From c5f8770f0f8fd90459e35a829e18176c808cb0fc Mon Sep 17 00:00:00 2001
From: Dipper30 <ddddipper30@gmail.com>
Date: Fri, 16 Jan 2026 16:16:11 +0800
Subject: [PATCH 1/9] feat: support fetch clientOptions interceptors

---
 lib/core/fetch_factory.js                     |  19 ++-
 test/fixtures/apps/fetch-tracer/app.js        |  72 +++++++++++
 test/fixtures/apps/fetch-tracer/app/router.js |  17 +++
 .../fetch-tracer/config/config.default.js     |   6 +
 test/fixtures/apps/fetch-tracer/package.json  |   3 +
 test/lib/core/fetch_tracer.test.js            | 113 ++++++++++++++++++
 6 files changed, 228 insertions(+), 2 deletions(-)
 create mode 100644 test/fixtures/apps/fetch-tracer/app.js
 create mode 100644 test/fixtures/apps/fetch-tracer/app/router.js
 create mode 100644 test/fixtures/apps/fetch-tracer/config/config.default.js
 create mode 100644 test/fixtures/apps/fetch-tracer/package.json
 create mode 100644 test/lib/core/fetch_tracer.test.js

diff --git a/lib/core/fetch_factory.js b/lib/core/fetch_factory.js
index 971bf941b6..9225118a57 100644
--- a/lib/core/fetch_factory.js
+++ b/lib/core/fetch_factory.js
@@ -14,14 +14,23 @@ if (mainNodejsVersion >= 20) {
     FetchFactory = urllib4.FetchFactory;
     debug('urllib4 enable');
 
-
-    fetch = function fetch(url, init) {
+    fetch = function(url, init) {
       if (!fetchInitialized) {
         const clientOptions = {};
         if (this.config.httpclient?.lookup) {
           clientOptions.lookup = this.config.httpclient.lookup;
         }
         FetchFactory.setClientOptions(clientOptions);
+
+        // Support custom interceptors via dispatcher.compose
+        // Must be set after setClientOptions because setClientOptions resets dispatcher
+        // interceptors is an array of interceptor functions that follow undici's dispatcher API(undici have not supported clientOptions.interceptors natively yet)
+        if (this.config.httpclient?.interceptors) {
+          const interceptors = this.config.httpclient.interceptors;
+          const originalDispatcher = FetchFactory.getDispatcher();
+          FetchFactory.setDispatcher(originalDispatcher.compose(interceptors));
+        }
+
         fetchInitialized = true;
       }
       return FetchFactory.fetch(url, init);
@@ -41,6 +50,12 @@ if (mainNodejsVersion >= 20) {
         }
         ssrfFetchFactory = new FetchFactory();
         ssrfFetchFactory.setClientOptions(clientOptions);
+
+        if (this.config.httpclient?.interceptors) {
+          const interceptors = this.config.httpclient.interceptors;
+          const originalDispatcher = ssrfFetchFactory.getDispatcher();
+          ssrfFetchFactory.setDispatcher(originalDispatcher.compose(interceptors));
+        }
       }
       return ssrfFetchFactory.fetch(url, init);
     };
diff --git a/test/fixtures/apps/fetch-tracer/app.js b/test/fixtures/apps/fetch-tracer/app.js
new file mode 100644
index 0000000000..96c37e06f8
--- /dev/null
+++ b/test/fixtures/apps/fetch-tracer/app.js
@@ -0,0 +1,72 @@
+const assert = require('assert');
+
+const TRACE_ID = Symbol('TRACE_ID');
+const RPC_ID = Symbol('RPC_ID');
+
+// Simple Tracer implementation
+class Tracer {
+  constructor(traceId, rpcId = '0') {
+    this.traceId = traceId;
+    this._rpcId = rpcId;
+    this._rpcIdSeq = 0;
+  }
+
+  get rpcId() {
+    return this._rpcId;
+  }
+
+  get rpcIdPlus() {
+    return `${this._rpcId}.${++this._rpcIdSeq}`;
+  }
+}
+
+module.exports = class TracerApp {
+  constructor(app) {
+    this.app = app;
+    assert(app.config);
+    // Expose Tracer class for testing
+    app.Tracer = Tracer;
+  }
+
+  configWillLoad() {
+    // Setup tracer interceptor using interceptors config
+    this.app.config.httpclient = this.app.config.httpclient || {};
+    if (!this.app.FetchFactory) {
+      return;
+    }
+    const tracerConfig = this.app.config.tracer;
+    const HTTP_HEADER_TRACE_ID_KEY = tracerConfig.HTTP_HEADER_TRACE_ID_KEY.toLowerCase();
+    const HTTP_HEADER_RPC_ID_KEY = tracerConfig.HTTP_HEADER_RPC_ID_KEY.toLowerCase();
+
+    this.app.config.httpclient.interceptors = [
+      dispatch => {
+        const app = this.app;
+        return async function tracerInterceptor(opts, handler) {
+          const tracer = app.currentContext?.tracer;
+          let traceId;
+          let rpcId;
+
+          try {
+            if (tracer) {
+              traceId = opts.headers[HTTP_HEADER_TRACE_ID_KEY] = tracer.traceId;
+              rpcId = opts.headers[HTTP_HEADER_RPC_ID_KEY] = tracer.rpcIdPlus;
+            }
+          } catch (e) {
+            e.message = '[egg-tracelog] set tracer header failed: ' + e.message;
+            app.logger.warn(e);
+          }
+
+          try {
+            return await dispatch(opts, handler);
+          } finally {
+            const opaque = handler.opaque;
+            if (opaque) {
+              opaque[TRACE_ID] = traceId;
+              opaque[RPC_ID] = rpcId;
+            }
+          }
+        };
+      },
+    ];
+  }
+};
diff --git a/test/fixtures/apps/fetch-tracer/app/router.js b/test/fixtures/apps/fetch-tracer/app/router.js
new file mode 100644
index 0000000000..7572256147
--- /dev/null
+++ b/test/fixtures/apps/fetch-tracer/app/router.js
@@ -0,0 +1,17 @@
+module.exports = app => {
+  app.get('/test', async ctx => {
+    // Mock a tracer on the context using the Tracer class
+    ctx.tracer = new app.Tracer('test-trace-id-123', '0');
+
+    // Store the current context so fetch can access it
+    app.currentContext = ctx;
+
+    // Make a fetch request
+    const response = await app.fetch(ctx.query.url);
+
+    ctx.body = {
+      status: response.status,
+      ok: response.ok,
+    };
+  });
+};
diff --git a/test/fixtures/apps/fetch-tracer/config/config.default.js b/test/fixtures/apps/fetch-tracer/config/config.default.js
new file mode 100644
index 0000000000..a4ced7edeb
--- /dev/null
+++ b/test/fixtures/apps/fetch-tracer/config/config.default.js
@@ -0,0 +1,6 @@
+exports.keys = 'test key';
+
+exports.tracer = {
+  HTTP_HEADER_TRACE_ID_KEY: 'x-trace-id',
+  HTTP_HEADER_RPC_ID_KEY: 'x-rpc-id',
+};
\ No newline at end of file
diff --git a/test/fixtures/apps/fetch-tracer/package.json b/test/fixtures/apps/fetch-tracer/package.json
new file mode 100644
index 0000000000..b4f4aaca1d
--- /dev/null
+++ b/test/fixtures/apps/fetch-tracer/package.json
@@ -0,0 +1,3 @@
+{
+  "name": "fetch-tracer"
+}
diff --git a/test/lib/core/fetch_tracer.test.js b/test/lib/core/fetch_tracer.test.js
new file mode 100644
index 0000000000..051851d167
--- /dev/null
+++ b/test/lib/core/fetch_tracer.test.js
@@ -0,0 +1,113 @@
+const assert = require('node:assert');
+const http = require('http');
+const utils = require('../../utils');
+
+describe('test/lib/core/fetch_tracer.test.js', () => {
+  const version = utils.getNodeVersion();
+  if (version < 20) return;
+
+  let app;
+  let mockServer;
+  let receivedHeaders;
+
+  before(async () => {
+    // Create a mock server to capture headers
+    mockServer = http.createServer((req, res) => {
+      receivedHeaders = req.headers;
+      res.writeHead(200, { 'Content-Type': 'application/json' });
+      res.end(JSON.stringify({ ok: true }));
+    });
+
+    await new Promise(resolve => {
+      mockServer.listen(0, '127.0.0.1', resolve);
+    });
+
+    app = utils.app('apps/fetch-tracer');
+    await app.ready();
+  });
+
+  after(() => {
+    if (mockServer?.listening) {
+      mockServer.close();
+    }
+  });
+
+  afterEach(() => {
+    receivedHeaders = null;
+  });
+
+  it('should add tracer headers when fetch is called', async () => {
+    const port = mockServer.address().port;
+    const targetUrl = `http://127.0.0.1:${port}/mock`;
+
+    const response = await app.httpRequest()
+      .get('/test')
+      .query({ url: targetUrl })
+      .expect(200);
+
+    assert.strictEqual(response.body.status, 200);
+    assert.strictEqual(response.body.ok, true);
+
+    // Verify tracer headers were added with incremented rpcId
+    assert.strictEqual(receivedHeaders['x-trace-id'], 'test-trace-id-123');
+    assert.strictEqual(receivedHeaders['x-rpc-id'], '0.1'); // rpcIdPlus increments from 0
+  });
+
+  it('should work when tracer is not set', async () => {
+    // Clear currentContext
+    app.currentContext = null;
+
+    const port = mockServer.address().port;
+    const targetUrl = `http://127.0.0.1:${port}/mock`;
+
+    const response = await app.fetch(targetUrl);
+
+    assert.strictEqual(response.status, 200);
+
+    // Verify no tracer headers when tracer is not set
+    assert.strictEqual(receivedHeaders['x-trace-id'], undefined);
+    assert.strictEqual(receivedHeaders['x-rpc-id'], undefined);
+  });
+
+
+  it('should handle fetch before configDidLoad completes', async () => {
+    // Test that lazy initialization preserves interceptors set in configDidLoad
+    const port = mockServer.address().port;
+    const targetUrl = `http://127.0.0.1:${port}/mock`;
+
+    const ctx = app.mockContext();
+    ctx.tracer = new app.Tracer('early-trace-id', '0.1');
+    app.currentContext = ctx;
+
+    const response = await app.fetch(targetUrl);
+
+    assert.strictEqual(response.status, 200);
+    assert.strictEqual(receivedHeaders['x-trace-id'], 'early-trace-id');
+    assert.strictEqual(receivedHeaders['x-rpc-id'], '0.1.1'); // rpcIdPlus increments from 0.1
+  });
+
+  it('should increment rpcId on multiple fetch calls', async () => {
+    // Test that rpcId increments properly on each fetch
+    const port = mockServer.address().port;
+    const targetUrl = `http://127.0.0.1:${port}/mock`;
+
+    const ctx = app.mockContext();
+    ctx.tracer = new app.Tracer('multi-trace-id', '0');
+    app.currentContext = ctx;
+
+    // First fetch
+    await app.fetch(targetUrl);
+    assert.strictEqual(receivedHeaders['x-trace-id'], 'multi-trace-id');
+    assert.strictEqual(receivedHeaders['x-rpc-id'], '0.1');
+
+    // Second fetch
+    await app.fetch(targetUrl);
+    assert.strictEqual(receivedHeaders['x-trace-id'], 'multi-trace-id');
+    assert.strictEqual(receivedHeaders['x-rpc-id'], '0.2');
+
+    // Third fetch
+    await app.fetch(targetUrl);
+    assert.strictEqual(receivedHeaders['x-trace-id'], 'multi-trace-id');
+    assert.strictEqual(receivedHeaders['x-rpc-id'], '0.3');
+  });
+});

From 602ef505383a61ab66d477b0657e18d5449d8659 Mon Sep 17 00:00:00 2001
From: Dipper30 <ddddipper30@gmail.com>
Date: Fri, 16 Jan 2026 16:54:04 +0800
Subject: [PATCH 2/9] chore: interceptor type

---
 index.d.ts | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/index.d.ts b/index.d.ts
index 8471bc054a..fe1f84ea82 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -295,6 +295,10 @@ declare module 'egg' {
     maxFreeSockets?: number;
   }
 
+  type Dispatcher = FetchFactory['getDispatcher'] extends () => infer R
+    ? R
+    : never;
+
   /** HttpClient config */
   export interface HttpClientConfig extends HttpClientBaseConfig {
     /** http.Agent */
@@ -319,8 +323,8 @@ declare module 'egg' {
     allowH2?: boolean;
     /** Custom lookup function for DNS resolution */
     lookup?: LookupFunction;
+    interceptors?: Dispatcher.DispatcherComposeInterceptor[];
   }
-
   export interface EggAppConfig {
     workerStartTimeout: number;
     baseDir: string;

From ce24bbb61db618d984f9908b16d3ada9850be038 Mon Sep 17 00:00:00 2001
From: Dipper30 <ddddipper30@gmail.com>
Date: Sat, 17 Jan 2026 16:42:33 +0800
Subject: [PATCH 3/9] chore: fix tsd

---
 index.d.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/index.d.ts b/index.d.ts
index fe1f84ea82..28ed159299 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -323,7 +323,7 @@ declare module 'egg' {
     allowH2?: boolean;
     /** Custom lookup function for DNS resolution */
     lookup?: LookupFunction;
-    interceptors?: Dispatcher.DispatcherComposeInterceptor[];
+    interceptors?: Parameters<Dispatcher['compose']>;
   }
   export interface EggAppConfig {
     workerStartTimeout: number;

From 53267db71c5c4a33caf55e7f50d563d3065a3ffc Mon Sep 17 00:00:00 2001
From: Dipper30 <ddddipper30@gmail.com>
Date: Sat, 17 Jan 2026 17:07:06 +0800
Subject: [PATCH 4/9] fix: test case

---
 test/fixtures/apps/fetch-tracer/app/router.js |  5 ++
 test/lib/core/fetch_tracer.test.js            | 49 ++++++++++---------
 2 files changed, 31 insertions(+), 23 deletions(-)

diff --git a/test/fixtures/apps/fetch-tracer/app/router.js b/test/fixtures/apps/fetch-tracer/app/router.js
index 7572256147..fee502681d 100644
--- a/test/fixtures/apps/fetch-tracer/app/router.js
+++ b/test/fixtures/apps/fetch-tracer/app/router.js
@@ -9,6 +9,11 @@ module.exports = app => {
     // Make a fetch request
     const response = await app.fetch(ctx.query.url);
 
+    const traceId = response.headers.get('x-trace-id');
+    if (traceId) ctx.set('x-trace-id', traceId);
+    const rpcId = response.headers.get('x-rpc-id');
+    if (rpcId) ctx.set('x-rpc-id', rpcId);
+
     ctx.body = {
       status: response.status,
       ok: response.ok,
diff --git a/test/lib/core/fetch_tracer.test.js b/test/lib/core/fetch_tracer.test.js
index 051851d167..45c3b2dc06 100644
--- a/test/lib/core/fetch_tracer.test.js
+++ b/test/lib/core/fetch_tracer.test.js
@@ -8,13 +8,21 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
 
   let app;
   let mockServer;
-  let receivedHeaders;
 
   before(async () => {
     // Create a mock server to capture headers
     mockServer = http.createServer((req, res) => {
-      receivedHeaders = req.headers;
-      res.writeHead(200, { 'Content-Type': 'application/json' });
+      const headers = {
+        'Content-Type': 'application/json',
+      };
+      if (req.headers['x-trace-id']) {
+        headers['x-trace-id'] = req.headers['x-trace-id'];
+      }
+      if (req.headers['x-rpc-id']) {
+        headers['x-rpc-id'] = req.headers['x-rpc-id'];
+      }
+
+      res.writeHead(200, headers);
       res.end(JSON.stringify({ ok: true }));
     });
 
@@ -32,10 +40,6 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
     }
   });
 
-  afterEach(() => {
-    receivedHeaders = null;
-  });
-
   it('should add tracer headers when fetch is called', async () => {
     const port = mockServer.address().port;
     const targetUrl = `http://127.0.0.1:${port}/mock`;
@@ -49,8 +53,8 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
     assert.strictEqual(response.body.ok, true);
 
     // Verify tracer headers were added with incremented rpcId
-    assert.strictEqual(receivedHeaders['x-trace-id'], 'test-trace-id-123');
-    assert.strictEqual(receivedHeaders['x-rpc-id'], '0.1'); // rpcIdPlus increments from 0
+    assert.strictEqual(response.headers['x-trace-id'], 'test-trace-id-123');
+    assert.strictEqual(response.headers['x-rpc-id'], '0.1'); // rpcIdPlus increments from 0
   });
 
   it('should work when tracer is not set', async () => {
@@ -65,8 +69,8 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
     assert.strictEqual(response.status, 200);
 
     // Verify no tracer headers when tracer is not set
-    assert.strictEqual(receivedHeaders['x-trace-id'], undefined);
-    assert.strictEqual(receivedHeaders['x-rpc-id'], undefined);
+    assert.strictEqual(response.headers.get('x-trace-id'), null);
+    assert.strictEqual(response.headers.get('x-rpc-id'), null);
   });
 
 
@@ -80,10 +84,9 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
     app.currentContext = ctx;
 
     const response = await app.fetch(targetUrl);
-
     assert.strictEqual(response.status, 200);
-    assert.strictEqual(receivedHeaders['x-trace-id'], 'early-trace-id');
-    assert.strictEqual(receivedHeaders['x-rpc-id'], '0.1.1'); // rpcIdPlus increments from 0.1
+    assert.strictEqual(response.headers.get('x-trace-id'), 'early-trace-id');
+    assert.strictEqual(response.headers.get('x-rpc-id'), '0.1.1'); // rpcIdPlus increments from 0.1
   });
 
   it('should increment rpcId on multiple fetch calls', async () => {
@@ -96,18 +99,18 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
     app.currentContext = ctx;
 
     // First fetch
-    await app.fetch(targetUrl);
-    assert.strictEqual(receivedHeaders['x-trace-id'], 'multi-trace-id');
-    assert.strictEqual(receivedHeaders['x-rpc-id'], '0.1');
+    let response = await app.fetch(targetUrl);
+    assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
+    assert.strictEqual(response.headers.get('x-rpc-id'), '0.1');
 
     // Second fetch
-    await app.fetch(targetUrl);
-    assert.strictEqual(receivedHeaders['x-trace-id'], 'multi-trace-id');
-    assert.strictEqual(receivedHeaders['x-rpc-id'], '0.2');
+    response = await app.fetch(targetUrl);
+    assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
+    assert.strictEqual(response.headers.get('x-rpc-id'), '0.2');
 
     // Third fetch
-    await app.fetch(targetUrl);
-    assert.strictEqual(receivedHeaders['x-trace-id'], 'multi-trace-id');
-    assert.strictEqual(receivedHeaders['x-rpc-id'], '0.3');
+    response = await app.fetch(targetUrl);
+    assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
+    assert.strictEqual(response.headers.get('x-rpc-id'), '0.3');
   });
 });

From eddb192496931b0e5707b10d6fea833a95fec032 Mon Sep 17 00:00:00 2001
From: Dipper30 <ddddipper30@gmail.com>
Date: Sat, 17 Jan 2026 19:55:19 +0800
Subject: [PATCH 5/9] fix: test case

---
 test/fixtures/apps/fetch-tracer/app.js | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/test/fixtures/apps/fetch-tracer/app.js b/test/fixtures/apps/fetch-tracer/app.js
index 96c37e06f8..b0f9c182e1 100644
--- a/test/fixtures/apps/fetch-tracer/app.js
+++ b/test/fixtures/apps/fetch-tracer/app.js
@@ -46,10 +46,32 @@ module.exports = class TracerApp {
           let traceId;
           let rpcId;
 
+          function setHeader(key, value) {
+            if (!opts.headers) {
+              opts.headers = {};
+            }
+            const headers = opts.headers;
+            if (typeof headers.set === 'function') {
+              headers.set(key, value);
+              return;
+            }
+            if (Array.isArray(headers)) {
+              if (headers.length > 0 && Array.isArray(headers[0])) {
+                headers.push([ key, value ]);
+              } else {
+                headers.push(key, value);
+              }
+              return;
+            }
+            headers[key] = value;
+          }
+
           try {
             if (tracer) {
-              traceId = opts.headers[HTTP_HEADER_TRACE_ID_KEY] = tracer.traceId;
-              rpcId = opts.headers[HTTP_HEADER_RPC_ID_KEY] = tracer.rpcIdPlus;
+              traceId = tracer.traceId;
+              setHeader(HTTP_HEADER_TRACE_ID_KEY, traceId);
+              rpcId = tracer.rpcIdPlus;
+              setHeader(HTTP_HEADER_RPC_ID_KEY, rpcId);
             }
           } catch (e) {
             e.message = '[egg-tracelog] set tracer header failed: ' + e.message;

From 693cd3714214fd39042413c81f9ec603662286b0 Mon Sep 17 00:00:00 2001
From: Dipper30 <ddddipper30@gmail.com>
Date: Sat, 17 Jan 2026 21:10:08 +0800
Subject: [PATCH 6/9] fix: test case fetch ctx

---
 test/fixtures/apps/fetch-tracer/app.js        |  7 ++-
 test/fixtures/apps/fetch-tracer/app/router.js | 26 +++++------
 test/lib/core/fetch_tracer.test.js            | 43 ++++++++++---------
 3 files changed, 41 insertions(+), 35 deletions(-)

diff --git a/test/fixtures/apps/fetch-tracer/app.js b/test/fixtures/apps/fetch-tracer/app.js
index b0f9c182e1..27c5d289b9 100644
--- a/test/fixtures/apps/fetch-tracer/app.js
+++ b/test/fixtures/apps/fetch-tracer/app.js
@@ -1,4 +1,5 @@
 const assert = require('assert');
+const { AsyncLocalStorage } = require('async_hooks');
 
 const TRACE_ID = Symbol('TRACE_ID');
 const RPC_ID = Symbol('RPC_ID');
@@ -26,6 +27,8 @@ module.exports = class TracerApp {
     assert(app.config);
     // Expose Tracer class for testing
     app.Tracer = Tracer;
+    // Use AsyncLocalStorage for proper context isolation
+    app.ctxStorage = new AsyncLocalStorage();
   }
 
   configWillLoad() {
@@ -42,7 +45,9 @@ module.exports = class TracerApp {
       dispatch => {
         const app = this.app;
         return async function tracerInterceptor(opts, handler) {
-          const tracer = app.currentContext?.tracer;
+          // Use AsyncLocalStorage to get context instead of global variable
+          const ctx = app.ctxStorage.getStore() || app.currentContext;
+          const tracer = ctx?.tracer;
           let traceId;
           let rpcId;
 
diff --git a/test/fixtures/apps/fetch-tracer/app/router.js b/test/fixtures/apps/fetch-tracer/app/router.js
index fee502681d..1df6792b0a 100644
--- a/test/fixtures/apps/fetch-tracer/app/router.js
+++ b/test/fixtures/apps/fetch-tracer/app/router.js
@@ -3,20 +3,20 @@ module.exports = app => {
     // Mock a tracer on the context using the Tracer class
     ctx.tracer = new app.Tracer('test-trace-id-123', '0');
 
-    // Store the current context so fetch can access it
-    app.currentContext = ctx;
+    // Use AsyncLocalStorage to store context for proper isolation
+    await app.ctxStorage.run(ctx, async () => {
+      // Make a fetch request
+      const response = await app.fetch(ctx.query.url);
 
-    // Make a fetch request
-    const response = await app.fetch(ctx.query.url);
+      const traceId = response.headers.get('x-trace-id');
+      if (traceId) ctx.set('x-trace-id', traceId);
+      const rpcId = response.headers.get('x-rpc-id');
+      if (rpcId) ctx.set('x-rpc-id', rpcId);
 
-    const traceId = response.headers.get('x-trace-id');
-    if (traceId) ctx.set('x-trace-id', traceId);
-    const rpcId = response.headers.get('x-rpc-id');
-    if (rpcId) ctx.set('x-rpc-id', rpcId);
-
-    ctx.body = {
-      status: response.status,
-      ok: response.ok,
-    };
+      ctx.body = {
+        status: response.status,
+        ok: response.ok,
+      };
+    });
   });
 };
diff --git a/test/lib/core/fetch_tracer.test.js b/test/lib/core/fetch_tracer.test.js
index 45c3b2dc06..0b83bd7299 100644
--- a/test/lib/core/fetch_tracer.test.js
+++ b/test/lib/core/fetch_tracer.test.js
@@ -58,12 +58,11 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
   });
 
   it('should work when tracer is not set', async () => {
-    // Clear currentContext
-    app.currentContext = null;
-
+    // Test without tracer context
     const port = mockServer.address().port;
     const targetUrl = `http://127.0.0.1:${port}/mock`;
 
+    // Call fetch without any context
     const response = await app.fetch(targetUrl);
 
     assert.strictEqual(response.status, 200);
@@ -81,9 +80,10 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
 
     const ctx = app.mockContext();
     ctx.tracer = new app.Tracer('early-trace-id', '0.1');
-    app.currentContext = ctx;
 
-    const response = await app.fetch(targetUrl);
+    const response = await app.ctxStorage.run(ctx, async () => {
+      return await app.fetch(targetUrl);
+    });
     assert.strictEqual(response.status, 200);
     assert.strictEqual(response.headers.get('x-trace-id'), 'early-trace-id');
     assert.strictEqual(response.headers.get('x-rpc-id'), '0.1.1'); // rpcIdPlus increments from 0.1
@@ -96,21 +96,22 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
 
     const ctx = app.mockContext();
     ctx.tracer = new app.Tracer('multi-trace-id', '0');
-    app.currentContext = ctx;
-
-    // First fetch
-    let response = await app.fetch(targetUrl);
-    assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
-    assert.strictEqual(response.headers.get('x-rpc-id'), '0.1');
-
-    // Second fetch
-    response = await app.fetch(targetUrl);
-    assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
-    assert.strictEqual(response.headers.get('x-rpc-id'), '0.2');
-
-    // Third fetch
-    response = await app.fetch(targetUrl);
-    assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
-    assert.strictEqual(response.headers.get('x-rpc-id'), '0.3');
+
+    await app.ctxStorage.run(ctx, async () => {
+      // First fetch
+      let response = await app.fetch(targetUrl);
+      assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
+      assert.strictEqual(response.headers.get('x-rpc-id'), '0.1');
+
+      // Second fetch
+      response = await app.fetch(targetUrl);
+      assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
+      assert.strictEqual(response.headers.get('x-rpc-id'), '0.2');
+
+      // Third fetch
+      response = await app.fetch(targetUrl);
+      assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
+      assert.strictEqual(response.headers.get('x-rpc-id'), '0.3');
+    });
   });
 });

From c2b1098a7d6878801f98dd3427c691f28a3f1624 Mon Sep 17 00:00:00 2001
From: Dipper30 <ddddipper30@gmail.com>
Date: Sun, 18 Jan 2026 02:28:23 +0800
Subject: [PATCH 7/9] Revert "fix: test case"

This reverts commit eddb192496931b0e5707b10d6fea833a95fec032.
---
 test/fixtures/apps/fetch-tracer/app.js | 26 ++------------------------
 1 file changed, 2 insertions(+), 24 deletions(-)

diff --git a/test/fixtures/apps/fetch-tracer/app.js b/test/fixtures/apps/fetch-tracer/app.js
index 27c5d289b9..e44e45eac2 100644
--- a/test/fixtures/apps/fetch-tracer/app.js
+++ b/test/fixtures/apps/fetch-tracer/app.js
@@ -51,32 +51,10 @@ module.exports = class TracerApp {
           let traceId;
           let rpcId;
 
-          function setHeader(key, value) {
-            if (!opts.headers) {
-              opts.headers = {};
-            }
-            const headers = opts.headers;
-            if (typeof headers.set === 'function') {
-              headers.set(key, value);
-              return;
-            }
-            if (Array.isArray(headers)) {
-              if (headers.length > 0 && Array.isArray(headers[0])) {
-                headers.push([ key, value ]);
-              } else {
-                headers.push(key, value);
-              }
-              return;
-            }
-            headers[key] = value;
-          }
-
           try {
             if (tracer) {
-              traceId = tracer.traceId;
-              setHeader(HTTP_HEADER_TRACE_ID_KEY, traceId);
-              rpcId = tracer.rpcIdPlus;
-              setHeader(HTTP_HEADER_RPC_ID_KEY, rpcId);
+              traceId = opts.headers[HTTP_HEADER_TRACE_ID_KEY] = tracer.traceId;
+              rpcId = opts.headers[HTTP_HEADER_RPC_ID_KEY] = tracer.rpcIdPlus;
             }
           } catch (e) {
             e.message = '[egg-tracelog] set tracer header failed: ' + e.message;

From d7bf2a2e71eb908fec6d34661a9010ee1039bfb9 Mon Sep 17 00:00:00 2001
From: Dipper30 <ddddipper30@gmail.com>
Date: Sun, 18 Jan 2026 02:29:26 +0800
Subject: [PATCH 8/9] Revert "fix: test case fetch ctx"

This reverts commit 693cd3714214fd39042413c81f9ec603662286b0.
---
 test/fixtures/apps/fetch-tracer/app.js        |  7 +--
 test/fixtures/apps/fetch-tracer/app/router.js | 26 +++++------
 test/lib/core/fetch_tracer.test.js            | 43 +++++++++----------
 3 files changed, 35 insertions(+), 41 deletions(-)

diff --git a/test/fixtures/apps/fetch-tracer/app.js b/test/fixtures/apps/fetch-tracer/app.js
index e44e45eac2..96c37e06f8 100644
--- a/test/fixtures/apps/fetch-tracer/app.js
+++ b/test/fixtures/apps/fetch-tracer/app.js
@@ -1,5 +1,4 @@
 const assert = require('assert');
-const { AsyncLocalStorage } = require('async_hooks');
 
 const TRACE_ID = Symbol('TRACE_ID');
 const RPC_ID = Symbol('RPC_ID');
@@ -27,8 +26,6 @@ module.exports = class TracerApp {
     assert(app.config);
     // Expose Tracer class for testing
     app.Tracer = Tracer;
-    // Use AsyncLocalStorage for proper context isolation
-    app.ctxStorage = new AsyncLocalStorage();
   }
 
   configWillLoad() {
@@ -45,9 +42,7 @@ module.exports = class TracerApp {
       dispatch => {
         const app = this.app;
         return async function tracerInterceptor(opts, handler) {
-          // Use AsyncLocalStorage to get context instead of global variable
-          const ctx = app.ctxStorage.getStore() || app.currentContext;
-          const tracer = ctx?.tracer;
+          const tracer = app.currentContext?.tracer;
           let traceId;
           let rpcId;
 
diff --git a/test/fixtures/apps/fetch-tracer/app/router.js b/test/fixtures/apps/fetch-tracer/app/router.js
index 1df6792b0a..fee502681d 100644
--- a/test/fixtures/apps/fetch-tracer/app/router.js
+++ b/test/fixtures/apps/fetch-tracer/app/router.js
@@ -3,20 +3,20 @@ module.exports = app => {
     // Mock a tracer on the context using the Tracer class
     ctx.tracer = new app.Tracer('test-trace-id-123', '0');
 
-    // Use AsyncLocalStorage to store context for proper isolation
-    await app.ctxStorage.run(ctx, async () => {
-      // Make a fetch request
-      const response = await app.fetch(ctx.query.url);
+    // Store the current context so fetch can access it
+    app.currentContext = ctx;
 
-      const traceId = response.headers.get('x-trace-id');
-      if (traceId) ctx.set('x-trace-id', traceId);
-      const rpcId = response.headers.get('x-rpc-id');
-      if (rpcId) ctx.set('x-rpc-id', rpcId);
+    // Make a fetch request
+    const response = await app.fetch(ctx.query.url);
 
-      ctx.body = {
-        status: response.status,
-        ok: response.ok,
-      };
-    });
+    const traceId = response.headers.get('x-trace-id');
+    if (traceId) ctx.set('x-trace-id', traceId);
+    const rpcId = response.headers.get('x-rpc-id');
+    if (rpcId) ctx.set('x-rpc-id', rpcId);
+
+    ctx.body = {
+      status: response.status,
+      ok: response.ok,
+    };
   });
 };
diff --git a/test/lib/core/fetch_tracer.test.js b/test/lib/core/fetch_tracer.test.js
index 0b83bd7299..45c3b2dc06 100644
--- a/test/lib/core/fetch_tracer.test.js
+++ b/test/lib/core/fetch_tracer.test.js
@@ -58,11 +58,12 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
   });
 
   it('should work when tracer is not set', async () => {
-    // Test without tracer context
+    // Clear currentContext
+    app.currentContext = null;
+
     const port = mockServer.address().port;
     const targetUrl = `http://127.0.0.1:${port}/mock`;
 
-    // Call fetch without any context
     const response = await app.fetch(targetUrl);
 
     assert.strictEqual(response.status, 200);
@@ -80,10 +81,9 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
 
     const ctx = app.mockContext();
     ctx.tracer = new app.Tracer('early-trace-id', '0.1');
+    app.currentContext = ctx;
 
-    const response = await app.ctxStorage.run(ctx, async () => {
-      return await app.fetch(targetUrl);
-    });
+    const response = await app.fetch(targetUrl);
     assert.strictEqual(response.status, 200);
     assert.strictEqual(response.headers.get('x-trace-id'), 'early-trace-id');
     assert.strictEqual(response.headers.get('x-rpc-id'), '0.1.1'); // rpcIdPlus increments from 0.1
@@ -96,22 +96,21 @@ describe('test/lib/core/fetch_tracer.test.js', () => {
 
     const ctx = app.mockContext();
     ctx.tracer = new app.Tracer('multi-trace-id', '0');
-
-    await app.ctxStorage.run(ctx, async () => {
-      // First fetch
-      let response = await app.fetch(targetUrl);
-      assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
-      assert.strictEqual(response.headers.get('x-rpc-id'), '0.1');
-
-      // Second fetch
-      response = await app.fetch(targetUrl);
-      assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
-      assert.strictEqual(response.headers.get('x-rpc-id'), '0.2');
-
-      // Third fetch
-      response = await app.fetch(targetUrl);
-      assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
-      assert.strictEqual(response.headers.get('x-rpc-id'), '0.3');
-    });
+    app.currentContext = ctx;
+
+    // First fetch
+    let response = await app.fetch(targetUrl);
+    assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
+    assert.strictEqual(response.headers.get('x-rpc-id'), '0.1');
+
+    // Second fetch
+    response = await app.fetch(targetUrl);
+    assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
+    assert.strictEqual(response.headers.get('x-rpc-id'), '0.2');
+
+    // Third fetch
+    response = await app.fetch(targetUrl);
+    assert.strictEqual(response.headers.get('x-trace-id'), 'multi-trace-id');
+    assert.strictEqual(response.headers.get('x-rpc-id'), '0.3');
   });
 });

From dad5dbeed7b8fc6ed2ca339c4532123d94410317 Mon Sep 17 00:00:00 2001
From: Dipper30 <ddddipper30@gmail.com>
Date: Sun, 18 Jan 2026 02:30:26 +0800
Subject: [PATCH 9/9] fix: fetch initialization

---
 lib/core/fetch_factory.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/lib/core/fetch_factory.js b/lib/core/fetch_factory.js
index 9225118a57..cfc3bed858 100644
--- a/lib/core/fetch_factory.js
+++ b/lib/core/fetch_factory.js
@@ -3,7 +3,8 @@ const debug = require('util').debuglog('egg:lib:core:fetch_factory');
 const mainNodejsVersion = parseInt(process.versions.node.split('.')[0]);
 let FetchFactory;
 let fetch;
-let fetchInitialized = false;
+// Track initialization per app instance by storing a WeakMap
+const fetchInitializedMap = new WeakMap();
 let safeFetch;
 let ssrfFetchFactory;
 
@@ -15,7 +16,7 @@ if (mainNodejsVersion >= 20) {
     debug('urllib4 enable');
 
     fetch = function(url, init) {
-      if (!fetchInitialized) {
+      if (!fetchInitializedMap.get(this)) {
         const clientOptions = {};
         if (this.config.httpclient?.lookup) {
           clientOptions.lookup = this.config.httpclient.lookup;
@@ -31,7 +32,7 @@ if (mainNodejsVersion >= 20) {
           FetchFactory.setDispatcher(originalDispatcher.compose(interceptors));
         }
 
-        fetchInitialized = true;
+        fetchInitializedMap.set(this, true);
       }
       return FetchFactory.fetch(url, init);
     };