lib: add tracing support for fetch(undici)

nodesource · Nov 13, 2024 · 62e2f6f · 62e2f6f
1 parent 8696d0a
commit 62e2f6f
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Showing 3 changed files with 101 additions and 2 deletions.
diff --git a/lib/internal/nsolid_diag.js b/lib/internal/nsolid_diag.js
@@ -8,23 +8,114 @@ const {
 } = nsolidApi;
 
 const { now } = require('internal/perf/utils');
+const { contextManager } = require('internal/otel/context');
+const {
+  getApi,
+} = require('internal/otel/core');
+
+const {
+  generateSpan,
+  nsolidTracer,
+} = require('internal/nsolid_trace');
 
 const dc = require('diagnostics_channel');
 
 const {
   kHttpClientAbortCount,
   kHttpClientCount,
+  kSpanHttpClient,
+  kSpanHttpMethod,
+  kSpanHttpReqUrl,
+  kSpanHttpStatusCode,
 } = nsolid_consts;
 
+const undiciFetch = dc.tracingChannel('undici:fetch');
+
+let tracingEnabled = false;
+
+const fetchSubscribeListener = (message, name) => {};
+
+function disableTracing() {
+  undiciFetch.start.unbindStore();
+  dc.unsubscribe('tracing:undici:fetch:start', fetchSubscribeListener);
+}
+
+function enableTracing() {
+  undiciFetch.start.bindStore(contextManager._getALS(), (data) => {
+    const { req } = data;
+    const api = getApi();
+    const tracer = api.trace.getTracer('http');
+    const span = tracer.startSpan(`HTTP ${req.method}`,
+                                  { internal: true,
+                                    kind: api.SpanKind.CLIENT,
+                                    type: kSpanHttpClient });
+    span._pushSpanDataString(kSpanHttpMethod, req.method);
+    span._pushSpanDataString(kSpanHttpReqUrl, req.url);
+    const { spanId, traceId } = span.spanContext();
+    if (span._isSampled()) {
+      req.headers.append('traceparent', `00-${traceId}-${spanId}-01`);
+    } else {
+      req.headers.append('traceparent', `00-${traceId}-${spanId}-00`);
+    }
+
+    return api.trace.setSpan(api.context.active(), span);
+  });
+
+  dc.subscribe('tracing:undici:fetch:start', fetchSubscribeListener);
+}
+
+nsolidTracer.on('flagsUpdated', () => {
+  const next = generateSpan(kSpanHttpClient);
+  if (next && !tracingEnabled) {
+    enableTracing();
+    tracingEnabled = true;
+  } else if (!next && tracingEnabled) {
+    disableTracing();
+    tracingEnabled = false;
+  }
+});
+
 dc.subscribe('undici:request:create', ({ request }) => {
   request[nsolid_tracer_s] = now();
 });
 
-dc.subscribe('undici:request:headers', ({ request }) => {
+dc.subscribe('undici:request:headers', ({ request, response }) => {
   nsolid_counts[kHttpClientCount]++;
   nsolidApi.pushClientBucket(now() - request[nsolid_tracer_s]);
+  if (generateSpan(kSpanHttpClient)) {
+    const api = getApi();
+    const span = api.trace.getSpan(api.context.active());
+    if (span) {
+      span._pushSpanDataUint64(kSpanHttpStatusCode, response.statusCode);
+      if (response.statusCode >= 400) {
+        span.setStatus({ code: getApi().SpanStatusCode.ERROR });
+      }
+    }
+  }
+});
+
+dc.subscribe('undici:request:trailers', ({ request }) => {
+  if (generateSpan(kSpanHttpClient)) {
+    const api = getApi();
+    const span = api.trace.getSpan(api.context.active());
+    if (span) {
+      span.end();
+    }
+  }
 });
 
-dc.subscribe('undici:request:error', () => {
+dc.subscribe('undici:request:error', ({ request, error }) => {
   nsolid_counts[kHttpClientAbortCount]++;
+  if (generateSpan(kSpanHttpClient)) {
+    const api = getApi();
+    const span = api.trace.getSpan(api.context.active());
+    if (span) {
+      span.recordException(error);
+      span.setStatus({
+        code: getApi().SpanStatusCode.ERROR,
+        message: error.message,
+      });
+      span.end();
+    }
+  }
 });
diff --git a/lib/internal/otel/context.js b/lib/internal/otel/context.js
@@ -194,6 +194,10 @@ class AsyncLocalStorageContextManager extends AbstractAsyncHooksContextManager {
     this._asyncLocalStorage.disable();
     return this;
   }
+
+  _getALS() {
+    return this._asyncLocalStorage;
+  }
 }
 
 const contextManager = new AsyncLocalStorageContextManager();

diff --git a/test/parallel/test-bootstrap-modules.js b/test/parallel/test-bootstrap-modules.js
@@ -122,6 +122,10 @@ expected.atRunTime = new Set([
   'NativeModule internal/nsolid_loader',
   'NativeModule internal/nsolid_promise_tracking',
   'NativeModule internal/nsolid_diag',
+  'NativeModule internal/nsolid_trace',
+  'NativeModule internal/otel/api',
+  'NativeModule internal/otel/context',
+  'NativeModule internal/otel/core',
 ]);
 
 if (common.isMainThread) {