.proto add

proto/calculator.proto

+syntax = "proto3";
+
+package calculator;
+
+option java_package = "com.calculator.multiplication.generated";
+option java_multiple_files = true;
+
+service Calculator {
+  rpc Add (Numbers) returns (Result);
+  rpc Multiply (Numbers) returns (Result);
+
+  rpc GetOperationHistory (Empty) returns (stream OperationHistory);
+}
+
+message Numbers {
+  int32 a = 1;
+  int32 b = 2;
+}
+
+message Result {
+  int32 value = 1;
+  string operation = 2;
+}
+
+message OperationHistory {
+  string service_name = 1;
+  repeated Operation operations = 2;
+}
+
+message Operation {
+  string type = 1;
+  int32 a = 2;
+  int32 b = 3;
+  int32 result = 4;
+  string timestamp = 5;
+}
+
+message Empty {}
\ No newline at end of file