import type * as Log from './internal/Log.js';
/** Tag values a metric backend accepts. */
export type Tags = Record<string, string | number | boolean | undefined | null>;
/**
 * The bounded StatsD-style surface the built-in metric sinks emit to, plus an
 * optional high-cardinality {@link Metrics.analytics} hook. Apps supply a
 * concrete backend — e.g. {@link cloudflare} — so core carries no metrics-vendor
 * dependency. Pass it as `metrics` to `App.create` and the webhook poller/queue
 * handlers.
 */
export type Metrics = {
    /**
     * Optional per-request analytics sink, called once with the request-log entry
     * for every response. Unlike the StatsD `count`/`gauge`/`histogram` surface
     * (which stays low-cardinality), this hook carries the full entry — caller
     * ids, org ids, route, status — for a wide-event store (e.g. ClickHouse).
     * Attach it via {@link cloudflare}'s `analytics` option (or {@link from} for a
     * custom backend); omit it to drop analytics. May be async; `App.create` does
     * not await it.
     */
    analytics?: ((entry: Log.Entry) => Promise<void> | void) | undefined;
    /** Increments a counter; same name+tags are summed. */
    count(name: string, value: number, tags?: Tags): void;
    /** Ships accumulated metrics. */
    flush(): void;
    /** Sets a gauge; last write wins for the same name+tags. */
    gauge(name: string, value: number, tags?: Tags): void;
    /** Records a histogram observation. */
    histogram(name: string, value: number, tags?: Tags): void;
};
/**
 * Creates a {@link Metrics} from a value, type-checking it against the contract.
 * The escape hatch for bringing your own backend (Datadog, Prometheus, …):
 * author the implementation inline and have it validated against {@link Metrics}.
 */
export declare function from<const metrics extends Metrics>(metrics: metrics): metrics;
/** Options for the {@link cloudflare} preset and its backend. */
export declare namespace cloudflare {
    /** Shared context handed to the {@link Options.analytics} factory. */
    type Context = {
        /** Resolved `enabled` flag; the analytics sink should drop events when false. */
        enabled: boolean;
        /** Deployment environment, also added as the `environment` global tag. */
        environment?: string | undefined;
        /** Service name, also added as the `service` global tag. */
        service?: string | undefined;
    };
    type Options = {
        /**
         * Builds the per-request {@link Metrics.analytics} hook from the shared
         * {@link Context}, so the sink reuses `enabled`/`environment`/`service`
         * instead of repeating them. Omit to drop analytics.
         */
        analytics?: ((context: Context) => Metrics['analytics']) | undefined;
        /** Set false (e.g. in local `wrangler dev`) to drop every metric and analytics event. Default true. */
        enabled?: boolean | undefined;
        /** Deployment environment, added as the `environment` global tag and shared with {@link Options.analytics}. */
        environment?: string | undefined;
        /** Service name, added as the `service` global tag and shared with {@link Options.analytics}. */
        service?: string | undefined;
    };
}
/**
 * A Cloudflare Workers {@link Metrics} — pass it as `metrics` to `App.create`
 * and the webhook poller/queue handlers. It buffers metrics and emits them on
 * `flush()` as `cwm-`-prefixed `console.log` lines (one per ≤250 KiB batch) for
 * a Workers Logs → metrics pipeline to scrape; no external dependency.
 */
export declare function cloudflare(options?: cloudflare.Options): Metrics;
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