api: ListBuckets() should have a default region for AWS S3.

[harshavardhana]

Fixes #717

[vadmeste]

LGTM

[donatello]

Comment fix. otherwise lgtm.

[donatello]

s/Default to location to/Default location to/

[donatello]

Perhaps a switch statement would be more natural here.

[harshavardhana]

I tried that.. but it got complex. So an if-condition was easier. In-fact will cleanup to put this under functions for each cases.

[krishnasrinivas]

this would look more readable?:

        if location == "" {                                                                                                                                                                                        
                switch {                                                                                                                                                                                           
                case s3utils.IsAmazonChinaEndpoint(c.endpointURL):                                                                                                                                                 
                        location = "cn-north-1"                                                                                                                                                                    
                case s3utils.IsAmazonGovCloudEndpoint(c.endpointURL):                                                                                                                                              
                        location = "us-gov-west-1"                                                                                                                                                                 
                case c.region != "":                                                                                                                                                                               
                        location = c.region                                                                                                                                                                        
                default:                                                                                                                                                                                           
                        location = "us-east-1"                                                                                                                                                                     
                }                                                                                                                                                                                                  
        }

[harshavardhana]

can you look again @krishnasrinivas @donatello ?

[krishnasrinivas]

as this is a switch with single case you could rather use
if metadata.bucketName != ""

[harshavardhana]

oh yes done.

[krishnasrinivas]

If the user tries to override AmazonChinaEndpoint region then better not auto correct but let it fail naturally as the server will return error. This will make this function simpler as well.

[harshavardhana]

I don't get it.. @krishnasrinivas

[harshavardhana]

This is how it is in getBucketLocation() let me do that as well.

[krishnasrinivas]

actually this is more readable as it is not a if/else situation (and hence switch need not be used):

        func getDefaultLocation(u url.URL, regionOverride string) (location string) {                                                                                                                              
                if s3utils.IsAmazonChinaEndpoint(u) {                                                                                                                                                              
                        return "cn-north-1"                                                                                                                                                                        
                }                                                                                                                                                                                                  
                if s3utils.IsAmazonGovCloudEndpoint(u) {                                                                                                                                                           
                        return "us-gov-west-1"                                                                                                                                                                     
                }                                                                                                                                                                                                  
                if regionOverride != "" {                                                                                                                                                                          
                        return regionOverride                                                                                                                                                                      
                }                                                                                                                                                                                                  
                return "us-east-1"                                                                                                                                                                                 
        }            

[harshavardhana]

Well this is how it was before @krishnasrinivas

[harshavardhana]

Doing it without switch.

[krishnasrinivas]

previously it was if/else @harshavardhana :

        if s3utils.IsAmazonChinaEndpoint(u) {                                                           
                location = "cn-north-1"                                                                 
        } else if s3utils.IsAmazonGovCloudEndpoint(u) {                                                 
                location = "us-gov-west-1"                                                              
        } else if regionOverride != "" {                                                                
                location = regionOverride                                                               
        } else {                                                                                        
                location = "us-east-1"                                                                  
        }