dig in to understand a particular issue. Using Amazon CloudWatch, you can also create alarms to notify you as soon as your application reaches a condition that you define.

For more information, see Using Amazon CloudWatch Metrics and Using Amazon CloudWatch Alarms in the Amazon CloudWatch User Guide.