grpc point

proto file

.proto file that defines the gRPC service and messages

compile

Use protoc to generate client and server code for both languages

When you compile .proto files using protoc, it generates two Go files: xxx.pb.go and xxx_grpc.pb.go. These files are essential for both client and server implementations in a gRPC service. Here’s how they fit into the architecture:

xxx.pb.go

• Purpose: Contains the Go representations of the protocol buffer messages defined in the .proto file.
• Usage: Used by both client and server to serialize and deserialize the messages.
• Contents:
  • Go structs for each message type.
  • Methods for marshaling and unmarshaling these structs to and from binary format.

xxx_grpc.pb.go

• Purpose: Contains the gRPC service definitions and client/server interfaces.
• Usage:
  • Server: Implements the server-side logic by embedding the generated server interface.
  • Client: Uses the generated client interface to make RPC calls.
• Contents:
  • Server interface with methods corresponding to the RPCs defined in the .proto file.
  • Client interface with methods to call the RPCs.
  • Registration functions to register the server with a gRPC server.
  • Handler functions to handle incoming RPC calls.

client and server

Client Code

• References: Both xxx.pb.go and xxx_grpc.pb.go.
• Functionality:
  • Uses the client interface from xxx_grpc.pb.go to make RPC calls.
  • Constructs request messages using the structs from xxx.pb.go.

Server Code

• References: Both xxx.pb.go and xxx_grpc.pb.go.
• Functionality:
  • Implements the server interface from xxx_grpc.pb.go.
  • Handles incoming requests and constructs response messages using the structs from xxx.pb.go.

Example

In the provided example:

• Client Code (examples/helloworld/greeter_client/main.go):

  • Uses pb.NewGreeterClient from helloworld_grpc.pb.go to create a client.
  • Constructs HelloRequest messages using the struct from helloworld.pb.go.

• Server Code (examples/helloworld/greeter_server/main.go):

  • Implements GreeterServer interface from helloworld_grpc.pb.go.
  • Constructs HelloReply messages using the struct from helloworld.pb.go.

This architecture ensures that both client and server have a consistent and type-safe way to communicate using the protocol buffer messages and gRPC service definitions.