services/currency/proto/currency.proto

syntax = "proto3";

package currency;

option go_package = "./proto;currency";

service Currency {
	rpc Rates(RatesRequest) returns (RatesResponse) {}
	rpc Convert(ConvertRequest) returns (ConvertResponse) {}
}

// Rates returns the currency rates for a given code e.g USD
message RatesRequest {
	// The currency code to get rates for
	string code = 1;
}

message RatesResponse {
	string code = 1;
	// The rates for the given code
	map<string, double> rates = 2;
}


// Convert returns the currency conversion rate between two pairs e.g USD/GBP
message ConvertRequest {
	// base code to convert from
	string from = 1;
	// target code to convert to
	string to = 2;
	// optional amoun to convert
	double amount = 3;
}

message ConvertResponse {
	// the base code
	string from = 1;
	// the target code
	string to = 2;
	// conversion rate
	double rate = 3;
	// converted amount if specified
	double amount = 4;
}