Dealing with cache expiration

gemini/gemini.py

@@ -106,7 +106,7 @@ def main():
                     json.dump(context_data, f, indent=4)
 
         # ---------------------------------------------------------
-        # CACHE CREATION LOGIC
+        # CACHE VALIDATION & CREATION LOGIC
         # ---------------------------------------------------------
         system_instruction = (
             "You are a hybrid data extraction tool. If a specific format or file format output is requested "
@@ -128,6 +128,8 @@ def main():
             
             if model_cache_info:
                 cached_files_set = set(model_cache_info.get("cached_file_ids", []))
+                
+                # Check 1: Have the files changed?
                 if current_files_set != cached_files_set:
                     print(f"File list changed. Destroying stale {args.model} cache to rebuild...")
                     try:
@@ -135,6 +137,20 @@ def main():
                     except Exception as e:
                         print(f"Warning: Could not delete stale cache. {e}", file=sys.stderr)
                     rebuild_cache = True
+                else:
+                    # Check 2: Does the cache still exist on the server?
+                    print(f"Verifying existing cache for {args.model}: {model_cache_info['cache_id']}...")
+                    try:
+                        client.caches.get(name=model_cache_info['cache_id'])
+                        print("Cache verified. Extending TTL by 60 minutes...")
+                        client.caches.update(
+                            name=model_cache_info['cache_id'],
+                            config=types.UpdateCachedContentConfig(ttl="3600s")
+                        )
+                        active_cache_id = model_cache_info['cache_id']
+                    except Exception as e:
+                        print(f"Cache expired or not found. Flagging for rebuild. ({e})")
+                        rebuild_cache = True
             else:
                 rebuild_cache = True
 
@@ -167,18 +183,6 @@ def main():
                         cache_too_small = True
                     else:
                         raise e
-                
-            elif not cache_too_small and model_cache_info:
-                active_cache_id = model_cache_info["cache_id"]
-                print(f"Loading existing cache for {args.model}: {active_cache_id}")
-                print("Extending cache TTL by 60 minutes...")
-                try:
-                    client.caches.update(
-                        name=active_cache_id,
-                        config=types.UpdateCachedContentConfig(ttl="3600s")
-                    )
-                except Exception as e:
-                     print(f"Warning: Failed to update cache TTL. {e}")
 
         # ---------------------------------------------------------
         # GENERATION LOGIC (WITH HISTORY)