statsd metrics reporting (#496)

added support for reporting metrics via statsd style UDP messaging, which is supported by many monitoring solution providers

this change adds reporting only of three cache related metrics (hit/miss/put) but this should be extended to include more metrics after additional evaluation

1 files changed, 24 insertions, 4 deletions

diff --git a/src/zenserver/cache/structuredcachestore.cpp b/src/zenserver/cache/structuredcachestore.cpp
index 89123a70f..6fab14eee 100644
--- a/src/zenserver/cache/structuredcachestore.cpp
+++ b/src/zenserver/cache/structuredcachestore.cpp
@@ -16,6 +16,7 @@
 #include <zencore/timer.h>
 #include <zencore/trace.h>
 #include <zencore/workthreadpool.h>
+#include <zennet/statsdclient.h>
 #include <zenstore/scrubcontext.h>
 #include <zenutil/cache/cache.h>
 
@@ -663,7 +664,7 @@ ZenCacheStore::StorageSize() const
 }
 
 ZenCacheStore::CacheStoreStats
-ZenCacheStore::Stats()
+ZenCacheStore::Stats(bool IncludeNamespaceStats)
 {
 	ZenCacheStore::CacheStoreStats Result{.HitCount			  = m_HitCount,
 										  .MissCount		  = m_MissCount,
@@ -672,13 +673,32 @@ ZenCacheStore::Stats()
 										  .RejectedReadCount  = m_RejectedReadCount,
 										  .PutOps			  = m_PutOps.Snapshot(),
 										  .GetOps			  = m_GetOps.Snapshot()};
-	IterateNamespaces([&](std::string_view NamespaceName, ZenCacheNamespace& Store) {
-		Result.NamespaceStats.emplace_back(NamedNamespaceStats{.NamespaceName = std::string(NamespaceName), .Stats = Store.Stats()});
-	});
+
+	if (IncludeNamespaceStats)
+	{
+		IterateNamespaces([&](std::string_view NamespaceName, ZenCacheNamespace& Store) {
+			Result.NamespaceStats.emplace_back(NamedNamespaceStats{.NamespaceName = std::string(NamespaceName), .Stats = Store.Stats()});
+		});
+	}
+
 	return Result;
 }
 
 void
+ZenCacheStore::ReportMetrics(StatsDaemonClient& Statsd)
+{
+	const bool			   IncludeNamespaceStats = false;
+	const CacheStoreStats  Now					 = Stats(IncludeNamespaceStats);
+	const CacheStoreStats& Old					 = m_LastReportedMetrics;
+
+	Statsd.Meter("zen.cache_hits", Now.HitCount - Old.HitCount);
+	Statsd.Meter("zen.cache_misses", Now.MissCount - Old.MissCount);
+	Statsd.Meter("zen.cache_writes", Now.WriteCount - Old.WriteCount);
+
+	m_LastReportedMetrics = Now;
+}
+
+void
 ZenCacheStore::SetLoggingConfig(const Configuration::LogConfig& Loggingconfig)
 {
 	if (!Loggingconfig.EnableAccessLog && !Loggingconfig.EnableWriteLog)