解决grpc gateway 无法protoc问题

$ protoc --go_out=plugins=grpc:../services/ Product.proto

google/protobuf/descriptor.proto: File not found.
google/api/annotations.proto: Import "google/protobuf/descriptor.proto" was not found or had errors.
google/api/annotations.proto:28:8: "google.protobuf.MethodOptions" is not defined.
Product.proto: Import "google/api/annotations.proto" was not found or had errors.

https://github.com/grpc-ecosystem/grpc-gateway/issues/422

Make sure you grab the latest version
curl -OL https://github.com/google/protobuf/releases/download/v3.2.0/protoc-3.2.0-linux-x86_64.zip

Unzip
unzip protoc-3.2.0-linux-x86_64.zip -d protoc3

Move protoc to /usr/local/bin/
sudo mv protoc3/bin/* /usr/local/bin/

Move protoc3/include to /usr/local/include/
sudo mv protoc3/include/* /usr/local/include/

Optional: change owner
sudo chown [user] /usr/local/bin/protoc
sudo chown -R [user] /usr/local/include/google

简单说 之前我的protoc被我放在了$GOPATH/bin下 所以无法找到include下的google文件
解决方式 将protoc安装文件全部放在/usr/local/下