add readme

python/examples/pipeline/grpc-gateway/README_CN.md

+# 通过 gRPC-gateway 开启 HTTP 服务
+
+## 安装依赖
+
+### 1. Protobuf 3
+
+在我们提供的容器中需要先安装 `autoconf` ，`automake`，`libtool` ：
+
+```shell
+yum install -y autoconf automake libtool
+```
+
+编译 Protobuf 3：
+
+```shell
+mkdir tmp
+cd tmp
+git clone https://github.com/google/protobuf
+cd protobuf && git submodule update --init --recursive
+./autogen.sh
+./configure
+make
+make check
+sudo make install
+```
+
+### 2. Go packages
+
+设置 `GOPATH`：
+```shell
+export GOPATH=$HOME/go
+export PATH=$PATH:$GOPATH/bin
+```
+下载 packages：
+```shell
+go get -u github.com/grpc-ecosystem/grpc-gateway/protoc-gen-grpc-gateway
+go get -u github.com/grpc-ecosystem/grpc-gateway/protoc-gen-swagger
+go get -u github.com/golang/protobuf/protoc-gen-go
+```
+
+## 生成 gRPC stub 和 反向代理
+
+```shell
+cd gateway
+sh gen_code.sh
+```
+
+## 编译 Go 程序
+
+```
+go build proxy_server.go
+```
+
+## 运行测试
+
+这里以 imdb model ensemble 为例：
+```shell
+cd ../imdb_model_ensemble/
+sh get_data.sh
+python -m paddle_serving_server_gpu.serve --model imdb_cnn_model --port 9292 &> cnn.log &
+python -m paddle_serving_server_gpu.serve --model imdb_bow_model --port 9393 &> bow.log &
+python test_pipeline_server.py &> pipeline.log &
+cd -
+./proxy_server &> gateway.log &
+
+curl -X POST -k http://localhost:8080/pipeline/prediction -d '{"key": ["words"], "value": ["i am very sad | 0"]}'
+```