Add static opsworks endpoint

[catsby]

AWS OpsWorks has a single endpoint: opsworks.us-east-1.amazonaws.com and
only supports HTTPS requests. While the region is a thing you can configure when you setup your session, setting it to anything but us-east-1 will fail.

Given this script:

package main

import (
    "log"

    "github.com/aws/aws-sdk-go/aws"
    "github.com/aws/aws-sdk-go/aws/session"
    "github.com/aws/aws-sdk-go/service/opsworks"
)

func main() {
    log.Println("OK start")
    svc := opsworks.New(session.New())
    req := &opsworks.AttachElasticLoadBalancerInput{
        ElasticLoadBalancerName: aws.String("terraform-asg-deployment-example"),
        LayerId:                 aws.String("c5d45635-4cde-4cb6-9f62-b48036cd5dd0"),
    }

    r, err := svc.AttachElasticLoadBalancer(req)

    if err != nil {
        log.Printf("\n\terr: %s\n", err)
    }

    if r != nil {
        log.Printf("R: %s\n", r)
    }
}

You'll get an error if AWS_REGION is anything but us-east-1:

    err: RequestError: send request failed
caused by: Post https://opsworks.us-west-2.amazonaws.com/: dial tcp: lookup opsworks.us-west-2.amazonaws.com: no such host

This PR adds opsworks to the endpoints.json so that by default you'll get the correct region. At least, in my limited testing it has.

I've ran the above script successfully after running make gen-endpoints and make build in the root of the SDK.

Suggestions for a better way welcome!

[jasdel]

Thanks for reporting the missing endpoint mapping @catsby. This looks good. I'll regenerate the endpoints_map.go and merge in this change.

[jasdel]

Hi @catsby after taking a deeper look into this issue the SDK's intentionally do not provide this functionality for Opsworks and similar service that are only present in us-east-1. Adding this override would prevent OpsWorks from expanding to additional regions in the future. Because of this we won't be able to pull in this change.

[jasdel]

Thanks a lot for the PR and sorry we cannot take pull it in. But to maintain forward compatibility with potential service expansion we don't want to add logic automatically aliasing the region for this service.

[catsby]

Fair enough, I understand the reasoning to not merge it.

As a counter point, it is less than ideal that I can rely on the sdk to automatically pick up my credentials from the environment (including default region), only to learn that in order to use OpsWorks I had to explicitly configure the connection to use us-east-1.

Less than ideal, but not the end of world 😄

Thanks!

[catsby]

Follow up: My specific less than ideal comment is mostly because the error message I got was dial tcp: lookup opsworks.us-west-2.amazonaws.com: no such host, which at first read made me think there was a problem with the service. Only after some debugging did I think to check AWS's endpoints documentation and decipher that I was hitting a bad / nonexistent endpoint.

Still, not a huge deal I suppose. Thanks again

[jasdel]

@catsby thanks for your feedback. Improving the way these error message to be more specific would definitely clarify why the request failed, and how to resolve it be very nice.

I think this might be a good feature to add better error messaging in this case. Off hand I think we could accomplish this by combining a list of known supported regions with this error message. We wouldn't want to outright block the unsupported region request in case the service has added support for that and the user hasn't updated their SDK. The list of known regions would be needed to ensure that if there actually are routing or connection errors false negative errors won't be reported.

[catsby]

Understandable @jasdel , thanks 😄