add

@@ -36,5 +36,10 @@ function M:init()
 
  
 function M:get_percentage()
-  return lua_context.lua_conf_cache:get("switch:percentage")
+  local per =  lua_context.lua_conf_cache:get("switch:percentage")
+  if not per then
+    return 0
+  else
+   return tonumber(per)
+  end
 end

@@ -2,15 +2,16 @@ local http_request = require "http_request"
 local switch_controller = require "switch_controller"
 
  
-function do_direct(redirect_path)
+function do_direct(redirectPath)
         local request_method = ngx.var.request_method;
         if "GET" == request_method then
-                ngx.exec(redirect_path,ngx.req.get_uri_args());
+                return ngx.exec(redirectPath,ngx.req.get_uri_args());
         else
-                ngx.exec(redirect_path);
+                return ngx.exec(redirectPath);
         end
 end
 
+
 function route(redirectPath)
 
         --- modify content-type, add utf-8 charset if absent---
@@ -19,7 +20,7 @@ function route(redirectPath)
         end
 
         --- if url match the service url, just redirect path with uri
-        if  ngx.var.service_matched == "1"  then 
+        if  ngx.var.service_matched and ngx.var.service_matched == "1"  then 
                 local uri = ngx.var.uri 
                 if nil == ngx.req.get_uri_args() then
                   return ngx.exec(redirectPath ..uri);
@@ -74,9 +75,9 @@ function main()
    local  redirectPath = "/apigateway" ;
 
    init_read_body()
-   
+
    local percentage = switch_controller.get_percentage()
-   if percentage and percentage >= 1 then
+   if percentage >= 1 then
         local uid = http_request.get_req_param("uid")
         if not uid then
             uid = 0
@@ -93,4 +94,18 @@ function main()
 end
 
 ---- run ----- 
-main()
\ No newline at end of file
+status , errMsg = pcall(main)
+if not status then
+   ngx.log(ngx.ERR, "call method [main] failed.", errMsg)
+   --- default
+   if  ngx.var.service_matched and ngx.var.service_matched == "1"  then 
+       local uri = ngx.var.uri 
+       if nil == ngx.req.get_uri_args() then
+            return ngx.exec(redirectPath ..uri);
+           else
+            return ngx.exec(redirectPath ..uri, ngx.req.get_uri_args());
+        end
+  else
+    do_direct("/apigateway")
+  end
+end