feat: allow customizing response in the plugin (apache#7128)

Signed-off-by: spacewander <spacewanderlzx@gmail.com>

apisix/plugin.lua

@@ -142,6 +142,16 @@ local function load_plugin(name, plugins_list, plugin_type)
         end
 
         properties.disable = plugin_injected_schema.disable
+
+        if properties._meta then
+            core.log.error("invalid plugin [", name,
+                           "]: found forbidden '_meta' field in the schema")
+            return
+        end
+
+        properties._meta = plugin_injected_schema._meta
+        -- new injected fields should be added under `_meta`
+
         plugin.schema['$comment'] = plugin_injected_schema['$comment']
     end
 
@@ -743,11 +753,19 @@ function _M.run_plugin(phase, plugins, api_ctx)
             local phase_func = plugins[i][phase]
             if phase_func then
                 plugin_run = true
-                local code, body = phase_func(plugins[i + 1], api_ctx)
+                local conf = plugins[i + 1]
+                local code, body = phase_func(conf, api_ctx)
                 if code or body then
                     if is_http then
                         if code >= 400 then
                             core.log.warn(plugins[i].name, " exits with http status code ", code)
+
+                            if conf._meta and conf._meta.error_response then
+                                -- Whether or not the original error message is output,
+                                -- always return the configured message
+                                -- so the caller can't guess the real error
+                                body = conf._meta.error_response
+                            end
                         end
 
                         core.response.exit(code, body)

apisix/schema_def.lua

@@ -914,6 +914,17 @@ _M.plugin_injected_schema = {
     ["$comment"] = "this is a mark for our injected plugin schema",
     disable = {
         type = "boolean",
+    },
+    _meta = {
+        type = "object",
+        properties = {
+            error_response = {
+                oneOf = {
+                    { type = "string" },
+                    { type = "object" },
+                }
+            },
+        }
     }
 }
 

docs/en/latest/terminology/plugin.md

@@ -72,6 +72,30 @@ A warning level log as shown below indicates that the request was rejected by th
 ip-restriction exits with http status code 403
 ```
 
+## Plugin Common Configuration
+
+Some common configurations can be applied to the plugin configuration. For example,
+
+```json
+{
+    "jwt-auth": {
+        "_meta": {
+            "error_response": {
+                "message": "Missing credential in request"
+            }
+        }
+    }
+}
+```
+
+the configuration above means customizing the error response from the jwt-auth plugin to '{"message": "Missing credential in request"}'.
+
+### Plugin Common Configuration Under `_meta`
+
+| Name         | Type | Description |
+|--------------|------|-------------|
+| error_response | string/object  | Custom error response |
+
 ## Hot Reload
 
 APISIX Plugins are hot-loaded. This means that there is no need to restart the service if you add, delete, modify plugins, or even if you update the plugin code. To hot-reload, you can send an HTTP request through the [Admin API](../admin-api.md):

docs/zh/latest/terminology/plugin.md

@@ -66,6 +66,30 @@ local _M = {
 
 如果一个请求因为某个插件而被拒绝，会有类似这样的 warn 日志：`ip-restriction exits with http status code 403`。
 
+## 插件通用配置
+
+一些通用的配置可以应用于插件配置。比如说。
+
+````json
+{
+    "jwt-auth": {
+        "_meta": {
+            "error_response": {
+                "message": "Missing credential in request"
+            }
+        }
+    }
+}
+```
+
+上面的配置意味着将 jwt-auth 插件的错误响应自定义为 '{"message": "Missing credential in request"}'。
+
+### 在 `_meta` 下的插件通用配置
+
+| 名称         | 类型 | 描述           |
+|--------------|------|----------------|
+| error_response | string/object  | 自定义错误响应 |
+
 ## 热加载
 
 APISIX 的插件是热加载的，不管你是新增、删除还是修改插件，都不需要重启服务。

t/admin/plugins.t

@@ -265,7 +265,7 @@ plugins:
         }
     }
 --- response_body eval
-qr/\{"metadata_schema":\{"properties":\{"ikey":\{"minimum":0,"type":"number"\},"skey":\{"type":"string"\}\},"required":\["ikey","skey"\],"type":"object"\},"priority":0,"schema":\{"\$comment":"this is a mark for our injected plugin schema","properties":\{"disable":\{"type":"boolean"\},"i":\{"minimum":0,"type":"number"\},"ip":\{"type":"string"\},"port":\{"type":"integer"\},"s":\{"type":"string"\},"t":\{"minItems":1,"type":"array"\}\},"required":\["i"\],"type":"object"\},"version":0.1\}/
+qr/\{"metadata_schema":\{"properties":\{"ikey":\{"minimum":0,"type":"number"\},"skey":\{"type":"string"\}\},"required":\["ikey","skey"\],"type":"object"\},"priority":0,"schema":\{"\$comment":"this is a mark for our injected plugin schema","properties":\{"_meta":\{"properties":\{"error_response":\{"oneOf":\[\{"type":"string"\},\{"type":"object"\}\]\}\},"type":"object"\},"disable":\{"type":"boolean"\},"i":\{"minimum":0,"type":"number"\},"ip":\{"type":"string"\},"port":\{"type":"integer"\},"s":\{"type":"string"\},"t":\{"minItems":1,"type":"array"\}\},"required":\["i"\],"type":"object"\},"version":0.1\}/
 
 
 
@@ -366,7 +366,7 @@ qr/\{"properties":\{"password":\{"type":"string"\},"username":\{"type":"string"\
         }
     }
 --- response_body
-{"priority":1003,"schema":{"$comment":"this is a mark for our injected plugin schema","properties":{"burst":{"minimum":0,"type":"integer"},"conn":{"exclusiveMinimum":0,"type":"integer"},"default_conn_delay":{"exclusiveMinimum":0,"type":"number"},"disable":{"type":"boolean"},"key":{"type":"string"},"key_type":{"default":"var","enum":["var","var_combination"],"type":"string"},"only_use_default_delay":{"default":false,"type":"boolean"}},"required":["conn","burst","default_conn_delay","key"],"type":"object"},"version":0.1}
+{"priority":1003,"schema":{"$comment":"this is a mark for our injected plugin schema","properties":{"_meta":{"properties":{"error_response":{"oneOf":[{"type":"string"},{"type":"object"}]}},"type":"object"},"burst":{"minimum":0,"type":"integer"},"conn":{"exclusiveMinimum":0,"type":"integer"},"default_conn_delay":{"exclusiveMinimum":0,"type":"number"},"disable":{"type":"boolean"},"key":{"type":"string"},"key_type":{"default":"var","enum":["var","var_combination"],"type":"string"},"only_use_default_delay":{"default":false,"type":"boolean"}},"required":["conn","burst","default_conn_delay","key"],"type":"object"},"version":0.1}
 
 
 

t/plugin/plugin.t

@@ -219,3 +219,90 @@ GET /apisix/plugin/blah
     }
 --- response_body
 ok
+
+
+
+=== TEST 7: plugin with custom error message
+--- 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": {
+                        "jwt-auth": {
+                            "_meta": {
+                                "error_response": {
+                                    "message":"Missing credential in request"
+                                }
+                            }
+                        }
+                    },
+                    "upstream": {
+                        "nodes": {
+                            "127.0.0.1:1980": 1
+                        },
+                        "type": "roundrobin"
+                    },
+                    "uri": "/hello"
+                }]]
+                )
+
+            if code >= 300 then
+                ngx.status = code
+            end
+            ngx.say(body)
+        }
+    }
+--- response_body
+passed
+
+
+
+=== TEST 8: verify, missing token
+--- request
+GET /hello
+--- error_code: 401
+--- response_body
+{"message":"Missing credential in request"}
+
+
+
+=== TEST 9: validate custom error message configuration
+--- config
+    location /t {
+        content_by_lua_block {
+            local t = require("lib.test_admin").test
+
+            for _, case in ipairs({
+                {input = true},
+                {input = {
+                    error_response = true
+                }},
+                {input = {
+                    error_response = "OK"
+                }},
+            }) do
+                local code, body = t('/apisix/admin/global_rules/1',
+                    ngx.HTTP_PUT,
+                    {
+                        plugins = {
+                            ["jwt-auth"] = {
+                                _meta = case.input
+                            }
+                        }
+                    }
+                )
+                if code >= 300 then
+                    ngx.print(body)
+                else
+                    ngx.say(body)
+                end
+            end
+        }
+    }
+--- response_body
+{"error_msg":"failed to check the configuration of plugin jwt-auth err: property \"_meta\" validation failed: wrong type: expected object, got boolean"}
+{"error_msg":"failed to check the configuration of plugin jwt-auth err: property \"_meta\" validation failed: property \"error_response\" validation failed: value should match only one schema, but matches none"}
+passed