Hostname determines the hostname to use from the "COLLECTD_HOSTNAME" environment variable and falls back to os.Hostname() if it is unset.

Interval determines the default interval from the "COLLECTD_INTERVAL" environment variable.

NewExecutor returns a pointer to a new Executor object.

Putval is the dispatcher used by the exec package to print ValueLists.

Executor holds one or more callbacks which are called periodically.