Initial snapshot - OpenTelemetry demo 2.1.3 -f

1 files changed, 40 insertions, 0 deletions

diff --git a/src/frontend/utils/telemetry/InstrumentationMiddleware.ts b/src/frontend/utils/telemetry/InstrumentationMiddleware.ts
new file mode 100644
index 0000000..ed389af
--- /dev/null
+++ b/src/frontend/utils/telemetry/InstrumentationMiddleware.ts
@@ -0,0 +1,40 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+import { NextApiHandler } from 'next';
+import {context, Exception, Span, SpanStatusCode, trace} from '@opentelemetry/api';
+import { SemanticAttributes } from '@opentelemetry/semantic-conventions';
+import { metrics } from '@opentelemetry/api';
+
+const meter = metrics.getMeter('frontend');
+const requestCounter = meter.createCounter('app.frontend.requests');
+
+const InstrumentationMiddleware = (handler: NextApiHandler): NextApiHandler => {
+  return async (request, response) => {
+    const {method, url = ''} = request;
+    const [target] = url.split('?');
+
+    const span = trace.getSpan(context.active()) as Span;
+
+    let httpStatus = 200;
+    try {
+      await runWithSpan(span, async () => handler(request, response));
+      httpStatus = response.statusCode;
+    } catch (error) {
+      span.recordException(error as Exception);
+      span.setStatus({ code: SpanStatusCode.ERROR });
+      httpStatus = 500;
+      throw error;
+    } finally {
+      requestCounter.add(1, { method, target, status: httpStatus });
+      span.setAttribute(SemanticAttributes.HTTP_STATUS_CODE, httpStatus);
+    }
+  };
+};
+
+async function runWithSpan(parentSpan: Span, fn: () => Promise<unknown>) {
+  const ctx = trace.setSpan(context.active(), parentSpan);
+  return await context.with(ctx, fn);
+}
+
+export default InstrumentationMiddleware;