feat(plugin): add degradation switch for ext-plugin (#5897)

Co-authored-by: tzssangglass <tzssangglass@gmail.com>
Co-authored-by: 罗泽轩 <spacewanderlzx@gmail.com>
Co-authored-by: liushan03 <liushan03@meicai.cn>

apisix/plugins/ext-plugin/init.lua

@@ -99,6 +99,7 @@ local schema = {
             },
             minItems = 1,
         },
+        allow_degradation = {type = "boolean", default = false}
     },
 }
 
@@ -700,6 +701,10 @@ function _M.communicate(conf, ctx, plugin_name)
 
         if not core.string.find(err, "conf token not found") then
             core.log.error(err)
+            if conf.allow_degradation then
+                core.log.warn("Plugin Runner is wrong, allow degradation")
+                return
+            end
             return 503
         end
 
@@ -708,6 +713,10 @@ function _M.communicate(conf, ctx, plugin_name)
     end
 
     core.log.error(err)
+    if conf.allow_degradation then
+        core.log.warn("Plugin Runner is wrong after " .. tries .. " times retry, allow degradation")
+        return
+    end
     return 503
 end
 

docs/en/latest/plugins/ext-plugin-pre-req.md

@@ -43,6 +43,7 @@ The result of external plugins execution will affect the behavior of the current
 | Name      | Type          | Requirement | Default    | Valid                                                                    | Description                                                                                                                                         |
 | --------- | ------------- | ----------- | ---------- | ------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------- |
 | conf     | array        | optional    |              | [{"name": "ext-plugin-A", "value": "{\"enable\":\"feature\"}"}] |     The plugins list which will be executed at the plugin runner with their configuration    |
+| allow_degradation              | boolean  | optional                                | false       |                                                                     | Whether to enable plugin degradation when the plugin runner is temporarily unavailable. Allow requests to continue when the value is set to true, default false. |
 
 ## How To Enable
 

docs/zh/latest/plugins/ext-plugin-pre-req.md

@@ -42,6 +42,7 @@ External Plugins 执行的结果会影响当前请求的行为。
 | 名称      | 类型          | 必选项 | 默认值    | 有效值                                                                    | 描述                                                                                                                                         |
 | --------- | ------------- | ----------- | ---------- | ------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------- |
 | conf     | array        | 可选    |              | [{"name": "ext-plugin-A", "value": "{\"enable\":\"feature\"}"}] |     在 Plugin Runner 内执行的插件列表的配置 |
+| allow_degradation              | boolean  | 可选                                | false       |                                                                     | 当 Plugin Runner 临时不可用时是否允许请求继续。当值设置为 true 时则自动允许请求继续，默认值是 false。|
 
 ## 如何启用
 

t/plugin/ext-plugin/sanity.t

@@ -571,3 +571,125 @@ qr/get conf token: 233 conf: \[(\{"value":"bar","name":"foo"\}|\{"name":"foo","v
             end
         }
     }
+
+
+
+=== TEST 19: default allow_degradation
+--- config
+    location /t {
+        content_by_lua_block {
+            local json = require("toolkit.json")
+            local t = require("lib.test_admin")
+
+            local code, message, res = t.test('/apisix/admin/routes/1',
+                ngx.HTTP_PUT,
+                 [[{
+                    "uri": "/hello",
+                    "plugins": {
+                        "ext-plugin-post-req": {
+                            "conf": [
+                                {"name":"foo", "value":"bar"},
+                                {"name":"cat", "value":"dog"}
+                            ]
+                        }
+                    },
+                    "upstream": {
+                        "nodes": {
+                            "127.0.0.1:1980": 1
+                        },
+                        "type": "roundrobin"
+                    }
+                }]]
+            )
+
+            if code >= 300 then
+                ngx.status = code
+                ngx.say(message)
+                return
+            end
+
+            ngx.say(message)
+        }
+    }
+--- response_body
+passed
+
+
+
+=== TEST 20: ext-plugin wrong, req reject
+--- request
+GET /hello
+--- extra_stream_config
+    server {
+        listen unix:$TEST_NGINX_HTML_DIR/nginx.sock1;
+
+        content_by_lua_block {
+            local ext = require("lib.ext-plugin")
+            ext.go({})
+        }
+    }
+--- error_code: 503
+--- error_log eval
+qr/failed to connect to the unix socket/
+
+
+
+=== TEST 21: open allow_degradation
+--- config
+    location /t {
+        content_by_lua_block {
+            local json = require("toolkit.json")
+            local t = require("lib.test_admin")
+
+            local code, message, res = t.test('/apisix/admin/routes/1',
+                ngx.HTTP_PUT,
+                 [[{
+                    "uri": "/hello",
+                    "plugins": {
+                        "ext-plugin-post-req": {
+                            "conf": [
+                                {"name":"foo", "value":"bar"},
+                                {"name":"cat", "value":"dog"}
+                            ],
+                            "allow_degradation": true
+                        }
+                    },
+                    "upstream": {
+                        "nodes": {
+                            "127.0.0.1:1980": 1
+                        },
+                        "type": "roundrobin"
+                    }
+                }]]
+            )
+
+            if code >= 300 then
+                ngx.status = code
+                ngx.say(message)
+                return
+            end
+
+            ngx.say(message)
+        }
+    }
+--- response_body
+passed
+
+
+
+=== TEST 22: ext-plugin wrong, req access
+--- request
+GET /hello
+--- extra_stream_config
+    server {
+        listen unix:$TEST_NGINX_HTML_DIR/nginx.sock1;
+
+        content_by_lua_block {
+            local ext = require("lib.ext-plugin")
+            ext.go({})
+        }
+    }
+--- response_body
+hello world
+--- error_log eval
+qr/Plugin Runner.*allow degradation/