spdlog implementation hiding (#498)

this change aims to hide logging internals from client code, in order to make it easier to extend and take more control over the logging process in the future. 

As a bonus side effect, the generated code is much tighter (net delta around 2.5% on the resulting executable which includes lots of thirdparty code) and should take less time to compile and link.

Client usage via macros is pretty much unchanged. The main exposure client code had to spdlog internals before was the use of custom loggers per subsystem, where it would be common to have `spdlog::logger` references to keep a reference to a logger within a class. This is now replaced by `zen::LoggerRef` which currently simply encapsulates an actual `spdlog::logger` instance, but this is intended to be an implementation detail which will change in the future.

The way the change works is that we now handle any formatting of log messages in the zencore logging subsystem instead of relying on `spdlog` to manage this. We use the `fmt` library to do the formatting which means the client usage is identical to using `spdlog`. The formatted message is then forwarded onto any sinks etc which are still implememted via `spdlog`.

3 files changed, 16 insertions, 21 deletions

diff --git a/src/zenserver/upstream/jupiter.h b/src/zenserver/upstream/jupiter.h
index ca84905d2..467f28501 100644
--- a/src/zenserver/upstream/jupiter.h
+++ b/src/zenserver/upstream/jupiter.h
@@ -131,15 +131,15 @@ public:
 	CloudCacheClient& Client() { return *m_CacheClient; };
 
 private:
-	inline spdlog::logger& Log() { return m_Log; }
-	cpr::Session&		   GetSession();
-	CloudCacheAccessToken  GetAccessToken(bool RefreshToken = false);
+	inline LoggerRef	  Log() { return m_Log; }
+	cpr::Session&		  GetSession();
+	CloudCacheAccessToken GetAccessToken(bool RefreshToken = false);
 
 	CloudCacheResult CacheTypeExists(std::string_view Namespace, std::string_view TypeId, const IoHash& Key);
 
 	CloudCacheExistsResult CacheTypeExists(std::string_view Namespace, std::string_view TypeId, const std::set<IoHash>& Keys);
 
-	spdlog::logger&					m_Log;
+	LoggerRef						m_Log;
 	RefPtr<CloudCacheClient>		m_CacheClient;
 	detail::CloudCacheSessionState* m_SessionState;
 };
@@ -195,10 +195,10 @@ public:
 	std::string_view	  ComputeCluster() const { return m_ComputeCluster; }
 	std::string_view	  ServiceUrl() const { return m_ServiceUrl; }
 
-	spdlog::logger& Logger() { return m_Log; }
+	LoggerRef Logger() { return m_Log; }
 
 private:
-	spdlog::logger&							 m_Log;
+	LoggerRef								 m_Log;
 	std::string								 m_ServiceUrl;
 	std::string								 m_DefaultDdcNamespace;
 	std::string								 m_DefaultBlobStoreNamespace;
diff --git a/src/zenserver/upstream/upstreamcache.cpp b/src/zenserver/upstream/upstreamcache.cpp
index 5f711d0bc..8e00f86b0 100644
--- a/src/zenserver/upstream/upstreamcache.cpp
+++ b/src/zenserver/upstream/upstreamcache.cpp
@@ -29,7 +29,6 @@
 #include <atomic>
 #include <shared_mutex>
 #include <thread>
-#include <unordered_map>
 
 namespace zen {
 
@@ -753,10 +752,10 @@ namespace detail {
 			return {.Bytes = TotalBytes, .ElapsedSeconds = TotalElapsedSeconds, .Success = true};
 		}
 
-		spdlog::logger& Log() { return m_Log; }
+		LoggerRef Log() { return m_Log; }
 
 		AuthMgr&				 m_AuthMgr;
-		spdlog::logger&			 m_Log;
+		LoggerRef				 m_Log;
 		UpstreamEndpointInfo	 m_Info;
 		UpstreamStatus			 m_Status;
 		UpstreamEndpointStats	 m_Stats;
@@ -1460,9 +1459,9 @@ namespace detail {
 			return m_Endpoints.front();
 		}
 
-		spdlog::logger& Log() { return m_Log; }
+		LoggerRef Log() { return m_Log; }
 
-		spdlog::logger&					 m_Log;
+		LoggerRef						 m_Log;
 		UpstreamEndpointInfo			 m_Info;
 		UpstreamStatus					 m_Status;
 		UpstreamEndpointStats			 m_Stats;
@@ -2078,7 +2077,7 @@ private:
 		}
 	}
 
-	spdlog::logger& Log() { return m_Log; }
+	LoggerRef Log() { return m_Log; }
 
 	using UpstreamQueue = BlockingQueue<UpstreamCacheRecord>;
 
@@ -2103,7 +2102,7 @@ private:
 		}
 	};
 
-	spdlog::logger&								   m_Log;
+	LoggerRef									   m_Log;
 	UpstreamCacheOptions						   m_Options;
 	ZenCacheStore&								   m_CacheStore;
 	CidStore&									   m_CidStore;
diff --git a/src/zenserver/upstream/zen.h b/src/zenserver/upstream/zen.h
index bfba8fa98..c1e4fbd0f 100644
--- a/src/zenserver/upstream/zen.h
+++ b/src/zenserver/upstream/zen.h
@@ -20,10 +20,6 @@ ZEN_THIRD_PARTY_INCLUDES_END
 
 struct ZenCacheValue;
 
-namespace spdlog {
-class logger;
-}
-
 namespace zen {
 
 class CbObjectWriter;
@@ -85,9 +81,9 @@ public:
 	ZenCacheResult InvokeRpc(const CbPackage& Package);
 
 private:
-	inline spdlog::logger& Log() { return m_Log; }
+	inline LoggerRef Log() { return m_Log; }
 
-	spdlog::logger&				  m_Log;
+	LoggerRef					  m_Log;
 	Ref<ZenStructuredCacheClient> m_Client;
 	detail::ZenCacheSessionState* m_SessionState;
 };
@@ -105,10 +101,10 @@ public:
 
 	std::string_view ServiceUrl() const { return m_ServiceUrl; }
 
-	inline spdlog::logger& Log() { return m_Log; }
+	inline LoggerRef Log() { return m_Log; }
 
 private:
-	spdlog::logger&			  m_Log;
+	LoggerRef				  m_Log;
 	std::string				  m_ServiceUrl;
 	std::chrono::milliseconds m_ConnectTimeout;
 	std::chrono::milliseconds m_Timeout;