feat(unstable): no config npm:@opentelemetry/api integration (denoland#27541)

After this PR, one does not need to import `jsr:@deno/otel` anymore.

Author: lucacasonato

cli/tsc/dts/lib.deno.unstable.d.ts

@@ -1268,16 +1268,15 @@ declare namespace Deno {
    * OpenTelemetry API. This is done using the official OpenTelemetry package
    * for JavaScript:
    * [`npm:@opentelemetry/api`](https://opentelemetry.io/docs/languages/js/).
-   * Deno integrates with this package to provide trace context propagation
-   * between native Deno APIs (like `Deno.serve` or `fetch`) and custom user
-   * code. Deno also provides APIs that allow exporting custom telemetry data
-   * via the same OTLP channel used by the Deno runtime. This is done using the
-   * [`jsr:@deno/otel`](https://jsr.io/@deno/otel) package.
+   * Deno integrates with this package to provide tracing, metrics, and trace
+   * context propagation between native Deno APIs (like `Deno.serve` or `fetch`)
+   * and custom user code. Deno automatically registers the providers with the
+   * OpenTelemetry API, so users can start creating custom traces, metrics, and
+   * logs without any additional setup.
    *
    * @example Using OpenTelemetry API to create custom traces
    * ```ts,ignore
    * import { trace } from "npm:@opentelemetry/api@1";
-   * import "jsr:@deno/[email protected]/register";
    *
    * const tracer = trace.getTracer("example-tracer");
    *

ext/telemetry/telemetry.ts

@@ -1075,6 +1075,11 @@ export function builtinTracer(): Tracer {
   return builtinTracerCache;
 }
 
+// We specify a very high version number, to allow any `@opentelemetry/api`
+// version to load this module. This does cause @opentelemetry/api to not be
+// able to register anything itself with the global registration methods.
+const OTEL_API_COMPAT_VERSION = "1.999.999";
+
 export function bootstrap(
   config: [
     0 | 1,
@@ -1102,6 +1107,19 @@ export function bootstrap(
     default:
       break;
   }
+
+  if (TRACING_ENABLED || METRICS_ENABLED) {
+    const otel = globalThis[SymbolFor("opentelemetry.js.api.1")] ??= {
+      version: OTEL_API_COMPAT_VERSION,
+    };
+    if (TRACING_ENABLED) {
+      otel.trace = TracerProvider;
+      otel.context = ContextManager;
+    }
+    if (METRICS_ENABLED) {
+      otel.metrics = MeterProvider;
+    }
+  }
 }
 
 export const telemetry = {

tests/registry/jsr/@deno/otel/0.0.2/deno.json

@@ -1,7 +1,6 @@
 // Copyright 2018-2025 the Deno authors. MIT license.
 
 import { trace } from "npm:@opentelemetry/[email protected]";
-import "jsr:@deno/[email protected]/register";
 
 const tracer = trace.getTracer("example-tracer");