/**
 * OTLP/HTTP metrics exporter (core 1.37 observability seam) — DEPENDENCY-FREE. core stays SDK-free and
 * the deployment owns export; rather than pull in the OpenTelemetry SDK (a concern for the intranet
 * mirror + the bun-compiled binary), we periodically snapshot the in-process registry and POST it to an
 * OTLP collector as OTLP/JSON `ExportMetricsServiceRequest`. Enabled only when `OTEL_EXPORTER_OTLP_ENDPOINT`
 * is set; otherwise zero overhead. Prometheus /metrics is unaffected — both can run side by side.
 */
import type { MetricSnapshot } from "./metrics.js";
/** Build the OTLP/JSON metrics payload from a registry snapshot. Pure → unit-testable. */
export declare function buildOtlpPayload(snap: MetricSnapshot, opts: {
    serviceName: string;
    startMs: number;
    nowMs: number;
}): {
    resourceMetrics: {
        resource: {
            attributes: {
                key: string;
                value: {
                    stringValue: string;
                };
            }[];
        };
        scopeMetrics: {
            scope: {
                name: string;
            };
            metrics: unknown[];
        }[];
    }[];
};
export interface OtlpExporterOptions {
    endpoint: string;
    intervalMs: number;
    serviceName: string;
    headers: Record<string, string>;
    fetchImpl?: typeof fetch;
    onError?: (err: unknown) => void;
}
/** Start the periodic push loop (unref'd so it never holds the process open). Returns a stop handle. */
export declare function startOtlpExporter(metrics: {
    snapshot(): MetricSnapshot;
}, opts: OtlpExporterOptions): {
    stop(): void;
};
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