modules, improvements

1. Go Modules supports
2. Authorize with default credentials chain if specific ones are not provided
3. Code cleanup

Signed-off-by: Andrey Klimentyev <[email protected]>

Author: zuzzas

ec2_describe_tags.go

@@ -67,13 +67,17 @@ func main() {
 		instanceID = resp
 	}
 
-	creds := credentials.NewStaticCredentials(awsAccessKey, awsSecretAccessKey, "")
+	var creds *credentials.Credentials
+	if len(awsAccessKey) != 0 || len(awsSecretAccessKey) != 0 {
+		creds = credentials.NewStaticCredentials(awsAccessKey, awsSecretAccessKey, "")
+	}
 
-	svc := ec2.New(session.New(), &aws.Config{Credentials: creds, Region: aws.String(region)})
+	sess, err := session.NewSession(&aws.Config{Credentials: creds, Region: aws.String(region)})
+	svc := ec2.New(sess, &aws.Config{Credentials: creds, Region: aws.String(region)})
 
 	params := &ec2.DescribeInstancesInput{
 		Filters: []*ec2.Filter{
-			&ec2.Filter{
+			{
 				Name: aws.String("instance-id"),
 				Values: []*string{
 					aws.String(instanceID),
@@ -94,7 +98,7 @@ func main() {
 	for idx := range resp.Reservations {
 		for _, inst := range resp.Reservations[idx].Instances {
 			// https: //godoc.org/github.com/awslabs/aws-sdk-go/service/ec2#Instance
-			s := []string{}
+			var s []string
 			for _, tag := range inst.Tags {
 				s = append(s, *tag.Key+kvdelim+*tag.Value)
 			}

go.mod

@@ -0,0 +1,5 @@
+module github.com/hmalphettes/go-ec2-describe-tags
+
+go 1.13
+
+require github.com/aws/aws-sdk-go v1.28.0

go.sum

@@ -0,0 +1,4 @@
+github.com/aws/aws-sdk-go v1.28.0 h1:NkmnHFVEMTRYTleRLm5xUaL1mHKKkYQl4rCd+jzD58c=
+github.com/aws/aws-sdk-go v1.28.0/go.mod h1:KmX6BPdI08NWTb3/sm4ZGu5ShLoqVDhKgpiN924inxo=
+github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af h1:pmfjZENx5imkbgOkpRUYLnmbU7UEFbjtDA2hxJ1ichM=
+github.com/jmespath/go-jmespath v0.0.0-20180206201540-c2b33e8439af/go.mod h1:Nht3zPeWKUH0NzdCt2Blrr5ys8VGpn0CEB0cQHVjt7k=