Amazon ECS Service configuration return exactly 1 result, but got > '0'

We have not been able to identify an bug in our code base right away, here's what's seemingly happening:

In order to append progress messages to the Bamboo build log, we need to call the DescribeServices API action before the call to the actual UpdateService API action, and the exception is thrown if and only if the targeted service cannot be found.

So at first glance there may be a subtle configuration issue, which happens to me every now and then when using Bamboo variables to reference resources from a preceding task, where it is easy to accidentally copy and paste the wrong variable name for example.

An incorrect reference in any of the following parameters of the Amazon ECS Service task's Update Service action would yield the resp. task action to fail with the error message at hand, because the DescribeServices API call in itself would succeed, yet fail to identify the target service:

• Connector
• Region
• Service Name

For example, I've just reproduced the problem by using a non existing service name:

24-Oct-2019 17:37:05    Starting task 'Update sample ECS service (w/ ELB) - 2 instances' of type 'net.utoolity.atlassian.bamboo.tasks-for-aws:aws.ecs.service'
24-Oct-2019 17:37:05    Setting maxErrorRetry=7 and awaitTransitionInterval=15000
24-Oct-2019 17:37:05    Using session credentials provided by Identity Federation for AWS app (connector variable: 6f6fc85d-4ea5-43ce-8e70-25aba33a5fda).
24-Oct-2019 17:37:05    Selecting region eu-west-1
24-Oct-2019 17:37:05    Updating service 'NOT-A-SERVICE' on cluster 'TAWS-IT270-100-ubot':
24-Oct-2019 17:37:06    Failed to fetch resource from AWS!
24-Oct-2019 17:37:06    java.lang.RuntimeException: Expected DescribeServiceRequest for service 'NOT-A-SERVICE' to return exactly 1 result, but got '0'
...

Granted, the error message is not exactly helpful here, and we need to think about how to better handle this log pattern across our various tasks - the actual UpdateServiceAPI action would yield the much more appropriate ServiceNotFoundException exception in this scenario.

So assuming 'my-service' has been up and running before calling the 'Update Service' task action, can you please check whether the log from your failing Bamboo build may indicate this particular problem, for example by targeting another region by chance?

I could solve the issue by using a Shell Script Task and wrote a aws-cli command after exporting the keys. This workaround solved the issue:

aws ecs update-service --cluster my-cluster --service my-service --task-definition my-task-definition

So the AWS ECS is working fine and it should be a bug or misconfiguration in the Bamboo module.

But as mentioned in the other answer, the best approach would be to check if the configuration is correct.