Error reading COMPLETION field as JSON (botocore type) response from BEDROCK Agent

Question

Hi All,
I have configured an agent in bedrock that invokes a LAMBDA function. Everything works fine.

The problem I'm having is that I want to publish the agent to an EC2 + IIS + Flask + Python.

The service manages to consume and respond, however, when I want to read the COMPLETION field where the Model's response is, I cannot read it correctly.

Here is the python code, if you can help me I would greatly appreciate it.

from flask import Flask, request, jsonify
import json
import logging
import uuid 
import boto3
import asyncio
import botocore.session
from botocore.exceptions import ClientError
from botocore.eventstream import EventStream

response = client.invoke_agent(
            agentId='AAAAAAAAAAAAAAAAA',
            agentAliasId=agent_alias_id,
            sessionId=session_id,
            inputText=prompt,
            endSession=True,
            enableTrace=True
        )

if 'completion' in response:
            event_stream = response['completion']
            
             response_parts = []
            for event in event_stream:
                if 'data' in event:
                    response_data = event['data'].decode('utf-8')
                    
                    print("Evento de respuesta:", response_data)

response_parts.append(response_data)

# Unir todos los fragmentos de respuesta en un solo texto
            final_response = ''.join(response_parts)
        logging.debug(f"Response from COMPLETION: {response.get("completion")}")

return jsonify({"result": final_response})

Thanks

re:Post Agent · Answer

The issue you're experiencing is likely related to how you're handling the 'completion' field in the response from the Bedrock Agent. The 'completion' field is actually an EventStream object, not a JSON structure, which is why you're having trouble reading it directly.

To properly handle the response, you should iterate over the EventStream object and process each chunk of data. Here's how you can modify your code to correctly read the completion:

1. First, check if 'completion' is in the response.
2. If it is, iterate over the EventStream object.
3. For each event, look for a 'chunk' key which contains the actual response data.
4. Decode the bytes in the chunk and append it to your response.

Here's an example of how you could modify your code:

```python
if 'completion' in response:
    completion = ""
    for event in response['completion']:
        if 'chunk' in event:
            chunk = event['chunk']
            if 'bytes' in chunk:
                completion += chunk['bytes'].decode('utf-8')
    
    logging.debug(f"Response from COMPLETION: {completion}")
    return jsonify({"result": completion})
```

This approach should allow you to properly read and process the response from the Bedrock Agent. Remember to handle potential exceptions and edge cases, such as empty responses or unexpected data formats.

Also, make sure you have the latest version of boto3 installed, as older versions might have issues with certain Bedrock operations. If you continue to experience problems, you may want to enable more detailed logging or tracing to get a better understanding of the exact response structure you're receiving from the Bedrock Agent.  
**Sources**  
[Error raised while calling invoke agent operation | AWS re:Post](https://repost.aws/questions/QUa2yZi8PhT1S-QkZMDVlnrg/error-raised-while-calling-invoke-agent-operation)  
[Boto3 dependencyFailedException error when calling the InvokeAgent operation: Access denied when calling Bedrock | AWS re:Post](https://repost.aws/questions/QUeVcpLqqzQNSc6OYmYU2nZA/boto3-dependencyfailedexception-error-when-calling-the-invokeagent-operation-access-denied-when-calling-bedrock)  
[Bedrock agent invokation does not return "returnControl" element | AWS re:Post](https://repost.aws/questions/QUgoXeuSq3TH-myu_FSxSQWg/bedrock-agent-invokation-does-not-return-returncontrol-element)

Error reading COMPLETION field as JSON (botocore type) response from BEDROCK Agent

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