fix: socks5 proxy rejected connection - failure

src/lambda/tailscale-proxy/index.ts

@@ -7,7 +7,7 @@ import {
 import { SocksProxyAgent } from 'socks-proxy-agent';
 
 async function proxyHttpRequest(
-  target: Pick<http.RequestOptions, 'hostname' | 'port' | 'agent'>,
+  target: Pick<http.RequestOptions, 'hostname' | 'port'>,
   isHttps: boolean | undefined,
   request: {
     path: string;
@@ -16,53 +16,83 @@ async function proxyHttpRequest(
     body: string | undefined;
   },
 ): Promise<APIGatewayProxyResultV2> {
-  return new Promise((resolve, reject) => {
-    const chunks: Buffer[] = [];
-    const httpLib = isHttps == undefined ?
-      (target.port == 443 ? https : http) :
-      (isHttps ? https : http);
-    const apiRequest = httpLib.request({
-      ...target,
-      path: request.path,
-      method: request.method,
-      headers: request.headers,
-    }, (res: http.IncomingMessage) => {
-      res.on('data', (chunk: Buffer) => {
-        chunks.push(chunk);
-      });
-      res.on('end', () => {
-        const responseBody = Buffer.concat(chunks);
-        resolve({
-          statusCode: res.statusCode || 500,
-          headers: res.headers as Record<string, string>,
-          body: responseBody.toString('base64'),
-          isBase64Encoded: true,
+
+  async function requestPromise(): Promise<APIGatewayProxyResultV2> {
+    const socksProxyAgent = new SocksProxyAgent('socks://localhost:1055');
+    return new Promise((resolve, reject) => {
+      const chunks: Buffer[] = [];
+      const httpLib = isHttps == undefined ?
+        (target.port == 443 ? https : http) :
+        (isHttps ? https : http);
+      const apiRequest = httpLib.request({
+        ...target,
+        agent: socksProxyAgent,
+        path: request.path,
+        method: request.method,
+        headers: request.headers,
+      }, (res: http.IncomingMessage) => {
+        res.on('data', (chunk: Buffer) => {
+          chunks.push(chunk);
+        });
+        res.on('end', () => {
+          const responseBody = Buffer.concat(chunks);
+          resolve({
+            statusCode: res.statusCode || 500,
+            headers: res.headers as Record<string, string>,
+            body: responseBody.toString('base64'),
+            isBase64Encoded: true,
+          });
+        });
+        res.on('error', (error: Error): void => {
+          console.error('Error receiving response:', error);
+          reject(error);
         });
       });
-      res.on('error', (error: Error): void => {
-        console.error('Error receiving response:', error);
+
+      apiRequest.on('error', (error: Error): void => {
+        console.error('Error sending request:', error);
         reject(error);
       });
-    });
 
-    apiRequest.on('error', (error: Error): void => {
-      console.error('Error sending request:', error);
-      reject(error);
+      if (request.body != null) {
+        apiRequest.write(request.body);
+      }
+      apiRequest.end();
     });
+  }
+
 
-    if (request.body != null) {
-      apiRequest.write(request.body);
+  const connectionRetryDelays = [10, 50, 100, 500, 1000, 2000, 3000];
+  let attempt = 0;
+  let success = false;
+  let response: APIGatewayProxyResultV2;
+
+  do {
+    try {
+      response = await requestPromise();
+      success = true;
+    } catch (error) {
+      if (error == 'Error: Socks5 proxy rejected connection - Failure' && attempt < connectionRetryDelays.length) {
+        console.error('Error: Socks5 proxy rejected connection - Failure');
+        console.log('Retrying in', connectionRetryDelays[attempt], 'ms');
+        await new Promise((resolve) => setTimeout(resolve, connectionRetryDelays[attempt]));
+        attempt++;
+      } else {
+        throw error;
+      }
     }
-    apiRequest.end();
-  });
+  } while (!success && attempt < connectionRetryDelays.length);
+
+  if (attempt > 0) {
+    console.log('Error: Socks5 proxy rejected connection - Failure - RESOLVED - attempt:', attempt, 'total delay time:', connectionRetryDelays.slice(0, attempt).reduce((a, b) => a + b, 0));
+  }
+
+  return response!;
 }
 
 export async function handler(event: APIGatewayProxyEventV2): Promise<APIGatewayProxyResultV2> {
-
   let metrics: Metrics | undefined;
   try {
-    const socksProxyAgent = new SocksProxyAgent('socks://localhost:1055');
-
     let isHttps = undefined; // Auto-detect, will be set for port 443
     if (!event.headers['ts-target-ip']) {
       return {
@@ -102,15 +132,13 @@ export async function handler(event: APIGatewayProxyEventV2): Promise<APIGateway
     const response = await proxyHttpRequest({
       hostname: event.headers['ts-target-ip'],
       port: event.headers['ts-target-port'],
-      agent: socksProxyAgent,
     }, isHttps,
     {
       path: event.requestContext.http.path,
       headers: targetHeaders,
       method: event.requestContext.http.method,
       body: event.body,
-    },
-    );
+    });
 
     metrics?.addMetric('success', MetricUnit.Count, 1);
     return response;