Can't get the final response in a waiter if it is failed

[abrooksv]

Describe the Feature

Expose the last response to the Exception thrown from waiters on failure

Is your Feature Request related to a problem?

Yes, in the cases where the payload of the response triggers a waiter failure, it is impossible to make a decision based on the failure.

I.e.

1. Create change set that will be empty
2. Use CFN waiter waitUntilChangeSetCreateComplete
3. Waiter throws SdkClientException with `The SDK waiter transitions the waiter to be failed in the case of no changes in the change set.
4. No way to determine the cause of the failure due to SdkResponse is not set in the SdkClientException.
   1. In other words, did the change set fail to be created due to bad template, or did it fail due to no changes. One should be terminal failure, the other treated as no-op and skipped by my code.

Proposed Solution

Change Waiter to have a WaiterException that extends SdkClientException. It should have the response that triggered the failure state attached, if possible (i.e. not a timeout)

Describe alternatives you've considered

Additional Context

// Copyright 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

import software.amazon.awssdk.services.cloudformation.CloudFormationClient;

public class Repro {
    public static void main(String[] args) {
        String template = "AWSTemplateFormatVersion: '2010-09-09'\n"
                          + "Resources:\n"
                          + "  LogGroup:\n"
                          + "    Type: AWS::Logs::LogGroup\n";

        String stackName = "SomeStack";
        String changeSetName = "SomeName";

        CloudFormationClient cfnClient = CloudFormationClient.create();
        cfnClient.createStack(builder -> builder.stackName(stackName).templateBody(template));

        cfnClient.waiter().waitUntilStackCreateComplete(builder -> builder.stackName(stackName));

        cfnClient.createChangeSet(builder -> builder.stackName(stackName).changeSetName(changeSetName).templateBody(template));
        System.out.println(cfnClient.waiter().waitUntilChangeSetCreateComplete(builder -> builder.stackName(stackName).changeSetName(changeSetName)));
    }
}

Value of responseOrException passed into software.amazon.awssdk.core.internal.waiters.WaiterExecutor#evaluate:

responseOrException = {Either@4177} 
 left = {Optional@4182} "Optional[DescribeChangeSetResponse(ChangeSetName=SomeName, ChangeSetId=arn:aws:cloudformation:us-west-2:****:changeSet/SomeName/e24d90df-272a-4aba-a2eb-6b948f97b2ba, StackId=arn:aws:cloudformation:us-west-2:****:stack/SomeStackName/3500f520-61a7-11eb-82f2-0a1b1472165f, StackName=SomeStackName, CreationTime=2021-01-28T20:27:45.233Z, ExecutionStatus=UNAVAILABLE, Status=FAILED, StatusReason=The submitted information didn't contain changes. Submit different information to create a change set., NotificationARNs=[], RollbackConfiguration=RollbackConfiguration(), Capabilities=[], Changes=[], IncludeNestedStacks=false)]"
 right = {Optional@4183} "Optional.empty"

• I may be able to implement this feature request

Your Environment

• AWS Java SDK version used:
• JDK version used:
• Operating System and version:

[abrooksv]

Side feature request:

Same request but for this method:

    public SdkClientException noneMatchException(Either<T, Throwable> responseOrException) {
        return responseOrException.map(
            r -> SdkClientException.create("No acceptor was matched for the response"),
            t -> SdkClientException.create("An exception was thrown and did not match any "
                                           + "waiter acceptors", t));
    }

If we enter case 'r', it would be nice to have 'r' attached so it can be logged and reported without needing remote debugging or wire logs.

[debora-ito]

Acknowledged!

[zoewangg]

The side feature request is implemented as part of #2462

[bhoradc]

Hi @abrooksv,

Thanks for the feature request and for the detailed reproduction steps.

As of PR #5230, the exception thrown when a waiter transitions to a failure state now includes the reason in its message. Specifically which acceptor matched and the parameter/value that triggered the failure.

We don't currently plan to attach the full SdkResponse object to the exception, so we're closing this as addressed by the message improvement. Thanks again.

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