startup fails because agent looks up default listen hostname (localhost) to the local DNS

[Dieterbe]

latest version in git currently, when trying to start it, this happens:

./dist/synthetic-monitoring-agent -api-server-address synthetic-monitoring-grpc-eu-west.grafana.net:443 -api-token <redacted>
E: listen tcp: lookup localhost on 217.27.32.196:53: no such host

note that:

./dist/synthetic-monitoring-agent --help
Usage of synthetic-monitoring-agent:
(...)
  -listen-address string
    	listen address (default "localhost:4050")
(...)

as a workaround, passing this flag makes it work: -listen-address 127.0.0.1:4050

i don't think 'localhost' should be resolved via dns, though i don't remember the exact mechanics behind this. should we DNS lookup any hostname that is not in /etc/hosts ?
i notice that my /etc/hosts contains this:

# Static table lookup for hostnames.
#
# See hosts(5) for details.
#
# 127.0.0.1       localhost.localdomain   localhost

i expected my system to not have the localhost entry commented out, so perhaps this is a system issue on my end.

[Dieterbe]

uncommenting the line in /etc/hosts makes it work. it looks like this was a misconfiguration on my system (that an earlier version of the agent handled gracefully somehow)