feat(proxy-mirror): support prefix mode

apisix/plugins/proxy-mirror.lua

@@ -33,6 +33,12 @@ local schema = {
             type = "string",
             pattern = [[^/[^?&]+$]],
         },
+        path_concat_mode = {
+            type = "string",
+            default = "replace",
+            enum = {"replace", "prefix"},
+            description = "the concatenation mode for custom path"
+        },
         sample_ratio = {
             type = "number",
             minimum = 0.00001,
@@ -83,8 +89,13 @@ end
 
 
 local function enable_mirror(ctx, conf)
-    ctx.var.upstream_mirror_uri = resolver_host(conf.host) .. (conf.path or ctx.var.uri) ..
-                                ctx.var.is_args .. (ctx.var.args or '')
+    if conf.path and conf.path_concat_mode == "prefix" then
+        ctx.var.upstream_mirror_uri = resolver_host(conf.host) .. conf.path .. ctx.var.uri ..
+                                    ctx.var.is_args .. (ctx.var.args or '')
+    else
+        ctx.var.upstream_mirror_uri = resolver_host(conf.host) .. (conf.path or ctx.var.uri) ..
+                                    ctx.var.is_args .. (ctx.var.args or '')
+    end
 
     if has_mod then
         apisix_ngx_client.enable_mirror()

docs/en/latest/plugins/proxy-mirror.md

@@ -41,6 +41,7 @@ The response returned by the mirror request is ignored.
 |--------------|--------|----------|---------|--------------|---------------------------------------------------------------------------------------------------------------------------|
 | host         | string | True     |         |              | Address of the mirror service. It needs to contain the scheme but without the path. For example, `http://127.0.0.1:9797`. |
 | path         | string | False    |         |              | Path of the mirror request. If unspecified, current path will be used.                                                    |
+| path_concat_mode | string | False   |   replace     | ["replace", "prefix"]       | If the path of a mirror request is specified, set the concatenation mode of request paths. The `replace` mode will directly use `path` as the path of the mirror request. The `prefix` mode will use the `path` + `source request URI` as the path to the mirror request.  |
 | sample_ratio | number | False    | 1       | [0.00001, 1] | Ratio of the requests that will be mirrored.                                                                              |
 
 You can customize the proxy timeouts for the mirrored sub-requests by configuring the `plugin_attr` key in your configuration file (`conf/config.yaml`). This can be used for mirroring traffic to a slow backend.

docs/zh/latest/plugins/proxy-mirror.md

@@ -42,6 +42,7 @@ description: 本文介绍了 Apache APISIX proxy-mirror 插件的相关操作，
 | ---- | ------ | ------ | ------ | ------ | ------------------------------------------------------------------------------------------------------- |
 | host | string | 是   |        |        | 指定镜像服务的地址，地址中需要包含 `schema`（`http` 或 `https`），但不能包含 `path` 部分。例如 `http://127.0.0.1:9797`。 |
 | path | string | 否   |        |        | 指定镜像请求的路径。如果不指定，则默认会使用当前路径。 |
+| path_concat_mode | string | 否   |   replace     | ["replace", "prefix"]       | 当指定镜像请求的路径时，设置请求路径的拼接模式。`replace` 模式将会直接使用 `path` 作为镜像请求的路径。`prefix` 模式将会使用 `path` + `来源请求 URI` 作为镜像请求的路径。  |
 | sample_ratio | number | 否    | 1       |  [0.00001, 1]     | 镜像请求的采样率。当设置为 `1` 时为全采样。 |
 
 ## 启用插件

t/plugin/proxy-mirror.t

@@ -786,3 +786,59 @@ GET /hello
 hello world
 --- error_log
 dns resolver resolves domain: not-find-domian.notfind error:
+
+
+
+=== TEST 27: custom path with prefix path_concat_mode
+--- 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": {
+                            "proxy-mirror": {
+                               "host": "http://127.0.0.1:1986",
+                               "path": "/a",
+                               "path_concat_mode": "prefix"
+                            }
+                        },
+                        "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 28: hit route with prefix path_concat_mode
+--- request
+GET /hello
+--- response_body
+hello world
+--- error_log
+uri: /a/hello,
+
+
+
+=== TEST 29: hit route with args and prefix path_concat_mode
+--- request
+GET /hello?a=1
+--- response_body
+hello world
+--- error_log
+uri: /a/hello?a=1