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Implementing model fallbacks

To guarantee 24/7 service, TrailBlaze needs to fall back to a lighter model when Claude is unavailable. Implement a fallback from Claude to Nova Text Lite when encountering issues, to ensure continuous service to the travel app.

The json and boto3 libraries, and the bedrock client, are preloaded.

This exercise is part of the course

Introduction to Amazon Bedrock

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Exercise instructions

  • Wrap the primary Claude model call in a try block.
  • In the except block, handle errors using ClientError and call the Nova Text Lite model.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

def process_with_fallback(prompt):
    # Handle errors with a try-except block
    ____:
        response = bedrock.invoke_model(
          modelId="anthropic.claude-3-5-sonnet-20240620-v1:0",
          body=json.dumps({"anthropic_version": "bedrock-2023-05-31", "max_tokens": 100,
                           "messages": [{"role": "user", "content": [{"type": "text", "text": prompt}]}]}))
        return json.loads(response["body"].read().decode())["content"][0]["text"]
    except ____:
        fallback = bedrock.invoke_model(
            modelId="amazon.nova-lite-v1:0",
            body=json.dumps({"messages": [{"role": "user", "content": [{"text": prompt}]}]}))
        return json.loads(fallback["body"].read().decode())["output"]["message"]["content"][0]["text"]

print(process_with_fallback("What are the best destinations in Australia for kayaking?"))
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