This is a small utility to fetch the external IP of a client and update an A record in Route53 with the IP value.
I wrote this as a hack for basic dynamic DNS without signing up for anything other than AWS.
$ go get github.com/cgansen/r53dyndns
$ R53_DOMAIN_NAME=example.com R53_HOSTED_ZONE_ID=Z1234EXAMPLE R53_TTL=600 $GOBIN/r53dyndns
2015/10/13 23:17:17 external ip is: 1.2.3.4
2015/10/13 23:17:17 route53 update was a success.
Note: the AWS Go SDK assumes that you have your AWS credentials available in $HOME/.aws/credentials. More complex authentication, including using alternate IAM credentials, is left as an exercise for the reader.
These fine folks made similar tools that do roughly the same job. Sadly, none of them are written in Go.