gracefully handle errors when writing cache log (#391)

* gracefully handle errors when writing cache log

* changelog

* fix log message

1 files changed, 50 insertions, 29 deletions

diff --git a/src/zenserver/cache/structuredcachestore.cpp b/src/zenserver/cache/structuredcachestore.cpp
index a115839ce..1f284863d 100644
--- a/src/zenserver/cache/structuredcachestore.cpp
+++ b/src/zenserver/cache/structuredcachestore.cpp
@@ -286,43 +286,64 @@ ZenCacheStore::LogWorker()
 	std::vector<AccessLogItem> Items;
 	while (true)
 	{
-		m_LogQueueLock.WithExclusiveLock([this, &Items]() { Items.swap(m_LogQueue); });
-		for (const auto& Item : Items)
+		try
 		{
-			if (Item.Value.Value)
+			m_LogQueueLock.WithExclusiveLock([this, &Items]() { Items.swap(m_LogQueue); });
+			for (const auto& Item : Items)
 			{
-				const bool IsCbObject = Item.Value.Value.GetContentType() == ZenContentType::kCbObject;
-
-				const IoHash ObjectHash = IsCbObject ? IoHash::HashBuffer(Item.Value.Value.GetView()) : Item.Value.RawHash;
-				const size_t ObjectSize = IsCbObject ? Item.Value.Value.GetSize() : Item.Value.RawSize;
-
-				ZEN_LOG_INFO(LogCacheActivity,
-							 "{} [{}] {}/{}/{} -> {} {} {}",
-							 Item.Op,
-							 Item.Context,
-							 Item.Namespace,
-							 Item.Bucket,
-							 Item.HashKey,
-							 ObjectHash,
-							 ObjectSize,
-							 ToString(Item.Value.Value.GetContentType()))
+				if (Item.Value.Value)
+				{
+					const bool IsCbObject = Item.Value.Value.GetContentType() == ZenContentType::kCbObject;
+
+					try
+					{
+						const IoHash ObjectHash = IsCbObject ? IoHash::HashBuffer(Item.Value.Value.GetView()) : Item.Value.RawHash;
+						const size_t ObjectSize = IsCbObject ? Item.Value.Value.GetSize() : Item.Value.RawSize;
+
+						ZEN_LOG_INFO(LogCacheActivity,
+									 "{} [{}] {}/{}/{} -> {} {} {}",
+									 Item.Op,
+									 Item.Context,
+									 Item.Namespace,
+									 Item.Bucket,
+									 Item.HashKey,
+									 ObjectHash,
+									 ObjectSize,
+									 ToString(Item.Value.Value.GetContentType()))
+					}
+					catch (std::exception& Ex)
+					{
+						ZEN_LOG_INFO(LogCacheActivity,
+									 "{} [{}] {}/{}/{} failed: Reason: '{}'",
+									 Item.Op,
+									 Item.Context,
+									 Item.Namespace,
+									 Item.Bucket,
+									 Item.HashKey,
+									 Ex.what())
+					}
+				}
+				else
+				{
+					ZEN_LOG_INFO(LogCacheActivity, "{} [{}] {}/{}/{}", Item.Op, Item.Context, Item.Namespace, Item.Bucket, Item.HashKey);
+				}
 			}
-			else
+			if (!Items.empty())
 			{
-				ZEN_LOG_INFO(LogCacheActivity, "{} [{}] {}/{}/{}", Item.Op, Item.Context, Item.Namespace, Item.Bucket, Item.HashKey);
+				Items.resize(0);
+				continue;
 			}
+			if (m_ExitLogging)
+			{
+				break;
+			}
+			m_LogEvent.Wait();
+			m_LogEvent.Reset();
 		}
-		if (!Items.empty())
-		{
-			Items.resize(0);
-			continue;
-		}
-		if (m_ExitLogging)
+		catch (std::exception& Ex)
 		{
-			break;
+			ZEN_WARN("Log writer failed: '{}'", Ex.what());
 		}
-		m_LogEvent.Wait();
-		m_LogEvent.Reset();
 	}
 }