Report RPC counts in server_info (#72)

src/rpc/Counters.cpp

@@ -0,0 +1,76 @@
+#include <rpc/Counters.h>
+
+namespace RPC
+{
+
+void
+Counters::initializeCounter(std::string const& method)
+{
+    std::shared_lock lk(mutex_);
+    if(methodInfo_.count(method) == 0)
+    {        
+        lk.unlock();
+        std::unique_lock ulk(mutex_);
+
+        // This calls the default constructor for methodInfo of the method.
+        methodInfo_[method];
+    }
+}
+
+void
+Counters::rpcErrored(std::string const& method)
+{
+    initializeCounter(method);
+
+    std::shared_lock lk(mutex_);
+    MethodInfo& counters = methodInfo_[method];
+    counters.started++;
+    counters.errored++;
+}
+
+void
+Counters::rpcComplete(
+    std::string const& method,
+    std::chrono::microseconds const& rpcDuration)
+{
+    initializeCounter(method);
+
+    std::shared_lock lk(mutex_);
+    MethodInfo& counters = methodInfo_[method];
+    counters.started++;
+    counters.finished++;
+    counters.duration += rpcDuration.count();
+}
+
+void
+Counters::rpcForwarded(std::string const& method)
+{
+    initializeCounter(method);
+
+    std::shared_lock lk(mutex_);
+    MethodInfo& counters = methodInfo_[method];
+    counters.forwarded++;
+}
+
+boost::json::object
+Counters::report()
+{
+    std::shared_lock lk(mutex_);
+    boost::json::object obj = {};
+    
+    for (auto const& [method, info] : methodInfo_)
+    {
+        boost::json::object counters = {};
+        counters["started"] = std::to_string(info.started);
+        counters["finished"] = std::to_string(info.finished);
+        counters["errored"] = std::to_string(info.errored);
+        counters["forwarded"] = std::to_string(info.forwarded);
+        counters["duration_us"] = std::to_string(info.duration);
+
+        obj[method] = std::move(counters);
+    }
+
+    return obj;
+}
+
+} // namespace RPC