Post

Understanding ThrottlingException in Amazon Bedrock: Best Practices and Code Examples

Amazon Bedrock is a powerful platform that provides machine learning services for developers. However, like any other cloud service, it is subject to certain limitations, which can lead to errors such as ThrottlingException. In this article, we will dive deep into what the ThrottlingException is, why it occurs, how to catch and handle it, and offer some best practices to avoid it. By the end of this tutorial, you’ll be equipped with the knowledge to make your applications more resilient when working with Amazon Bedrock.

What is ThrottlingException?

ThrottlingException is a specific error thrown by the Amazon Bedrock SDK when a request rate exceeds the service’s predefined limits. Amazon Web Services (AWS) imposes these limits to ensure fair usage and maintain the service’s overall performance. When your application makes too many requests in a short time, you may encounter this exception.

Common Causes of ThrottlingException

  • High Request Frequency: Sending multiple requests in rapid succession.
  • Burst Traffic: An unexpected spike in user requests.
  • Resource Limits: Hitting the defined service limits for your AWS account.

When to Expect ThrottlingException?

You are most likely to experience ThrottlingException during:

  • Batch processing with high concurrency.
  • API integrations that make frequent calls to the Bedrock service.
  • Stress testing without proper throttling control.

How to Handle ThrottlingException

Handling ThrottlingException gracefully in your application is crucial for creating a robust user experience. Below are some best practices and code examples.

1. Implement Exponential Backoff

When you encounter a ThrottlingException, the first step is to implement an exponential backoff strategy. This means that after receiving a throttling error, you wait for a specified amount of time before retrying the request. The wait time increases exponentially with each subsequent retry until it reaches a maximum threshold.

Example Code in Java:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
import com.amazonaws.services.bedrock.model.ThrottlingException;

public void callBedrockService() {
    int maxRetries = 5;
    int retryCount = 0;
    long waitTime = 1000; // initial wait time in milliseconds

    while (retryCount < maxRetries) {
        try {
            // Your API call to Bedrock goes here
            sendRequestToBedrock();
            break; // exit loop if the request is successful
        } catch (ThrottlingException e) {
            retryCount++;
            if (retryCount < maxRetries) {
                try {
                    Thread.sleep(waitTime);
                } catch (InterruptedException ie) {
                    Thread.currentThread().interrupt(); // restore interrupted status
                }
                waitTime *= 2; // double the wait time
            } else {
                System.out.println("Max retries reached. Handle the error accordingly.");
            }
        }
    }
}

2. Use Rate Limiting

In addition to exponential backoff, implementing rate limiting can also help mitigate the risk of encountering ThrottlingException. You can control how many requests your application sends to Bedrock in a given timeframe.

Example Code using a Token Bucket Algorithm:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

public class RateLimiter {
    private final int maxRequests;
    private final long interval;
    private int currentRequests = 0;
    
    public RateLimiter(int maxRequests, long interval) {
        this.maxRequests = maxRequests;
        this.interval = interval;
        
        // Start a goroutine to refill tokens
        Executors.newScheduledThreadPool(1).scheduleAtFixedRate(this::refillTokens, interval, interval, TimeUnit.MILLISECONDS);
    }
    
    private synchronized void refillTokens() {
        currentRequests = Math.min(currentRequests + 1, maxRequests);
    }

    public synchronized boolean allowRequest() {
        if (currentRequests > 0) {
            currentRequests--;
            return true;
        }
        return false;
    }

    public void callService() {
        if (allowRequest()) {
            // Call Bedrock Service
        } else {
            System.out.println("Request denied due to rate limiting.");
        }
    }
}

3. Monitor and Analyze Requests

Amazon CloudWatch can be used to set alarms and monitor API usage. By logging request metrics, you can track when you’re nearing throttling limits and adjust your request rates accordingly.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
import com.amazonaws.services.cloudwatch.AmazonCloudWatch;
import com.amazonaws.services.cloudwatch.AmazonCloudWatchClientBuilder;
import com.amazonaws.services.cloudwatch.model.*;

public class CloudWatchMonitor {
    private static final AmazonCloudWatch cloudWatch = AmazonCloudWatchClientBuilder.standard().build();

    public void logRequest() {
        PutMetricDataRequest request = new PutMetricDataRequest()
                .withNamespace("YourApplicationNamespace")
                .withMetricData(new MetricDatum()
                        .withMetricName("RequestCount")
                        .withValue(1.0)
                        .withUnit(StandardUnit.Count));
        cloudWatch.putMetricData(request);
    }
}

Best Practices for Avoiding ThrottlingException

  1. Batch Your Requests: Instead of making multiple individual requests, batch them together to reduce the total count of requests.

  2. Monitor Throughput: Regularly analyze your app’s request patterns and adjust your rate accordingly.

  3. Use Caching: Caching responses for frequently requested data can minimize API calls.

  4. Feedback Loops: Implement user feedback mechanisms so that they experience smooth UI interactions without overwhelming the backend services.

  5. Dynamic Adjustment: Adjust your application’s request rate dynamically based on the workload.

Conclusion

Understanding and handling ThrottlingException in Amazon Bedrock is crucial for building resilient applications. By implementing exponential backoff strategies, rate limiting, and monitoring usage, you can effectively mitigate the risks associated with request throttling.

You can find additional information in the official AWS documentation:

Feel free to reach out for further clarifications or questions on this topic. Happy coding!

This post is licensed under CC BY 4.0 by the author.