78 lines
2.9 KiB
C++
78 lines
2.9 KiB
C++
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#include <array>
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#include <chrono>
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#include <cstdlib>
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#include <memory>
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#include <string>
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#include <thread>
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#include "prometheus/client_metric.h"
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#include "prometheus/counter.h"
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#include "prometheus/exposer.h"
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#include "prometheus/family.h"
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#include "prometheus/info.h"
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#include "prometheus/registry.h"
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int main() {
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using namespace prometheus;
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// create a http server running on port 8080
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Exposer exposer{"127.0.0.1:8080"};
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// create a metrics registry
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// @note it's the users responsibility to keep the object alive
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auto registry = std::make_shared<Registry>();
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// add a new counter family to the registry (families combine values with the
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// same name, but distinct label dimensions)
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//
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// @note please follow the metric-naming best-practices:
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// https://prometheus.io/docs/practices/naming/
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auto& packet_counter = BuildCounter()
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.Name("observed_packets_total")
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.Help("Number of observed packets")
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.Register(*registry);
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// add and remember dimensional data, incrementing those is very cheap
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auto& tcp_rx_counter =
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packet_counter.Add({{"protocol", "tcp"}, {"direction", "rx"}});
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auto& tcp_tx_counter =
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packet_counter.Add({{"protocol", "tcp"}, {"direction", "tx"}});
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auto& udp_rx_counter =
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packet_counter.Add({{"protocol", "udp"}, {"direction", "rx"}});
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auto& udp_tx_counter =
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packet_counter.Add({{"protocol", "udp"}, {"direction", "tx"}});
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// add a counter whose dimensional data is not known at compile time
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// nevertheless dimensional values should only occur in low cardinality:
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// https://prometheus.io/docs/practices/naming/#labels
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auto& http_requests_counter = BuildCounter()
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.Name("http_requests_total")
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.Help("Number of HTTP requests")
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.Register(*registry);
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auto& version_info = BuildInfo()
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.Name("versions")
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.Help("Static info about the library")
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.Register(*registry);
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version_info.Add({{"prometheus", "1.0"}});
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// ask the exposer to scrape the registry on incoming HTTP requests
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exposer.RegisterCollectable(registry);
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for (;;) {
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std::this_thread::sleep_for(std::chrono::seconds(1));
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const auto random_value = std::rand();
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if (random_value & 1) tcp_rx_counter.Increment();
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if (random_value & 2) tcp_tx_counter.Increment();
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if (random_value & 4) udp_rx_counter.Increment();
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if (random_value & 8) udp_tx_counter.Increment();
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const std::array<std::string, 4> methods = {"GET", "PUT", "POST", "HEAD"};
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auto method = methods.at(random_value % methods.size());
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// dynamically calling Family<T>.Add() works but is slow and should be
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// avoided
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http_requests_counter.Add({{"method", method}}).Increment();
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}
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return 0;
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}
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