fix: authz_keycloak plugin giving 500 error (#10763)

apisix/plugins/authz-keycloak.lua

@@ -503,7 +503,7 @@ local function authz_keycloak_resolve_resource(conf, uri, sa_access_token)
     if not resource_registration_endpoint then
         local err = "Unable to determine registration endpoint."
         log.error(err)
-        return 503, err
+        return nil, err
     end
 
     log.debug("Resource registration endpoint: ", resource_registration_endpoint)

t/plugin/authz-keycloak2.t

@@ -654,3 +654,90 @@ true
 GET /t
 --- response_body
 true
+
+
+
+=== TEST 16: add plugin with lazy_load_paths when resource_registration_endpoint is neither in config nor in the discovery doc
+--- config
+    location /t {
+        content_by_lua_block {
+            local t = require("lib.test_admin").test
+            local code, body = t('/apisix/admin/routes/1',
+                 ngx.HTTP_PUT,
+                 [[{
+                        "plugins": {
+                            "authz-keycloak": {
+                                "discovery": "http://127.0.0.1:8080/realms/University/.well-known/openid-configuration",
+                                "client_id": "course_management",
+                                "client_secret": "d1ec69e9-55d2-4109-a3ea-befa071579d5",
+                                "lazy_load_paths": true
+                            }
+                        },
+                        "upstream": {
+                            "nodes": {
+                                "127.0.0.1:1982": 1
+                            },
+                            "type": "roundrobin"
+                        },
+                        "uri": "/course/foo"
+                }]]
+                )
+
+            if code >= 300 then
+                ngx.status = code
+            end
+            ngx.say(body)
+        }
+    }
+--- request
+GET /t
+--- response_body
+passed
+
+
+
+=== TEST 17: Get access token for student and access view course route.
+--- config
+    location /t {
+        content_by_lua_block {
+            local json_decode = require("toolkit.json").decode
+            local http = require "resty.http"
+            local httpc = http.new()
+            local uri = "http://127.0.0.1:8080/realms/University/protocol/openid-connect/token"
+            local res, err = httpc:request_uri(uri, {
+                    method = "POST",
+                    body = "grant_type=password&client_id=course_management&client_secret=d1ec69e9-55d2-4109-a3ea-befa071579d5&username=student@gmail.com&password=123456",
+                    headers = {
+                        ["Content-Type"] = "application/x-www-form-urlencoded"
+                    }
+                })
+
+            if res.status == 200 then
+                local body = json_decode(res.body)
+                local accessToken = body["access_token"]
+
+
+                uri = "http://127.0.0.1:" .. ngx.var.server_port .. "/course/foo"
+                local res, err = httpc:request_uri(uri, {
+                    method = "GET",
+                    headers = {
+                        ["Authorization"] = "Bearer " .. accessToken,
+                    }
+                 })
+
+                if res.status == 503 then
+                    ngx.say(true)
+                else
+                    ngx.say(false)
+                end
+            else
+                ngx.say(false)
+            end
+        }
+    }
+--- request
+GET /t
+--- response_body
+true
+--- error_log
+Unable to determine registration endpoint.