Unable to read Exception from Aws\Api\Parser\EventParsingIterator

[Luke-Shepp]

Describe the bug

When parsing an API response, it is structured as an Aws\Api\Parser\EventParsingIterator, and parses each event within the iterator when the current element is fetched.

An event type of error is handled:

if ($event['headers'][':message-type'] === 'error') {
    return $this->parseError($event);
}

However, if the event type is exception, a ParserException is thrown:

if ($event['headers'][':message-type'] !== 'event') {
    throw new ParserException('Failed to parse unknown message type.');
}

It's then, without modification of the library code itself, not possible to retrieve the actual exception details from the response. For example, when dumping the event and stream content before the throw, the actual exception is that the Lambda function failed on this occasion:

Expected Behavior

If there's an exception event, with a JSON payload, it should be decoded and returned - instead of throwing an exception with no way to obtain the actual exception/payload details.

Current Behavior

A ParserException is thrown.

Reproduction Steps

In my specific case,

• AWS Bedrock Agent configured with an OpenAPI specification
• Lambda function handling API proxy
• The API call returns a 500 error, or the lambda function fails
• ParserException is thrown when trying to extract data from the response.

Possible Solution

Implement a:

if ($event['headers'][':message-type'] === 'exception') {
    return $this->handleException($event);
}

Additional Information/Context

No response

SDK version used

3.306.7, but is the same logic on the main branch

Environment details (Version of PHP (php -v)? OS name and version, etc.)

php 8.2

[adrianpaiva1]

same issue here

[marcelfolaron]

Can confirm this issue on our end as well. Debugging was quite difficult.

[marcelfolaron]

Any updates on this? It is impossible at times to figure out what the actual issue is. Especially since it could be a simple error returned by the model as in this case (this is the contents of $event['payload']->getContents():

{"message":"The model returned the following errors: tools.0.custom.input_schema: JSON schema is invalid. It must match JSON Schema draft 2020-12 (https://json-schema.org/draft/2020-12). Learn more about tool use at https://docs.anthropic.com/en/docs/tool-use."}

Surfacing the exception message would be quite helpful. For now I added

 if ($event['headers'][':message-type'] === 'exception') {
    if(isset($event['payload']) && $event['payload'] instanceof StreamInterface){
        throw new \Exception($event['payload']->getContents());
    }
    throw new \Exception(var_export($event) ?? 'Failed to get exception payload.');
}

in vendor/aws/aws-sdk-php/src/Api/Parser/EventParsingIterator.php method parseEvent
which seems to work in my use case.

[yenfryherrerafeliz]

Hi all, sorry for the delay on this. I will be looking into this soon.

Thanks!

[stobrien89]

Hi Everyone, #3133 is available as of today's release. Closing this for now, but please let us know if you're still experiencing issues after upgrading.

[github-actions]

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