`telemetry`

(no submodules)

Purpose

Owns the two OTel counters published by @suaveplan/react-midi: react_midi_messages_received_total for parsed inbound messages delivered through port.onMessage, and react_midi_messages_sent_total for outbound messages sent through port.send. Both counters carry a port attribute (the underlying MIDIPort.id) so downstream dashboards can break traffic out by physical device.

The counters are created lazily off the global metrics API; under a NoopSdk (the default in unit tests) the add calls are silent no-ops. Wiring an InMemoryMetricExporter in a host app or test harness lets consumers verify the counter values against expected deltas without coupling to the meter provider details.

Features

Two counters: receive-side and send-side.
Both tagged with port: string to break traffic out by id.
Stable instrument names; usable as Prometheus / OTLP metric ids.
Default NoopMeter makes telemetry safe to call from unit tests.

Usage: Basic

import { recordReceived, recordSent } from "@suaveplan/react-midi";

recordReceived("midi-in-0");
recordSent("midi-out-0");

Usage: Advanced

// In a host that wires an OTLP exporter, the counter values surface
// in the dashboards as react_midi_messages_received_total{port="..."}.
//
// In a unit test you can swap in an InMemoryMetricExporter to assert
// expected deltas without touching the global MeterProvider:
import { MeterProvider } from "@opentelemetry/sdk-metrics";
import { metrics } from "@opentelemetry/api";

const provider = new MeterProvider();
metrics.setGlobalMeterProvider(provider);
// counters now route to provider's readers.

API Reference

messagesReceivedCounter: Counter — increment via the OTel API.
messagesSentCounter: Counter.
recordReceived(portId: string): void — increment receive counter.
recordSent(portId: string): void — increment send counter.

Implementation Notes

The helper functions exist so call sites do not have to remember the attribute key shape. They cost one synchronous Counter.add each; under the default NoopMeter provider this is genuinely free (the meter API short-circuits a no-op call into a single property lookup).

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telemetry