Update app.py

app.py

@@ -22,6 +22,10 @@ app.add_middleware(
     allow_headers=['*'],
 )
 
+
+# Define retriever_chain as a global variable
+retriever_chain = None
+
 # Function to crawl all URLs from a domain
 def get_all_links_from_domain(domain_url):
     print("domain url " + domain_url)