vmstats

vmstats is a tiny Erlang app that gathers metrics on the Erlang VM and sends them to a configurable sink (e.g., StatsD).

The following is a list of the possible options for the configuration of the vmstats app:

sink - (module) a module that implements the vmstats_sink behaviour; vmstats metrics will be collected through this module.
base_key - (string) every metric name is prepended with this base key. Defaults to "vmstats".
key_separator - (char) used as a separator between the parts of metric keys. Defaults to $..
interval - (integer) the time (in milliseconds) between metric gatherings. Defaults to 1000 (1s).
sched_time - (boolean) whether to gather statistics about scheduler wall time. Defaults to true.
memory_metrics - (proplist of metric and key) what fields to collect statistics for. Available fields can be found here. Default list is [{total, total}, {processes_used, procs_used}, {atom_used, atom_used}, {binary, binary}, {ets, ets}].

vmstats sinks must implement the vmstats_sink behaviour. This behaviour only specifies one function:

-callback collect(Type :: counter | gauge | timing,
                  Key :: iodata(),
                  Value :: term()) -> ok.

I was basing myself on ‘master’ and stuff started breaking!

That’s because you should use tags for stable versions instead! The changelog should let you know what to expect.