[Docs] Add featureenv example readme(en) file (main). (#460)

CHANGELOG.md

@@ -15,3 +15,4 @@
 - [Feature: Add disposable metadata transfer support](https://github.com/Tencent/spring-cloud-tencent/pull/430)
 - [Bugfix: Removed unused class for circuit-breaker module](https://github.com/Tencent/spring-cloud-tencent/pull/455)
 - [Optimize: rename opertion EQUAL to EQUALS](https://github.com/Tencent/spring-cloud-tencent/pull/457)
+- [Docs: Add featureenv example readme(en) file](https://github.com/Tencent/spring-cloud-tencent/pull/460)

spring-cloud-tencent-examples/polaris-router-featureenv-example/README-zh.md

@@ -1,5 +1,7 @@
 # 多测试环境样例说明
 
+[English](./README.md) | 简体中文
+
 ## 一、部署结构
 
 <img src="./imgs/structs.png"/>

spring-cloud-tencent-examples/polaris-router-featureenv-example/README.md

@@ -0,0 +1,154 @@
+## A Multi-Feature Environment Example
+
+English | [简体中文](./README-zh.md)
+
+## I. Deployment Structure
+
+<img src="./imgs/structs.png" alt="multi-feature environment structure"/>
+
+As shown in the figure above, there are three environments.
+1. `baseline` environment, including `FrontService`, `MiddleService`, `BackendService`
+2. `feature1` environment, including `MiddleService`, `BackendService`
+3. `feature2` environment, including `FrontService`, `BackendService`
+
+And at the entrance, deploy the `gateway` service.
+
+Three request links.
+1. `baseline` environment link, `Gateway` -> `FrontService`(baseline) -> `MiddleService`(baseline) -> `BackendService`(baseline)
+2. `feature1` environment link, `Gateway` -> `FrontService`(baseline) -> `MiddleService`(feature1) -> `BackendService`(feature1)
+3. `feature2` environment link, `Gateway` -> `FrontService`(feature2) -> `MiddleService`(baseline) -> `BackendService`(feature2)
+
+
+## II. Running
+
+Without any code changes, just start all the applications under `base`, `feature1`, `feature2`, `featureenv-gateway` directly.
+
+By default, the applications point to the official Polaris experience environment, and you can directly view the service registration data at the experience site after a successful launch.
+
+- Console address: http://14.116.241.63:8080/
+  - Account：polaris
+  - Password: polaris
+
+## III. Testing
+
+### Mode 1: Client Request With `featureenv` Label
+
+#### `baseline` environment link
+````
+curl http://127.0.0.1:9999/featureenv-front-example/router/rest
+````
+Response results (base indicates baseline environment)
+````
+featureenv-front-example[base] -> featureenv-middle-example[base] -> featureenv-backend-example[base]
+````
+
+#### `feature1` environment link
+
+Specify the feature environment via the `X-Polaris-Metadata-Transitive-featureenv` request header.
+
+````
+curl -H'X-Polaris-Metadata-Transitive-featureenv:feature1' http://127.0.0.1:9999/featureenv-front-example/router/rest
+````
+Response results
+````
+featureenv-front-example[base] -> featureenv-middle-example[feature1] -> featureenv-backend-example[feature1]
+````
+
+#### `feature2` environment link
+
+Specify the feature environment via the `X-Polaris-Metadata-Transitive-featureenv` request header.
+
+````
+curl -H'X-Polaris-Metadata-Transitive-featureenv:feature2' http://127.0.0.1:9999/featureenv-front-example/router/rest
+````
+Response results
+````
+featureenv-front-example[feature2] -> featureenv-middle-example[base] -> featureenv-backend-example[feature2]
+````
+
+### Mode 2: Gateway traffic staining
+
+Simulate a real-world scenario, assuming that the client request has a uid request parameter and expects:
+1. `uid=1000` requests hit the `feature1` environment
+2. `uid=2000` requests hit the `feature2` environment
+3. requests with other uid hit the `baseline` environment
+
+**Configure coloring rules**
+
+Polaris Configuration Address：http://14.116.241.63:8080/#/filegroup-detail?group=featureenv-gateway&namespace=default
+
+Modify the `rule/staining.json` configuration file and fill in the following rule:
+
+````json
+{
+    "rules":[
+        {
+            "conditions":[
+                {
+                    "key":"${http.query.uid}",
+                    "values":["1000"],
+                    "operation":"EQUAL"
+                }
+            ],
+            "labels":[
+                {
+                    "key":"featureenv",
+                    "value":"feature1"
+                }
+            ]
+        },
+        {
+            "conditions":[
+                {
+                    "key":"${http.query.uid}",
+                    "values":["2000"],
+                    "operation":"EQUAL"
+                }
+            ],
+            "labels":[
+                {
+                    "key":"featureenv",
+                    "value":"feature2"
+                }
+            ]
+        }
+    ]
+}
+````
+
+Just fill out and publish the configuration.
+
+#### `baseline` Environment Link
+````
+curl http://127.0.0.1:9999/featureenv-front-example/router/rest?uid=3000
+````
+Response results (base indicates baseline environment)
+````
+featureenv-front-example[base] -> featureenv-middle-example[base] -> featureenv-backend-example[base]
+````
+
+#### `feature1` Environment Link
+
+Specify the feature environment via the `X-Polaris-Metadata-Transitive-featureenv` request header.
+
+````
+curl http://127.0.0.1:9999/featureenv-front-example/router/rest?uid=1000
+````
+Response results
+````
+featureenv-front-example[base] -> featureenv-middle-example[feature1] -> featureenv-backend-example[feature1]
+````
+
+#### `feature2` Environment Link
+
+Specify the feature environment via the `X-Polaris-Metadata-Transitive-featureenv` request header.
+
+````
+curl http://127.0.0.1:9999/featureenv-front-example/router/rest?uid=2000
+````
+Response results
+````
+featureenv-front-example[feature2] -> featureenv-middle-example[base] -> featureenv-backend-example[feature2]
+````
+
+