Merge pull request #105 from jupp0r/replace-protobuf

Remove protobuf dependency

This change removes the protobuf wire format, as it's no longer supported in prometheus 2.0. It uses this as an opportunity to remove protobuf as an external dependency all together, which will make integration into existing code bases that already use protobuf much more palatable.

Author: jupp0r

.gitmodules

@@ -4,6 +4,3 @@
 [submodule "civetweb"]
 	path = 3rdparty/civetweb
 	url = https://github.com/civetweb/civetweb.git
-[submodule "prometheus_client_model"]
-	path = 3rdparty/prometheus_client_model
-	url = https://github.com/prometheus/client_model.git

.travis.yml

@@ -17,14 +17,6 @@ install:
   - sudo apt-get update
   - sudo apt-get install -y gcc-5 g++-5
   - sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-5 1 --slave /usr/bin/g++ g++ /usr/bin/g++-5
-  - wget https://github.com/google/protobuf/archive/v3.1.0.tar.gz
-  - tar xzf v3.1.0.tar.gz
-  - cd protobuf-3.1.0
-  - ./autogen.sh
-  - ./configure --prefix=/usr
-  - make -j 4
-  - sudo make install
-  - cd ..
   - sudo add-apt-repository -y ppa:webupd8team/java
   - echo "oracle-java8-installer shared/accepted-oracle-license-v1-1 select true" | sudo debconf-set-selections
   - sudo apt-get install -o Dpkg::Options::="--force-confnew" -y oracle-java8-installer

3rdparty/prometheus_client_model

@@ -11,7 +11,6 @@ cc_library(
         "lib/handler.h",
         "lib/histogram.cc",
         "lib/histogram_builder.cc",
-        "lib/protobuf_delimited_serializer.cc",
         "lib/registry.cc",
         "lib/summary.cc",
         "lib/summary_builder.cc",
@@ -25,7 +24,5 @@ cc_library(
     visibility = ["//visibility:public"],
     deps = [
         "@civetweb//:civetweb",
-        "@com_google_protobuf//:protobuf",
-        "@prometheus_client_model//:prometheus_client_model",
     ],
 )

BUILD

@@ -10,8 +10,10 @@ if(NOT DEFINED CMAKE_CXX_STANDARD AND UNIX)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
 endif()
 
+set(CMAKE_THREAD_PREFER_PTHREAD TRUE)
+find_package(Threads)
+
 find_package(GoogleBenchmark)
-find_package(Protobuf REQUIRED)
 find_package(ZLIB REQUIRED)
 find_package(Telegraf)
 
@@ -64,6 +66,10 @@ target_include_directories(gmock_main
     3rdparty/googletest/googlemock
 )
 
+target_link_libraries(gmock_main PRIVATE
+  ${CMAKE_THREAD_LIBS_INIT}
+)
+
 # prometheus-cpp
 
 add_subdirectory(lib)

CMakeLists.txt

@@ -66,11 +66,7 @@ the [travis build script](.travis.yml) might help.
 
 ### via CMake
 
-One prerequisite for performing the build using CMake is
-having [Protocol Buffers](https://github.com/google/protobuf) >= 3.0
-installed. See the [travis build script](.travis.yml) for how to build
-it from source, or use your operating systems package manager to
-install it.
+For CMake builds don't forget to fetch the submodules first. Then build as usual.
 
 ``` shell
 # fetch third-party dependencies
@@ -126,8 +122,6 @@ cc_binary(
 When you call `prometheus_cpp_repositories()` in your `WORKSPACE` file,
 you introduce the following dependencies to your project:
 
-* `load_com_google_protobuf()` for Google protobuf
-* `load_prometheus_client_model()` for Prometheus data model artifacts
 * `load_civetweb()` for Civetweb
 * `load_com_google_googletest()` for Google gtest
 * `load_com_google_googlebenchmark()` for Googlebenchmark
@@ -211,17 +205,6 @@ Alpha
 
 ## FAQ
 
-### Why do you not provide a `protobuf` version as a submodule in `3rdparty`?
-
-We opted against the submodule solution for protobuf, because
-otherwise ABI compatibiliy issues would force all consumers of
-`prometheus-cpp` to use exactly the same protobuf version as the one
-inside the submodule if they were using protobuf on its own.
-
-To phrase it differently, this library should not control the exact
-version, but the executable linking against it should determine a
-version that other libraries also link against.
-
 ## License
 
 MIT

README.md

@@ -0,0 +1,80 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+#include <tuple>
+#include <vector>
+
+#include "prometheus/metric_type.h"
+
+namespace prometheus {
+
+struct ClientMetric {
+
+  // Label
+
+  struct Label {
+    std::string name;
+    std::string value;
+
+    bool operator==(const Label& rhs) const {
+      return std::tie(name, value) == std::tie(rhs.name, rhs.value);
+    }
+  };
+  std::vector<Label> label;
+
+  // Counter
+
+  struct Counter {
+    double value = 0.0;
+  };
+  Counter counter;
+
+  // Gauge
+
+  struct Gauge {
+    double value = 0.0;
+  };
+  Gauge gauge;
+
+  // Summary
+
+  struct Quantile {
+    double quantile = 0.0;
+    double value = 0.0;
+  };
+
+  struct Summary {
+    std::uint64_t sample_count = 0;
+    double sample_sum = 0.0;
+    std::vector<Quantile> quantile;
+  };
+  Summary summary;
+
+  // Histogram
+
+  struct Bucket {
+    std::uint64_t cumulative_count = 0;
+    double upper_bound = 0.0;
+  };
+
+  struct Histogram {
+    std::uint64_t sample_count = 0;
+    double sample_sum = 0.0;
+    std::vector<Bucket> bucket;
+  };
+  Histogram histogram;
+
+  // Untyped
+
+  struct Untyped {
+    double value = 0;
+  };
+  Untyped untyped;
+
+  // Timestamp
+
+  std::int64_t timestamp_ms = 0;
+};
+
+}  // namespace prometheus

include/prometheus/client_metric.h

@@ -2,19 +2,15 @@
 
 #include <vector>
 
-namespace io {
 namespace prometheus {
-namespace client {
-class MetricFamily;
-}
-}
+struct MetricFamily;
 }
 
 namespace prometheus {
 
 class Collectable {
  public:
   virtual ~Collectable() = default;
-  virtual std::vector<io::prometheus::client::MetricFamily> Collect() = 0;
+  virtual std::vector<MetricFamily> Collect() = 0;
 };
 }

include/prometheus/collectable.h

@@ -2,22 +2,20 @@
 
 #include <atomic>
 
-#include "metrics.pb.h"
-
+#include "prometheus/client_metric.h"
 #include "prometheus/gauge.h"
 #include "prometheus/metric.h"
 
 namespace prometheus {
-class Counter : Metric {
+class Counter {
  public:
-  static const io::prometheus::client::MetricType metric_type =
-      io::prometheus::client::COUNTER;
+  static const MetricType metric_type = MetricType::Counter;
 
   void Increment();
   void Increment(double);
   double Value() const;
 
-  io::prometheus::client::Metric Collect();
+  ClientMetric Collect();
 
  private:
   Gauge gauge_;

include/prometheus/counter.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <algorithm>
+#include <cassert>
 #include <functional>
 #include <map>
 #include <memory>
@@ -15,6 +16,7 @@
 #include "gauge_builder.h"
 #include "histogram_builder.h"
 #include "metric.h"
+#include "metric_family.h"
 
 namespace prometheus {
 
@@ -32,7 +34,7 @@ class Family : public Collectable {
   void Remove(T* metric);
 
   // Collectable
-  std::vector<io::prometheus::client::MetricFamily> Collect() override;
+  std::vector<MetricFamily> Collect() override;
 
  private:
   std::unordered_map<std::size_t, std::unique_ptr<T>> metrics_;
@@ -44,7 +46,7 @@ class Family : public Collectable {
   const std::map<std::string, std::string> constant_labels_;
   std::mutex mutex_;
 
-  io::prometheus::client::Metric CollectMetric(std::size_t hash, T* metric);
+  ClientMetric CollectMetric(std::size_t hash, T* metric);
 
   static std::size_t hash_labels(
       const std::map<std::string, std::string>& labels);
@@ -116,27 +118,27 @@ void Family<T>::Remove(T* metric) {
 }
 
 template <typename T>
-std::vector<io::prometheus::client::MetricFamily> Family<T>::Collect() {
+std::vector<MetricFamily> Family<T>::Collect() {
   std::lock_guard<std::mutex> lock{mutex_};
-  auto family = io::prometheus::client::MetricFamily{};
-  family.set_name(name_);
-  family.set_help(help_);
-  family.set_type(T::metric_type);
+  auto family = MetricFamily{};
+  family.name = name_;
+  family.help = help_;
+  family.type = T::metric_type;
   for (const auto& m : metrics_) {
-    *family.add_metric() = std::move(CollectMetric(m.first, m.second.get()));
+    family.metric.push_back(std::move(CollectMetric(m.first, m.second.get())));
   }
   return {family};
 }
 
 template <typename T>
-io::prometheus::client::Metric Family<T>::CollectMetric(std::size_t hash,
-                                                        T* metric) {
+ClientMetric Family<T>::CollectMetric(std::size_t hash, T* metric) {
   auto collected = metric->Collect();
   auto add_label =
       [&collected](const std::pair<std::string, std::string>& label_pair) {
-        auto pair = collected.add_label();
-        pair->set_name(label_pair.first);
-        pair->set_value(label_pair.second);
+        auto label = ClientMetric::Label{};
+        label.name = label_pair.first;
+        label.value = label_pair.second;
+        collected.label.push_back(std::move(label));
       };
   std::for_each(constant_labels_.cbegin(), constant_labels_.cend(), add_label);
   const auto& metric_labels = labels_.at(hash);