defuss-open-telemetry

Tiny bridge from defuss-style metrics into OpenTelemetry-compatible meters.

Zero runtime dependencies on the OTel SDK - all interfaces are duck-typed. You hand it a meter-like object, and it returns a sink with incrementCounter, recordHistogram, and setGauge.

With a real OpenTelemetry Meter

import { metrics } from "@opentelemetry/api";
import { createOpenTelemetrySink, OtelMeterAdapter } from "defuss-open-telemetry";

const realMeter = metrics.getMeter("my-service");
const sink = createOpenTelemetrySink({
  meter: new OtelMeterAdapter(realMeter),
  prefix: "defuss.orchestrator.",
});

sink.incrementCounter("requests");
sink.recordHistogram("latency_ms", 42);
sink.setGauge("queue_depth", 7);

OtelMeterAdapter bridges the OTel 1.x gauge API difference (see ARCH.md).

Without OTel (no-op)

import { noopTelemetrySink } from "defuss-open-telemetry";

// All calls are silently discarded
noopTelemetrySink.incrementCounter("x");

For testing

import { createOpenTelemetrySink, InMemoryMeter } from "defuss-open-telemetry";

const meter = new InMemoryMeter();
const sink = createOpenTelemetrySink({ meter });

sink.incrementCounter("hits", 3);
console.log(meter.counters.get("hits")); // [{ value: 3, attributes: undefined }]

sink.setGauge("active", 5);
meter.collect(); // triggers gauge callbacks
console.log(meter.gauges.get("active")!.observations); // [{ value: 5, ... }]

API surface

| Export | Purpose | |---------------------------|------------------------------------------------------| | createOpenTelemetrySink | Factory - returns a TelemetrySink from a MeterLike | | OtelMeterAdapter | Wraps a real OTel 1.x Meter into MeterLike | | InMemoryMeter | Test double implementing MeterLike | | noopTelemetrySink | Zero-cost no-op TelemetrySink |

See ARCH.md for design rationale.