macula_metrics (macula v4.2.9)

Node-wide Prometheus-style metric registry for macula-net.

Phase 4.1 — see PLAN_MACULA_NET_PHASE4_1_OBSERVABILITY.md.

Backed by ETS:

?META — {Name, Type, Labels, Help, Buckets}
?VALS — {{counter, Name, LabelVals}, Count}
{{gauge, Name, LabelVals}, Value}
{{hist_bk, Name, LabelVals, I}, Count} (per bucket)
{{hist_sm, Name, LabelVals}, SumMicros}
{{hist_ct, Name, LabelVals}, Count}

Counters and histograms use ets:update_counter/4 which is lock-free per-key; no gen_server roundtrip on the hot path.

Telemetry handlers are attached at start. Hot paths emit via telemetry:execute/3; the handler maps event_name + measurements to counter/histogram updates. Grep for telemetry:execute to find every measurement point.

Gauges are polled (1s) from source-of-truth (ETS sizes).

Summary

Types

label_name/0

label_val/0

label_vals/0

metric_name/0

Functions

gather()

Returns the full metric snapshot in a render-friendly shape.

handle_call(Msg, From, State)

handle_cast(Msg, State)

handle_info(_, State)

handle_telemetry_event(Other, M, Md, Cfg)

inc_counter(Name, LabelVals, N)

init(Opts)

observe(Name, LabelVals, V)

register_counter(Name, Labels, Help)

register_gauge(Name, Labels, Help)

register_histogram(Name, Labels, Help, Buckets)

reset_all()

Wipe every counter / gauge / histogram value. Metadata stays.

set_gauge(Name, LabelVals, V)

start_link()

start_link(Opts)

stop()

terminate(_, State)