Unknown errors

[alekkova]

Is your feature request related to a problem? Please describe.

LivenessEventKind.Exception has some predefined exceptions:

amplify-swift/AmplifyPlugins/Predictions/AWSPredictionsPlugin/Liveness/Events/LivenessEvent.swift

Lines 41 to 55 in 358699c

	public struct Exception: RawRepresentable, Equatable {
	public var rawValue: String
	public init(rawValue: String) {
	self.rawValue = rawValue
	}
	public static let accessDenied = Self(rawValue: "AccessDeniedException")
	public static let validation = Self(rawValue: "ValidationException")
	public static let internalServer = Self(rawValue: "InternalServerException")
	public static let throttling = Self(rawValue: "ThrottlingException")
	public static let serviceQuotaExceeded = Self(rawValue: "ServiceQuotaExceededException")
	public static let serviceUnavailable = Self(rawValue: "ServiceUnavailableException")
	public static let sessionNotFound = Self(rawValue: "SessionNotFoundException")
	}

Predefined exceptions are translated to a corresponding FaceLivenessSessionError. But all other exceptions are translated to FaceLivenessSessionError.unknown.

amplify-swift/AmplifyPlugins/Predictions/AWSPredictionsPlugin/Liveness/SPI/AWSPredictionsPlugin+Liveness.swift

Lines 71 to 92 in 358699c

	extension FaceLivenessSessionError {
	init(event: LivenessEventKind.Exception) {
	switch event {
	case .accessDenied:
	self = .accessDenied
	case .validation:
	self = .validation
	case .internalServer:
	self = .internalServer
	case .throttling:
	self = .throttling
	case .serviceQuotaExceeded:
	self = .serviceQuotaExceeded
	case .serviceUnavailable:
	self = .serviceUnavailable
	case .sessionNotFound:
	self = .sessionNotFound
	default:
	self = .unknown
	}
	}
	}

When other exceptions happen it is impossible to understand the reason for an error.

User was receiving a FaceLiveness.FaceLivenessDetectionError(code: 0, message: "An unknown error occurred.", recoverySuggestion: "Please open an issue....") and it took way too much effort to prepare and distribute a special build for the user using a modified Amplify package where a InvalidSignatureException exception header value could finally be observed which hinted about the underlying issue.

amplify-swift/AmplifyPlugins/Predictions/AWSPredictionsPlugin/Liveness/Service/FaceLivenessSession.swift

Lines 150 to 152 in 358699c

	} else if let exceptionType = message.headers.first(where: { $0.name == ":exception-type" }) {
	let exceptionEvent = LivenessEventKind.Exception(rawValue: exceptionType.value)
	onServiceException(.init(event: exceptionEvent))

Describe the solution you'd like

Provide better error descriptions and avoid using unknown errors. Providing at least exception header value would already help in understanding the underlying error.

Describe alternatives you've considered

There are no alternatives.

Is the feature request related to any of the existing Amplify categories?

Predictions

Additional context

No response

[phantumcode]

@alekkova Thanks for submitting the issue. We'll investigate and provide updates here.

[phantumcode]

@alekkova The code currently supports all possible exception from LivenessEventKind.Exception. The default unknown is to provide a graceful fallback if or when a new exception type is added from the Rekognition. Are you observing or seeing an exception that is properly handled?

[alekkova]

@phantumcode thank you for looking into it.

We have stumbled on a case where LivenessEventKind.Exception is initialised with a rawValue: "InvalidSignatureException" . This happens here:

amplify-swift/AmplifyPlugins/Predictions/AWSPredictionsPlugin/Liveness/Service/FaceLivenessSession.swift

Lines 150 to 152 in 358699c

	} else if let exceptionType = message.headers.first(where: { $0.name == ":exception-type" }) {
	let exceptionEvent = LivenessEventKind.Exception(rawValue: exceptionType.value)
	onServiceException(.init(event: exceptionEvent))

This leads to a very unclear "unknown error" on client side, which gives no information about the issue at all. I am worried if there are also other exception types that lead to an unknown error on client side.

[phantumcode]

@alekkova This is a bug with the service not properly catching the InvalidSignatureException and returning an AccessDeniedException. A ticket has been created and assigned to the Rekognition service team to fix this issue.

[alekkova]

Thanks @phantumcode. It would also be appreciated if we received more descriptive errors on client side. For example InvalidSignatureException is more descriptive than AccessDeniedException.

[phantumcode]

@alekkova Thanks you for your feedback. Can you submit a feature request to improve the Liveness client side error messages in the Liveness repo https://github.com/aws-amplify/amplify-ui-swift-liveness

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