common.go

package main

import (
	"fmt"
	"sync"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/awserr"
	"github.com/aws/aws-sdk-go/aws/credentials"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/s3"
	"go.uber.org/zap"
)

// checkBucket checks a buckets region.  We use the HeadObject function as this is can be used anonymously and is not
// subject to the buckets policy like GetBucketRegion.  The region is returned in the header of the HTTP response.
func checkBucket(sess *session.Session, detectRegion bool, bucket string, wg *sync.WaitGroup) (svc *s3.S3, err error) {
	if wg != nil {
		defer wg.Done()
	}
	var logger = zap.S()

	svc = s3.New(sess)
	if !detectRegion && sess.Config.Region != nil {
		return svc, nil
	}

	result, err := svc.GetBucketLocation(&s3.GetBucketLocationInput{
		Bucket: aws.String(bucket),
	})

	if err == nil {
		svc = s3.New(sess, &aws.Config{MaxRetries: aws.Int(30),
			Region: aws.String(s3.NormalizeBucketLocation(*result.LocationConstraint))})

		return svc, err
	}

	if aerr, ok := err.(awserr.Error); ok {

		if aerr.Code() == s3.ErrCodeNoSuchBucket {
			fmt.Println(aerr.Message() + ": " + bucket)
			logger.Fatal(aerr.Message())
			return svc, err
		}

		//Try getting the region via head-object.
		svc = s3.New(session.Must(session.NewSession(&aws.Config{
			Credentials: credentials.AnonymousCredentials,
			Region:      sess.Config.Region,
		})))

		req, _ := svc.HeadBucketRequest(&s3.HeadBucketInput{
			Bucket: aws.String(bucket),
		})

		err = req.Send()
		if err != nil {
			fmt.Println(err)

			if aerr, ok := err.(awserr.Error); ok {
				switch aerr.Code() {

				case s3.ErrCodeNoSuchBucket:
					logger.Fatal(aerr.Message())
				default:
					logger.Fatal(aerr.Error())

				}
			} else {
				// Print the error, cast err to awserr.Error to get the Code and
				// Message from an error.
				logger.Fatal(err.Error())
			}
			return svc, err
		} //if

		req.HTTPResponse.Header.Get("X-Amz-Bucket-Region")
		svc = s3.New(sess, &aws.Config{MaxRetries: aws.Int(30),
			Region: aws.String(s3.NormalizeBucketLocation(req.HTTPResponse.Header.Get("X-Amz-Bucket-Region")))})
	}

	return svc, err
}