syntax = "proto3";

package GSB_API;

/* Exposed by Golem Service Bus API implementation */
service Bus {
  /* Register a service within the bus */
  rpc Register (RegisterRequest) returns (RegisterReply);

  /* Unregister a service from the bus */
  rpc Unregister (UnregisterRequest) returns (UnregisterReply);

  /* Call a local or remote service method */
  rpc ServiceCall (CallRequest) returns (CallReply);

  /* Subscribe to a broadcast topic */
  rpc Subscribe (SubscribeRequest) returns (SubscribeReply);

  /* Unsubscribe from a broadcast topic */
  rpc Unsubscribe (UnsubscribeRequest) returns (UnsubscribeReply);

  /* Broadcast a message to everyone subscribed to a topic */
  rpc Broadcast (BroadcastRequest) returns (BroadcastReply);
}

/* Exposed by registering services */
service Service {
  rpc Call (CallRequest) returns (CallReply);
  rpc Check (Ping) returns (Pong);
}

message Packet {
  oneof packet {
    Hello hello = 1;
    RegisterRequest register_request = 2;
    RegisterReply register_reply = 3;
    UnregisterRequest unregister_request = 4;
    UnregisterReply unregister_reply = 5;
    CallRequest call_request = 6;
    CallReply call_reply = 7;
    SubscribeRequest subscribe_request = 8;
    SubscribeReply subscribe_reply = 9;
    UnsubscribeRequest unsubscribe_request = 10;
    UnsubscribeReply unsubscribe_reply = 11;
    BroadcastRequest broadcast_request = 12;
    BroadcastReply broadcast_reply = 13;

    Ping ping = 14;
    Pong pong = 15;
  }
}

enum RegisterReplyCode {
  REGISTERED_OK = 0;
  REGISTER_BAD_REQUEST = 400; // e.g. invalid name
  REGISTER_CONFLICT = 409;  // already registered
}

enum UnregisterReplyCode {
  UNREGISTERED_OK = 0;
  NOT_REGISTERED = 404;
}

enum CallReplyCode {
  CALL_REPLY_OK = 0;
  CALL_REPLY_BAD_REQUEST = 400; // e.g. duplicate request ID, service not found etc.
  SERVICE_FAILURE = 500;  // e.g. service did not respond in time
}

enum CallReplyType {
  FULL = 0;  // a single response or end of stream
  PARTIAL = 1;  // i.e. a streaming response
}

enum SubscribeReplyCode {
  SUBSCRIBED_OK = 0;
  SUBSCRIBE_BAD_REQUEST = 400;  // e.g. invalid topic name
}

enum UnsubscribeReplyCode {
  UNSUBSCRIBED_OK = 0;
  NOT_SUBSCRIBED = 404;
}

enum BroadcastReplyCode {
  BROADCAST_OK = 0;
  BROADCAST_BAD_REQUEST = 400;  // e.g. invalid topic name
}

message RegisterRequest {
  string service_id = 1;
}

message RegisterReply {
  RegisterReplyCode code = 1;
  string message = 2;  // in case of errors
}

message UnregisterRequest {
  string service_id = 1;
}

message UnregisterReply {
  UnregisterReplyCode code = 1;
}

message CallRequest {
  string caller = 1;
  string address = 2;
  string request_id = 3;
  bytes data = 4;
  bool no_reply = 5;
}

message CallReply {
  string request_id = 1;
  CallReplyCode code = 2;
  CallReplyType reply_type = 3;
  bytes data = 4;
}

message SubscribeRequest {
  string topic = 1;
}

message SubscribeReply {
  SubscribeReplyCode code = 1;
  string message = 2;  // in case of errors
}

message UnsubscribeRequest {
  string topic = 1;
}

message UnsubscribeReply {
  UnsubscribeReplyCode code = 1;
}

message BroadcastRequest {
  string caller = 1;
  bytes data = 2;
  string topic = 3;
}

message BroadcastReply {
  BroadcastReplyCode code = 1;
  string message = 2;  // in case of errors
}

message Ping {}

message Pong {}

message Hello {
  string name = 1;
  string version = 2;
  bytes instance_id = 3;
}