add `flush` command and more gc status info (#483)

- Feature: New endpoint `/admin/flush ` to flush all storage - CAS, Cache and ProjectStore
- Feature: New command `zen flush` to flush all storage - CAS, Cache and ProjectStore
- Improved: Command `zen gc-status` now gives details about storage, when last GC occured, how long until next GC etc
- Changed: Cache access and write log are disabled by default

1 files changed, 56 insertions, 9 deletions

diff --git a/src/zenstore/include/zenstore/gc.h b/src/zenstore/include/zenstore/gc.h
index 2e52218f8..aaa156ebf 100644
--- a/src/zenstore/include/zenstore/gc.h
+++ b/src/zenstore/include/zenstore/gc.h
@@ -7,6 +7,10 @@
 #include <zenstore/caslog.h>
 #include <zenstore/scrubcontext.h>
 
+ZEN_THIRD_PARTY_INCLUDES_START
+#include <fmt/format.h>
+ZEN_THIRD_PARTY_INCLUDES_END
+
 #include <atomic>
 #include <chrono>
 #include <condition_variable>
@@ -149,8 +153,8 @@ public:
 	void AddGcStorage(GcStorage* Contributor);
 	void RemoveGcStorage(GcStorage* Contributor);
 
-	void CollectGarbage(GcContext& GcCtx);
-	void ScrubStorage(ScrubContext& GcCtx);
+	GcStorageSize CollectGarbage(GcContext& GcCtx);
+	void		  ScrubStorage(ScrubContext& GcCtx);
 
 	GcStorageSize TotalStorageSize() const;
 
@@ -189,6 +193,29 @@ struct GcSchedulerConfig
 	std::chrono::seconds  LightweightInterval{};
 };
 
+struct GcSchedulerState
+{
+	GcSchedulerStatus Status;
+
+	GcSchedulerConfig Config;
+
+	bool				 AreDiskWritesBlocked = false;
+	bool				 HasDiskReserve		  = false;
+	uint64_t			 DiskSize			  = 0;
+	uint64_t			 DiskUsed			  = 0;
+	uint64_t			 DiskFree			  = 0;
+	GcClock::TimePoint	 LastFullGcTime{};
+	GcClock::TimePoint	 LastLightweightGcTime{};
+	std::chrono::seconds RemainingTimeUntilLightweightGc;
+	std::chrono::seconds RemainingTimeUntilFullGc;
+	uint64_t			 RemainingSpaceUntilFullGC = 0;
+
+	std::chrono::seconds LastFullGcDuration{};
+	GcStorageSize		 LastFullGCDiff;
+	std::chrono::seconds LastLightweightGcDuration{};
+	GcStorageSize		 LastLightweightGCDiff;
+};
+
 class DiskUsageWindow
 {
 public:
@@ -221,6 +248,7 @@ public:
 	void			  Initialize(const GcSchedulerConfig& Config);
 	void			  Shutdown();
 	GcSchedulerStatus Status() const { return static_cast<GcSchedulerStatus>(m_Status.load()); }
+	GcSchedulerState  GetState() const;
 
 	struct TriggerGcParams
 	{
@@ -253,15 +281,21 @@ private:
 	virtual bool	AreDiskWritesAllowed() const override { return !m_AreDiskWritesBlocked.load(); }
 	DiskSpace		CheckDiskSpace();
 
-	spdlog::logger&					  m_Log;
-	GcManager&						  m_GcManager;
-	GcSchedulerConfig				  m_Config;
-	GcClock::TimePoint				  m_LastGcTime{};
-	GcClock::TimePoint				  m_LastLightweightGcTime{};
-	GcClock::TimePoint				  m_LastGcExpireTime{};
+	spdlog::logger&	   m_Log;
+	GcManager&		   m_GcManager;
+	GcSchedulerConfig  m_Config;
+	GcClock::TimePoint m_LastGcTime{};
+	GcClock::TimePoint m_LastLightweightGcTime{};
+	GcClock::TimePoint m_LastGcExpireTime{};
+
+	std::chrono::seconds m_LastFullGcDuration{};
+	GcStorageSize		 m_LastFullGCDiff;
+	std::chrono::seconds m_LastLightweightGcDuration{};
+	GcStorageSize		 m_LastLightweightGCDiff;
+
 	std::atomic_uint32_t			  m_Status{};
 	std::thread						  m_GcThread;
-	std::mutex						  m_GcMutex;
+	mutable std::mutex				  m_GcMutex;
 	std::condition_variable			  m_GcSignal;
 	std::optional<TriggerGcParams>	  m_TriggerGcParams;
 	std::optional<TriggerScrubParams> m_TriggerScrubParams;
@@ -274,3 +308,16 @@ private:
 void gc_forcelink();
 
 }  // namespace zen
+
+template<>
+struct fmt::formatter<zen::GcClock::TimePoint> : formatter<string_view>
+{
+	template<typename FormatContext>
+	auto format(const zen::GcClock::TimePoint& TimePoint, FormatContext& ctx)
+	{
+		std::time_t Time = std::chrono::system_clock::to_time_t(TimePoint);
+		char		TimeString[std::size("yyyy-mm-ddThh:mm:ss")];
+		std::strftime(std::data(TimeString), std::size(TimeString), "%FT%T", std::localtime(&Time));
+		return fmt::format_to(ctx.out(), "{}", TimeString);
+	}
+};