feat: OpenTelemetry Tracing API and Exporting (#26710)

Initial import of OTEL code supporting tracing. Metrics soon to come.
Implements APIs for https://jsr.io/@deno/otel so that code using
OpenTelemetry.js just works tm.

There is still a lot of work to do with configuration and adding
built-in tracing to core APIs, which will come in followup PRs.

---------

Co-authored-by: Luca Casonato <hello@lcas.dev>

1 files changed, 102 insertions, 0 deletions

diff --git a/cli/tsc/dts/lib.deno.unstable.d.ts b/cli/tsc/dts/lib.deno.unstable.d.ts
index 973a09d92..6234268c3 100644
--- a/cli/tsc/dts/lib.deno.unstable.d.ts
+++ b/cli/tsc/dts/lib.deno.unstable.d.ts
@@ -1225,6 +1225,108 @@ declare namespace Deno {
     export {}; // only export exports
   }
 
+  /**
+   * @category Telemetry
+   * @experimental
+   */
+  export namespace tracing {
+    /**
+     * Whether tracing is enabled.
+     * @category Telemetry
+     * @experimental
+     */
+    export const enabled: boolean;
+
+    /**
+     * Allowed attribute type.
+     * @category Telemetry
+     * @experimental
+     */
+    export type AttributeValue = string | number | boolean | bigint;
+
+    /**
+     * A tracing span.
+     * @category Telemetry
+     * @experimental
+     */
+    export class Span implements Disposable {
+      readonly traceId: string;
+      readonly spanId: string;
+      readonly parentSpanId: string;
+      readonly kind: string;
+      readonly name: string;
+      readonly startTime: number;
+      readonly endTime: number;
+      readonly status: null | { code: 1 } | { code: 2; message: string };
+      readonly attributes: Record<string, AttributeValue>;
+      readonly traceFlags: number;
+
+      /**
+       * Construct a new Span and enter it as the "current" span.
+       */
+      constructor(
+        name: string,
+        kind?: "internal" | "server" | "client" | "producer" | "consumer",
+      );
+
+      /**
+       * Set an attribute on this span.
+       */
+      setAttribute(
+        name: string,
+        value: AttributeValue,
+      ): void;
+
+      /**
+       * Enter this span as the "current" span.
+       */
+      enter(): void;
+
+      /**
+       * Exit this span as the "current" span and restore the previous one.
+       */
+      exit(): void;
+
+      /**
+       * End this span, and exit it as the "current" span.
+       */
+      end(): void;
+
+      [Symbol.dispose](): void;
+
+      /**
+       * Get the "current" span, if one exists.
+       */
+      static current(): Span | undefined | null;
+    }
+
+    /**
+     * A SpanExporter compatible with OpenTelemetry.js
+     * https://open-telemetry.github.io/opentelemetry-js/interfaces/_opentelemetry_sdk_trace_base.SpanExporter.html
+     * @category Telemetry
+     * @experimental
+     */
+    export class SpanExporter {}
+
+    /**
+     * A ContextManager compatible with OpenTelemetry.js
+     * https://open-telemetry.github.io/opentelemetry-js/interfaces/_opentelemetry_api.ContextManager.html
+     * @category Telemetry
+     * @experimental
+     */
+    export class ContextManager {}
+
+    export {}; // only export exports
+  }
+
+  /**
+   * @category Telemetry
+   * @experimental
+   */
+  export namespace metrics {
+    export {}; // only export exports
+  }
+
   export {}; // only export exports
 }