feat(proxy-mirror): support mirror requests sample_ratio

apisix/plugins/proxy-mirror.lua

@@ -15,7 +15,7 @@
 -- limitations under the License.
 --
 local core          = require("apisix.core")
-
+local math_random = math.random
 local plugin_name   = "proxy-mirror"
 
 local schema = {
@@ -26,6 +26,12 @@ local schema = {
             pattern = [[^http(s)?:\/\/[a-zA-Z0-9][-a-zA-Z0-9]{0,62}]]
                       .. [[(\.[a-zA-Z0-9][-a-zA-Z0-9]{0,62})+(:[0-9]{1,5})?$]],
         },
+        sample_ratio = {
+            type = "number",
+            minimum = 0.00001,
+            maximum = 1,
+            default = 1,
+        },
     },
     required = {"host"},
     minProperties = 1,
@@ -53,7 +59,18 @@ function _M.rewrite(conf, ctx)
     core.log.info("proxy mirror plugin rewrite phase, conf: ", core.json.delay_encode(conf))
 
     ctx.var.upstream_host = ctx.var.host
-    ctx.var.upstream_mirror_host = conf.host
+
+    if not conf.sample_ratio or conf.sample_ratio == 1 then
+        ctx.var.upstream_mirror_host = conf.host
+    else
+        local val = math_random()
+        core.log.info("mirror request sample_ratio conf: ", conf.sample_ratio,
+                                ", random value: ", val)
+        if val < conf.sample_ratio then
+            ctx.var.upstream_mirror_host = conf.host
+        end
+    end
+
 end
 
 

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

@@ -29,13 +29,14 @@ The proxy-mirror plugin, which provides the ability to mirror client requests.
 
 | Name | Type   | Requirement | Default | Valid | Description                                                                                                                 |
 | ---- | ------ | ----------- | ------- | ----- | --------------------------------------------------------------------------------------------------------------------------- |
-| host | string | optional    |         |       | Specify a mirror service address, e.g. http://127.0.0.1:9797 (address needs to contain schema: http or https, not URI part) |
+| host | string | required    |         |       | Specify a mirror service address, e.g. http://127.0.0.1:9797 (address needs to contain scheme: http or https, and without the path part) |
+| sample_ratio | number | optional    | 1       |  [0.00001, 1]     | the sample ratio that requests will be mirrored. |
 
 ### Examples
 
 #### Enable the plugin
 
-1:  enable the proxy-mirror plugin for a specific route :
+example 1:  enable the proxy-mirror plugin for a specific route :
 
 ```shell
 curl http://127.0.0.1:9080/apisix/admin/routes/1  -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '

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

@@ -30,6 +30,7 @@ title: proxy-mirror
 | 名称 | 类型   | 必选项 | 默认值 | 有效值 | 描述                                                                                                    |
 | ---- | ------ | ------ | ------ | ------ | ------------------------------------------------------------------------------------------------------- |
 | host | string | 必须   |        |        | 指定镜像服务地址，例如：http://127.0.0.1:9797（地址中需要包含 schema ：http或https，不能包含 URI 部分） |
+| sample_ratio | number | 可选    | 1       |  [0.00001, 1]     | 镜像请求采样率 |
 
 ### 示例
 

t/lib/server.lua

@@ -18,6 +18,7 @@ local json_decode = require("toolkit.json").decode
 local json_encode = require("toolkit.json").encode
 
 local _M = {}
+local count = 0
 
 
 local function inject_headers()
@@ -425,6 +426,17 @@ function _M._well_known_openid_configuration()
 end
 
 
+function _M.stat_count()
+    local action = ngx.var.arg_action
+    if action == "reset" then
+        count = 0
+    elseif action == "inc" then
+        count = count + 1
+    end
+    ngx.print(count)
+end
+
+
 -- Please add your fake upstream above
 function _M.go()
     local action = string.sub(ngx.var.uri, 2)

t/plugin/proxy-mirror.t

@@ -34,6 +34,7 @@ add_block_preprocessor(sub {
         location / {
             content_by_lua_block {
                 local core = require("apisix.core")
+                local http = require("resty.http")
 
                 core.log.info("upstream_http_version: ", ngx.req.http_version())
 
@@ -48,8 +49,17 @@ add_block_preprocessor(sub {
                     core.log.info(v, ": ", headers_tab[v])
                 end
 
-                core.log.info("uri: ", ngx.var.uri)
+                core.log.info("uri: ", ngx.var.request_uri)
                 ngx.say("hello world")
+
+                local httpc = http.new()
+                local url = "http://127.0.0.1:1980/stat_count?action=inc"
+                local res, err = httpc:request_uri(url, {method = "GET"})
+                if not res then
+                    core.log.error(err)
+                else
+                    core.log.info("currently stat count is ", res.body)
+                end
             }
         }
     }
@@ -445,3 +455,163 @@ GET /t
 passed
 --- no_error_log
 [error]
+
+
+
+=== TEST 13: sanity check (invalid sample_ratio)
+--- 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",
+                               "sample_ratio": 10
+                            }
+                        },
+                        "upstream": {
+                            "nodes": {
+                                "127.0.0.1:1980": 1
+                            },
+                            "type": "roundrobin"
+                        },
+                        "uri": "/hello"
+                   }]]
+                   )
+
+               if code >= 300 then
+                   ngx.status = code
+               end
+               ngx.print(body)
+           }
+       }
+--- request
+GET /t
+--- error_code: 400
+--- response_body
+{"error_msg":"failed to check the configuration of plugin proxy-mirror err: property \"sample_ratio\" validation failed: expected 10 to be smaller than 1"}
+--- no_error_log
+[error]
+
+
+
+=== TEST 14: set mirror requests sample_ratio to 1
+--- 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",
+                               "sample_ratio": 1
+                            }
+                        },
+                        "upstream": {
+                            "nodes": {
+                                "127.0.0.1:1980": 1
+                            },
+                            "type": "roundrobin"
+                        },
+                        "uri": "/hello"
+                   }]]
+                   )
+
+               if code >= 300 then
+                   ngx.status = code
+               end
+               ngx.say(body)
+           }
+       }
+--- request
+GET /t
+--- error_code: 200
+--- response_body
+passed
+--- no_error_log
+[error]
+
+
+
+=== TEST 15: hit route with sample_ratio 1
+--- request
+GET /hello?sample_ratio=1
+--- error_code: 200
+--- response_body
+hello world
+--- error_log_like eval
+qr/uri: \/hello\?sample_ratio=1/
+
+
+
+=== TEST 16: set mirror requests sample_ratio to 0.5
+--- config
+       location /t {
+           content_by_lua_block {
+                local http = require("resty.http")
+               local core = require("apisix.core")
+               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",
+                               "sample_ratio": 0.5
+                            }
+                        },
+                        "upstream": {
+                            "nodes": {
+                                "127.0.0.1:1980": 1
+                            },
+                            "type": "roundrobin"
+                        },
+                        "uri": "/hello"
+                   }]]
+                   )
+
+               if code == 200 then
+                    -- reset count
+                    local count = 0
+                    local httpc = http.new()
+                    local url = "http://127.0.0.1:1980/stat_count?action=reset"
+                    local res, err = httpc:request_uri(url, {method = "GET"})
+                    if not res then
+                        core.log.error(err)
+                    else
+                        core.log.info("reset the mirror request stat count to " .. res.body)
+                        count = res.body
+                    end
+
+                   for i = 1, 200 do
+                       t('/hello?sample_ratio=0.5', ngx.HTTP_GET)
+                   end
+
+                    url = "http://127.0.0.1:1980/stat_count"
+                    res, err = httpc:request_uri(url, {method = "GET"})
+                    if not res then
+                        core.log.error(err)
+                    else
+                        core.log.info("the mirror request stat count is " .. res.body)
+                        count = res.body
+                    end
+                   assert(count >= 75 and count <= 125)
+               elseif code >= 300 then
+                   ngx.status = code
+               end
+               ngx.say(body)
+           }
+       }
+--- request
+GET /t
+--- error_code: 200
+--- response_body
+passed
+--- error_log_like eval
+qr/(uri: \/hello\?sample_ratio=0\.5){75,125}/
+--- timeout: 60