Enhance proxy agent initialization and teardown logic to prevent concurrent calls and improve resource management

Author: tsvi

packages/main/src/backend/proxyConfig/agentManager.ts

@@ -11,61 +11,111 @@ interface ProxyState {
   originalHttpAgent: HttpAgent;
   originalHttpsAgent: HttpsAgent;
   proxyAgent: ProxyAgent;
+  originalHttpProxy: string | undefined;
+  originalHttpsProxy: string | undefined;
 }
 
 let proxyState: ProxyState | null = null;
+let isInitializing = false;
+let isTearingDown = false;
 
 export function initializeProxyAgents(proxyUrl: string): void {
-  if (proxyState?.proxyUrl === proxyUrl) {
-    logger.log(`Proxy already initialized with ${proxyUrl}`);
+  if (isInitializing) {
+    logger.log('Proxy initialization already in progress, ignoring concurrent call');
     return;
   }
 
-  logger.log(`Initializing proxy agents with ${proxyUrl}`);
-
-  // Set environment variables for @puppeteer/browsers
-  process.env.HTTP_PROXY = proxyUrl;
-  process.env.HTTPS_PROXY = proxyUrl;
-
-  // Store original agents and create proxy agent
-  const proxyAgent = new ProxyAgent({ getProxyForUrl: () => proxyUrl });
-
-  proxyState = {
-    proxyUrl,
-    originalHttpAgent: http.globalAgent,
-    originalHttpsAgent: https.globalAgent,
-    proxyAgent,
-  };
+  if (isTearingDown) {
+    throw new Error('Cannot initialize proxy while teardown is in progress');
+  }
 
-  // Set proxy agents globally
-  http.globalAgent = proxyAgent;
-  https.globalAgent = proxyAgent;
+  if (proxyState?.proxyUrl === proxyUrl) {
+    logger.log(`Proxy already initialized with ${proxyUrl}`);
+    return;
+  }
 
-  // Configure undici for fetch() API
-  const undiciProxyAgent = new UndiciProxyAgent(proxyUrl);
-  setGlobalDispatcher(undiciProxyAgent);
+  isInitializing = true;
+
+  try {
+    // Clean up previous proxy before setting up a new one to avoid resource leaks
+    if (proxyState) {
+      tearDownProxyAgents();
+    }
+
+    logger.log(`Initializing proxy agents with ${proxyUrl}`);
+
+    // Store original environment variables so they can be restored later
+    const originalHttpProxy = process.env.HTTP_PROXY;
+    const originalHttpsProxy = process.env.HTTPS_PROXY;
+
+    // Set environment variables for @puppeteer/browsers
+    process.env.HTTP_PROXY = proxyUrl;
+    process.env.HTTPS_PROXY = proxyUrl;
+
+    // Store original agents and create proxy agent
+    const proxyAgent = new ProxyAgent({ getProxyForUrl: () => proxyUrl });
+
+    proxyState = {
+      proxyUrl,
+      originalHttpAgent: http.globalAgent,
+      originalHttpsAgent: https.globalAgent,
+      proxyAgent,
+      originalHttpProxy,
+      originalHttpsProxy,
+    };
+
+    // Set proxy agents globally
+    http.globalAgent = proxyAgent;
+    https.globalAgent = proxyAgent;
+
+    // Configure undici for fetch() API
+    const undiciProxyAgent = new UndiciProxyAgent(proxyUrl);
+    setGlobalDispatcher(undiciProxyAgent);
+  } finally {
+    isInitializing = false;
+  }
 }
 
 export function tearDownProxyAgents(): void {
+  if (isTearingDown) {
+    logger.log('Proxy teardown already in progress, ignoring concurrent call');
+    return;
+  }
+
   if (!proxyState) {
     return;
   }
 
-  logger.log('Tearing down proxy agents');
+  isTearingDown = true;
+
+  try {
+    logger.log('Tearing down proxy agents');
 
-  // Restore original agents
-  http.globalAgent = proxyState.originalHttpAgent;
-  https.globalAgent = proxyState.originalHttpsAgent;
+    // Restore original agents
+    http.globalAgent = proxyState.originalHttpAgent;
+    https.globalAgent = proxyState.originalHttpsAgent;
 
-  // Clear environment variables
-  delete process.env.HTTP_PROXY;
-  delete process.env.HTTPS_PROXY;
+    // Restore original environment variables instead of deleting them
+    if (proxyState.originalHttpProxy !== undefined) {
+      process.env.HTTP_PROXY = proxyState.originalHttpProxy;
+    } else {
+      delete process.env.HTTP_PROXY;
+    }
 
-  // Reset undici dispatcher to default
-  setGlobalDispatcher(new UndiciAgent());
+    if (proxyState.originalHttpsProxy !== undefined) {
+      process.env.HTTPS_PROXY = proxyState.originalHttpsProxy;
+    } else {
+      delete process.env.HTTPS_PROXY;
+    }
 
-  // Clear state
-  proxyState = null;
+    // Reset undici dispatcher to default
+    setGlobalDispatcher(new UndiciAgent());
+
+    // Clear state
+    proxyState = null;
+  } finally {
+    isTearingDown = false;
+  }
 }
 
 export function getCurrentProxyUrl(): string | null {