Add idp arg, include namespace in uri and encode query params.

lua/auth.lua

@@ -3,5 +3,9 @@ if not returnTo then
    returnTo = ngx.var.scheme .. '://' .. ngx.var.host .. '/'
 end
 local authServer = os.getenv('auth_server')
+local idp = os.getenv('idp')
+local namespace = os.getenv('namespace')
 local action = ngx.var.action
-ngx.redirect('https://' .. authServer .. '/sp/' .. action .. '/?ReturnTo=' .. returnTo)
+
+local params = ngx.encode_args({'ReturnTo' = returnTo, 'Idp' = idp})
+ngx.redirect('https://' .. authServer .. '/' .. namespace .. '/' .. action .. '?' .. params)

nginx/nginx.conf

@@ -7,6 +7,7 @@ env memcache;
 env feide_mode;
 env auth_server;
 env upstream_port;
+env idp;
 
 events {
 	worker_connections 768;