This project is a proof-of-concept which demonstrates incorrect behavior with Golang's DNS resolver & connection re-use with the http client.

If you execute run.sh, then following happens:

1. two interfaces eth10 and eth11 on 10.0.0.1 and 10.0.0.2 are created respectively
2. go run's the dns.go main
3. go run's the dns.go main with --close-idle-conns flag set
4. cleans up the two interfaces

If you execute and see the message failed test in the first half of the output, the bug occurred.

The bug demonstrated in the dns.go is the following:

A DNS server is started on :8053 and it contains a single A record for foo.service. in 10.0.0.1. The default go resolver is switched on and the resolver dialer is set to point to the :8053 dns server.

Then an HTTP server is started on 10.0.0.1:8080, and a second HTTP server is started on 10.0.0.2.:8080.

Finally, an HTTP request is made to the A address, foo.service:8080 and the contents of the response is printed. The A record of foo.service. is updated to point to 10.0.0.2. Then an HTTP request is made again to the A address, foo.service:8080. If Go does the right thing, it will hit the HTTP server on 10.0.0.2:8080 and exit 0. If Go does the wrong thing, it will hit the first HTTP server on 10.0.0.1:8080 and exit 1.

Project Maintainers

• @cnmcavoy

Code of Conduct

This project is governed by the Contributor Covenant v 1.4.1.

License

This project uses the Apache 2.0 license.