fallback changes from PR #35

src/cloudcode/message-handler.js

@@ -18,6 +18,7 @@ import { logger } from '../utils/logger.js';
 import { parseResetTime } from './rate-limit-parser.js';
 import { buildCloudCodeRequest, buildHeaders } from './request-builder.js';
 import { parseThinkingSSEResponse } from './sse-parser.js';
+import { getFallbackModel } from '../fallback-config.js';
 
 /**
  * Send a non-streaming request to Cloud Code with multi-account support
@@ -32,7 +33,7 @@ import { parseThinkingSSEResponse } from './sse-parser.js';
  * @returns {Promise<Object>} Anthropic-format response object
  * @throws {Error} If max retries exceeded or no accounts available
  */
-export async function sendMessage(anthropicRequest, accountManager) {
+export async function sendMessage(anthropicRequest, accountManager, fallbackEnabled = false) {
     const model = anthropicRequest.model;
     const isThinking = isThinkingModel(model);
 
@@ -76,6 +77,16 @@ export async function sendMessage(anthropicRequest, accountManager) {
             }
 
             if (!account) {
+                // Check if fallback is enabled and available
+                if (fallbackEnabled) {
+                    const fallbackModel = getFallbackModel(model);
+                    if (fallbackModel) {
+                        logger.warn(`[CloudCode] All accounts exhausted for ${model}. Attempting fallback to ${fallbackModel}`);
+                        // Retry with fallback model
+                        const fallbackRequest = { ...anthropicRequest, model: fallbackModel };
+                        return await sendMessage(fallbackRequest, accountManager, false); // Disable fallback for recursive call
+                    }
+                }
                 throw new Error('No accounts available');
             }
         }

src/cloudcode/streaming-handler.js

@@ -16,6 +16,7 @@ import { logger } from '../utils/logger.js';
 import { parseResetTime } from './rate-limit-parser.js';
 import { buildCloudCodeRequest, buildHeaders } from './request-builder.js';
 import { streamSSEResponse } from './sse-streamer.js';
+import { getFallbackModel } from '../fallback-config.js';
 
 
 /**
@@ -31,7 +32,7 @@ import { streamSSEResponse } from './sse-streamer.js';
  * @yields {Object} Anthropic-format SSE events (message_start, content_block_start, content_block_delta, etc.)
  * @throws {Error} If max retries exceeded or no accounts available
  */
-export async function* sendMessageStream(anthropicRequest, accountManager) {
+export async function* sendMessageStream(anthropicRequest, accountManager, fallbackEnabled = false) {
     const model = anthropicRequest.model;
 
     // Retry loop with account failover
@@ -74,6 +75,17 @@ export async function* sendMessageStream(anthropicRequest, accountManager) {
             }
 
             if (!account) {
+                // Check if fallback is enabled and available
+                if (fallbackEnabled) {
+                    const fallbackModel = getFallbackModel(model);
+                    if (fallbackModel) {
+                        logger.warn(`[CloudCode] All accounts exhausted for ${model}. Attempting fallback to ${fallbackModel} (streaming)`);
+                        // Retry with fallback model
+                        const fallbackRequest = { ...anthropicRequest, model: fallbackModel };
+                        yield* sendMessageStream(fallbackRequest, accountManager, false); // Disable fallback for recursive call
+                        return;
+                    }
+                }
                 throw new Error('No accounts available');
             }
         }

src/fallback-config.js

@@ -0,0 +1,36 @@
+/**
+ * Model Fallback Configuration
+ * 
+ * Defines fallback mappings for when a model's quota is exhausted across all accounts.
+ * Enables graceful degradation to alternative models with similar capabilities.
+ */
+
+/**
+ * Model fallback mapping
+ * Maps primary model ID to fallback model ID
+ */
+export const MODEL_FALLBACK_MAP = {
+    'gemini-3-pro-high': 'claude-sonnet-4-5-thinking',
+    'gemini-3-pro-low': 'claude-sonnet-4-5',
+    'claude-opus-4-5-thinking': 'gemini-3-pro-high',
+    'claude-sonnet-4-5-thinking': 'gemini-3-pro-high',
+    'claude-sonnet-4-5': 'gemini-3-pro-low'
+};
+
+/**
+ * Get fallback model for a given model ID
+ * @param {string} model - Primary model ID
+ * @returns {string|null} Fallback model ID or null if no fallback exists
+ */
+export function getFallbackModel(model) {
+    return MODEL_FALLBACK_MAP[model] || null;
+}
+
+/**
+ * Check if a model has a fallback configured
+ * @param {string} model - Model ID to check
+ * @returns {boolean} True if fallback exists
+ */
+export function hasFallback(model) {
+    return model in MODEL_FALLBACK_MAP;
+}

src/index.js

@@ -12,6 +12,7 @@ import os from 'os';
 // Parse command line arguments
 const args = process.argv.slice(2);
 const isDebug = args.includes('--debug') || process.env.DEBUG === 'true';
+const isFallbackEnabled = args.includes('--fallback') || process.env.FALLBACK === 'true';
 
 // Initialize logger
 logger.setDebug(isDebug);
@@ -20,6 +21,13 @@ if (isDebug) {
     logger.debug('Debug mode enabled');
 }
 
+if (isFallbackEnabled) {
+    logger.info('Model fallback mode enabled');
+}
+
+// Export fallback flag for server to use
+export const FALLBACK_ENABLED = isFallbackEnabled;
+
 const PORT = process.env.PORT || DEFAULT_PORT;
 
 // Home directory for account storage
@@ -40,14 +48,22 @@ app.listen(PORT, () => {
     if (!isDebug) {
         controlSection += '║    --debug            Enable debug logging                   ║\n';
     }
+    if (!isFallbackEnabled) {
+        controlSection += '║    --fallback         Enable model fallback on quota exhaust ║\n';
+    }
     controlSection += '║    Ctrl+C             Stop server                            ║';
 
-    // Build status section if debug mode is active
+    // Build status section if any modes are active
     let statusSection = '';
-    if (isDebug) {
+    if (isDebug || isFallbackEnabled) {
         statusSection = '║                                                              ║\n';
         statusSection += '║  Active Modes:                                               ║\n';
-        statusSection += '║    ✓ Debug mode enabled                                      ║\n';
+        if (isDebug) {
+            statusSection += '║    ✓ Debug mode enabled                                      ║\n';
+        }
+        if (isFallbackEnabled) {
+            statusSection += '║    ✓ Model fallback enabled                                  ║\n';
+        }
     }
 
     logger.log(`

src/server.js

@@ -13,6 +13,10 @@ import { AccountManager } from './account-manager/index.js';
 import { formatDuration } from './utils/helpers.js';
 import { logger } from './utils/logger.js';
 
+// Parse fallback flag directly from command line args to avoid circular dependency
+const args = process.argv.slice(2);
+const FALLBACK_ENABLED = args.includes('--fallback') || process.env.FALLBACK === 'true';
+
 const app = express();
 
 // Initialize account manager (will be fully initialized on first request or startup)
@@ -595,7 +599,7 @@ app.post('/v1/messages', async (req, res) => {
 
             try {
                 // Use the streaming generator with account manager
-                for await (const event of sendMessageStream(request, accountManager)) {
+                for await (const event of sendMessageStream(request, accountManager, FALLBACK_ENABLED)) {
                     res.write(`event: ${event.type}\ndata: ${JSON.stringify(event)}\n\n`);
                     // Flush after each event for real-time streaming
                     if (res.flush) res.flush();
@@ -616,7 +620,7 @@ app.post('/v1/messages', async (req, res) => {
 
         } else {
             // Handle non-streaming response
-            const response = await sendMessage(request, accountManager);
+            const response = await sendMessage(request, accountManager, FALLBACK_ENABLED);
             res.json(response);
         }