servicediscovery compatability issue with localstack

[codefromthecrypt]

Acknowledgements

• I have searched (https://github.com/aws/aws-sdk/issues?q=is%3Aissue) for past instances of this issue
• I have verified all of my SDK modules are up-to-date (you can perform a bulk update with go get -u github.com/aws/aws-sdk-go-v2/...)

Describe the bug

DiscoverInstances prefixes "data-" to the hostname, rendering localhost (specifically localstack) tests useless, as the hostname "data-localhost" doesn't exist.

Expected Behavior

I would like to use all servicediscovery functions. I'm not sure why others work and DiscoverInstances specifically does this

Current Behavior

I end up with an error like this:

2024-03-14T12:39:51.350703Z	error	unable to refresh Cloud Map cache due to error, using existing cache: error retrieving instance list from Cloud Map for "1" in "testns": operation error ServiceDiscovery: DiscoverInstances, https response error StatusCode: 0, RequestID: , request send failed, Post "http://data-localhost:32957/": dial tcp: lookup data-localhost: no such host

Reproduction Steps

localstack requires an authenticated docker image (localstack-pro) to run, so probably reproduction won't help as much, but the command that fails looks like this:

	instOutput, err := client.DiscoverInstances(ctx, &servicediscovery.DiscoverInstancesInput{ServiceName: svc.Name, NamespaceName: ns.Name})
	if err != nil {
		return nil, errors.Wrapf(err, "error retrieving instance list from Cloud Map for %q in %q", *svc.Name, *ns.Name)
	}

Possible Solution

maybe there is a way to avoid this part of the stack. I don't mind a workaround for testing.

Additional Information/Context

where the prefix happens: https://github.com/aws/aws-sdk-go-v2/blob/main/service/servicediscovery/api_op_DiscoverInstances.go#L193

AWS Go SDK V2 Module Versions Used

	github.com/aws/aws-sdk-go-v2 v1.25.3
	github.com/aws/aws-sdk-go-v2/config v1.27.7
	github.com/aws/aws-sdk-go-v2/credentials v1.17.7
	github.com/aws/aws-sdk-go-v2/service/servicediscovery v1.29.2

Compiler and Version used

go version go1.22.1 darwin/arm64

Operating System and version

macOS 14.4

[lucix-aws]

The AWS SDKs are designed for and are only guaranteed to work against the public AWS services. The servicediscovery service apparently uses data- as a host prefix for certain operations.

If you're using an alternative implementation of the service that doesn't work this way, you can technically remove the EndpointHostPrefix middleware from the Finalize step, though I can't promise that won't cause other issues:

svc := servicediscovery.NewFromConfig(cfg, func (o *servicediscovery.Options) {
    o.APIOptions = append(o.APIOptions, func (stack *middleware.Stack) error {
        // this technically returns an error if the middleware doesn't exist, and on some servicediscovery
        // ops that IS the case, but we don't care
        stack.Finalize.Remove("EndpointHostPrefix")
        return nil
    })
})

[codefromthecrypt]

Thanks for the workaround.

An aside which may or may not change your opinion on handling this. I found out about this approach through work of an AWS employee. It could make sense to make testing possible as attempted here in java by @hariohmprasath awspring/spring-cloud-aws#506 Basically, go shouldn't have a harder time than java imho, but up to you

[codefromthecrypt]

also thanks so much for how fast you got me going. I had the luxury of waking up and able to progress. champion stuff!