This library aims to enable Metrics-Driven Development for C++ serivices. It implements the Prometheus Data Model, a powerful abstraction on which to collect and expose metrics. We offer the possibility for metrics to collected by Prometheus, but other push/pull collections can be added as plugins.
#include <chrono> #include <map> #include <memory> #include <string> #include <thread> #include "lib/exposer.h" #include "lib/registry.h" int main(int argc, char** argv) { using namespace prometheus; // create an http server running on port 8080 auto exposer = Exposer{8080}; // create a metrics registry with component=main labels applied to all its // metrics auto registry = std::make_shared<Registry>( std::map<std::string, std::string>{{"component", "main"}}); // add a new counter family to the registry (families combine values with the // same name, but distinct labels) auto counterFamily = registry->add_counter( "time_running_seconds", "How many seconds is this server running?", {}); // add a counter to the metric auto secondCounter = counterFamily->add({}); // ask the exposer to scrape the registry on incoming scrapes exposer.registerCollectable(registry); for (;;) { std::this_thread::sleep_for(std::chrono::seconds(1)); // increment the counter by one (second) secondCounter->inc(); } return 0; }Install bazel. Bazel makes it trivial to add this repo to your project as a dependency. Just add the following to your WORKSPACE
git_repository( name = "prometheus-cpp", remote = "https://github.com/jupp0r/prometheus-cpp.git", branch = "master", ) You can also check out this repo and build the library using
bazel build lib:allor run the unit tests using
bazel test //tests:prometheus_test There is also an integration test that uses telegraf to scrape a sample server. With telegraf installed, it can be run using
bazel test //tests/integration:scrape_test There's a benchmark suite you can run:
bazel run -c opt tests/benchmark/benchmarks INFO: Found 1 target... Target //tests/benchmark:benchmarks up-to-date: bazel-bin/tests/benchmark/benchmarks INFO: Elapsed time: 1.682s, Critical Path: 1.56s INFO: Running command line: bazel-bin/tests/benchmark/benchmarks Run on (8 X 2300 MHz CPU s) 2016-10-17 15:56:49 Benchmark Time CPU Iterations -------------------------------------------------------------------- BM_Counter_Increment 11 ns 11 ns 62947942 BM_Counter_Collect 84 ns 84 ns 8221752 BM_Gauge_Increment 11 ns 11 ns 61384663 BM_Gauge_Decrement 11 ns 11 ns 62148197 BM_Gauge_SetToCurrentTime 199 ns 198 ns 3589670 BM_Gauge_Collect 86 ns 85 ns 7469136 BM_Histogram_Observe/0 122 ns 122 ns 5839855 BM_Histogram_Observe/1 116 ns 115 ns 5806623 BM_Histogram_Observe/8 126 ns 126 ns 5781588 BM_Histogram_Observe/64 138 ns 138 ns 4895550 BM_Histogram_Observe/512 228 ns 228 ns 2992898 BM_Histogram_Observe/4k 959 ns 958 ns 642231 BM_Histogram_Collect/0 328 ns 327 ns 2002792 BM_Histogram_Collect/1 356 ns 354 ns 1819032 BM_Histogram_Collect/8 1553 ns 1544 ns 454921 BM_Histogram_Collect/64 10389 ns 10287 ns 66759 BM_Histogram_Collect/512 75795 ns 75093 ns 9075 BM_Histogram_Collect/4k 615853 ns 610277 ns 1222 BM_Registry_CreateFamily 195 ns 182 ns 3843894 BM_Registry_CreateCounter/0 319 ns 317 ns 1914132 BM_Registry_CreateCounter/1 2146 ns 2131 ns 408432 BM_Registry_CreateCounter/8 8936 ns 8837 ns 82439 BM_Registry_CreateCounter/64 72589 ns 72010 ns 9248 BM_Registry_CreateCounter/512 694323 ns 686655 ns 1056 BM_Registry_CreateCounter/4k 18246638 ns 18150525 ns 40 Alpha
- parts of the library are instrumented by itself (bytes scraped, number of scrapes, scrape request latencies)
- there is a working example that prometheus successfully scrapes
- gauge, counter and histogram metrics are implemented, summaries aren't
- thread safety is missing in registries and metric families (you'd have to lock access yourself for now)
MIT