EventBridge API returns 'InternalFailure' error when 'resources' contain a 'null' value

[julealgon]

Description

When calling IAmazonEventBridge.PutEventsAsync with an event entry having the Resources property initialized to a collection containing a null string, the service returns a generic InternalFailure error containing the message "Internal Service Failure".

The documentation for InternalFailureException indicates it is thrown due to unknown circumstances, however this appears to be a simple input validation gap on the EventBridge backend: if null resource values are not accepted, then they should be validated.

Reproduction Steps

1. Call IAmazonEventBridge.PutEventsAsync with an event containing a null entry in the Resources collection (see example below):

    public class Something
    {
        private readonly IAmazonEventBridge amazonEventBridge;

        public Something(IAmazonEventBridge amazonEventBridge)
        {
            this.amazonEventBridge = amazonEventBridge;
        }

        public async Task PublishEventAsync()
        {
            var request = new PutEventsRequest
            {
                Entries =
                {
                    new PutEventsRequestEntry
                    {
                        Detail = "{}",
                        DetailType = "EventType",
                        Source = "EventSource",

                        // Notice this adds a 'null' element to the collection, which is different than setting the collection to 'null'
                        Resources = { null },
                    },
                },
            };

            var response = await this.amazonEventBridge.PutEventsAsync(request);
        }
    }

2. Observe the returned payload in response:

{
    "Entries": [{
            "ErrorCode": "InternalFailure",
            "ErrorMessage": "Internal Service Failure",
            "EventId": null
        }
    ],
    "FailedEntryCount": 1,
    "ResponseMetadata": {
        "RequestId": "a99c1d6a-d800-4bda-b1b4-f54f3996ef2c",
        "Metadata": {}
    },
    "ContentLength": 108,
    "HttpStatusCode": 200
}

Environment

• SDK Version:
• Package Version: AWSSDK.EventBridge v3.5.4.26
• OS Info: Windows 10
• Build Environment Visual Studio
• Targeted .NET Platform: NetCore 3.1

Resolution

• 👋 I can/would-like-to implement a fix for this problem myself

The problem here appears to be related to input validation on the EventBridge API. Instead of returning an InternalError, which basically means "we have no idea what happened here", it should be validating that none of the entries in Resources is null and returning a more appropriate error and message when that's the case.

The current error might end up causing frustration on developers who for some reason have this value coming from an external place and the resource value there being null.

I stumbled upon this while testing my logic by passing the InvokedFunctionArn value from my lambda to the resources collection. Unfortunatelly, InvokedFunctionArn is always null while testing with the Mock Lambda Tool, which resulted in the resource value being null in the event.

---

This is a 🐛 bug-report

[ashishdhingra]

Hi @julealgon,

Good morning.

While I agree there should be some kind of validation, but I'm not sure this is a valid use case since Resources list need to specify collection of valid resources. The SDK specifies it can be an empty list https://github.com/aws/aws-sdk-net/blob/874768a26b4d6a3f7bf5fd57ac7d94e07a5b3b80/sdk/src/Services/EventBridge/Generated/Model/PutEventsRequestEntry.cs#L108

Kindly note that this is an auto-generated code and I would need to discuss this with development team if this is feasible.

Thanks,
Ashish

[julealgon]

@ashishdhingra

...but I'm not sure this is a valid use case since Resources list need to specify collection of valid resources.

Which is why I did not argue about it being valid. I think it makes sense on your side to consider null entries as invalid as well.

Kindly note that this is an auto-generated code and I would need to discuss this with development team if this is feasible.

Note here that I'm not necessarily suggesting any changes to the client-side autogenerated model, but to the server-side validation logic. My point on this one is that "InternalFailure" is a very cryptic error for such validation problem, and it must be happening exactly because the EventBridge server-side is lacking such validation and it is hitting a "generic fallback" of some sort that assigns it the "InternalFailure" message.

I'm totally with you that attempting to prevent this kind of thing on the client-side is a fool's errand. Just provide a more specific error message and I think that would eliminate the problem as it would indicate to the developer what the issue is and it is a mostly simple fix on the consumer side.

[ashishdhingra]

@ashishdhingra

...but I'm not sure this is a valid use case since Resources list need to specify collection of valid resources.

Which is why I did not argue about it being valid. I think it makes sense on your side to consider null entries as invalid as well.

Kindly note that this is an auto-generated code and I would need to discuss this with development team if this is feasible.

Note here that I'm not necessarily suggesting any changes to the client-side autogenerated model, but to the server-side validation logic. My point on this one is that "InternalFailure" is a very cryptic error for such validation problem, and it must be happening exactly because the EventBridge server-side is lacking such validation and it is hitting a "generic fallback" of some sort that assigns it the "InternalFailure" message.

I'm totally with you that attempting to prevent this kind of thing on the client-side is a fool's errand. Just provide a more specific error message and I think that would eliminate the problem as it would indicate to the developer what the issue is and it is a mostly simple fix on the consumer side.

@julealgon For server-code validation logic, you would need to open a support case for service team. SDK just returns the error returned by service.

[julealgon]

For server-code validation logic, you would need to open a support case for service team. SDK just returns the error returned by service.

Can you direct me to where I can open such case @ashishdhingra? Or perhaps you could redirect them this issue instead?

[ashishdhingra]

For server-code validation logic, you would need to open a support case for service team. SDK just returns the error returned by service.

Can you direct me to where I can open such case @ashishdhingra? Or perhaps you could redirect them this issue instead?

@julealgon This is probably a feature request for service team. Let me try to find that information and get back to you.

[ashishdhingra]

Hi @julealgon,

Just FYI, I have opened an internal ticket with the service team for this issue. Hopefully we could get the reply from the service team soon. Also transferred this issue to shared AWS SDK repository for better management.

Thanks,
Ashish

[ashishdhingra]

P44010896

[ashishdhingra]

@julealgon The issue is fixed by the service team. When executing the AmazonEventBridgeClient.PutEventsAsync() call with PutEventsRequestEntry.Resources containing a null value, we now get proper entry in response with error code InvalidArgument and message Parameter Resource is not valid. Reason: Resource cannot be null..