KinopioHub.cpp/examples/request_reply.cpp at main · skyboooox/KinopioHub.cpp · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
#include <chrono>
#include <cstdlib>
#include <iostream>
#include <thread>

#include <nlohmann/json.hpp>

#include "kinopio/kinopio.hpp"

namespace {

std::string resolveServer() {
  if (const char* value = std::getenv("KINOPIO_NATS_URL")) {
    return value;
  }
  return "nats://demo.nats.io:4222";
}

}  // namespace

int main() {
  kinopio::KinopioOptions options;
  options.servers = {resolveServer()};

  kinopio::KinopioHub hub(options);
  hub.connected(std::chrono::seconds(5));

  auto calculator = hub.getScope("math").getVariable("calculator");

  auto service = calculator.serve([](const kinopio::Payload& request, const kinopio::MessageMetadata&) -> kinopio::Payload {
    const auto& json = std::get<nlohmann::json>(request);
    std::string operation = json.value("operation", "");
    int a = json.value("a", 0);
    int b = json.value("b", 0);

    nlohmann::json result{
        {"operation", operation},
        {"inputs", {{"a", a}, {"b", b}}},
        {"timestamp", std::chrono::duration_cast<std::chrono::milliseconds>(
                         std::chrono::system_clock::now().time_since_epoch())
                         .count()}
    };

    if (operation == "add") {
      result["result"] = a + b;
    } else if (operation == "subtract") {
      result["result"] = a - b;
    } else if (operation == "multiply") {
      result["result"] = a * b;
    } else if (operation == "divide") {
      if (b != 0) {
        result["result"] = a / b;
      } else {
        result["result"] = "Error: Division by zero";
      }
    } else {
      throw std::runtime_error("Unknown operation: " + operation);
    }

    return result;
  });

  std::cout << "Calculator service is running\n";
  std::this_thread::sleep_for(std::chrono::seconds(1));

  auto response1 = calculator.req(nlohmann::json{
      {"operation", "add"},
      {"a", 10},
      {"b", 5}
  });
  std::cout << "Addition result: " << std::get<nlohmann::json>(response1).dump() << '\n';

  auto response2 = calculator.req(nlohmann::json{
      {"operation", "multiply"},
      {"a", 7},
      {"b", 3}
  });
  std::cout << "Multiplication result: " << std::get<nlohmann::json>(response2).dump() << '\n';

  auto response3 = calculator.req(nlohmann::json{
      {"operation", "divide"},
      {"a", 20},
      {"b", 4}
  });
  std::cout << "Division result: " << std::get<nlohmann::json>(response3).dump() << '\n';

  try {
    auto error_response = calculator.req(nlohmann::json{
        {"operation", "invalid"},
        {"a", 1},
        {"b", 2}
    });
  } catch (const std::exception& e) {
    std::cout << "Expected error: " << e.what() << '\n';
  }

  std::cout << "All requests completed!\n";

  std::this_thread::sleep_for(std::chrono::seconds(2));

  service.unsubscribe();
  hub.dispose();
  return 0;
}