logging: add -loglevelalways=1 option

This option tells the logging system to always include a "[cat:level]"
prefix, so [net] becomes [net:debug], LogInfo/LogPrint statements will have
an [all:info] prefix, and LogWarning and LogError logs will become
[all:warning] and [all:error]. This may be easier for automated parsing
of logs, particularly if additional prefixes such as thread or source
location are enabled.

Author: ajtowns

src/init/common.cpp

@@ -40,6 +40,7 @@ void AddLoggingArgs(ArgsManager& argsman)
 #endif
     argsman.AddArg("-logsourcelocations", strprintf("Prepend debug output with name of the originating source location (source file, line number and function name) (default: %u)", DEFAULT_LOGSOURCELOCATIONS), ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-logtimemicros", strprintf("Add microsecond precision to debug timestamps (default: %u)", DEFAULT_LOGTIMEMICROS), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::DEBUG_TEST);
+    argsman.AddArg("-loglevelalways", strprintf("Always prepend a category and level (default: %u)", DEFAULT_LOGLEVELALWAYS), ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-printtoconsole", "Send trace/debug info to console (default: 1 when no -daemon. To disable logging to file, set -nodebuglogfile)", ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
     argsman.AddArg("-shrinkdebugfile", "Shrink debug.log file on client startup (default: 1 when no -debug)", ArgsManager::ALLOW_ANY, OptionsCategory::DEBUG_TEST);
 }
@@ -55,6 +56,7 @@ void SetLoggingOptions(const ArgsManager& args)
     LogInstance().m_log_threadnames = args.GetBoolArg("-logthreadnames", DEFAULT_LOGTHREADNAMES);
 #endif
     LogInstance().m_log_sourcelocations = args.GetBoolArg("-logsourcelocations", DEFAULT_LOGSOURCELOCATIONS);
+    LogInstance().m_always_print_category_level = args.GetBoolArg("-loglevelalways", DEFAULT_LOGLEVELALWAYS);
 
     fLogIPs = args.GetBoolArg("-logips", DEFAULT_LOGIPS);
 }

src/logging.cpp

@@ -392,7 +392,7 @@ std::string BCLog::Logger::GetLogPrefix(BCLog::LogFlags category, BCLog::Level l
 {
     if (category == LogFlags::NONE) category = LogFlags::ALL;
 
-    const bool has_category{category != LogFlags::ALL};
+    const bool has_category{m_always_print_category_level || category != LogFlags::ALL};
 
     // If there is no category, Info is implied
     if (!has_category && level == Level::Info) return {};
@@ -402,7 +402,7 @@ std::string BCLog::Logger::GetLogPrefix(BCLog::LogFlags category, BCLog::Level l
         s += LogCategoryToStr(category);
     }
 
-    if (!has_category || level != Level::Debug) {
+    if (m_always_print_category_level || !has_category || level != Level::Debug) {
         // If there is a category, Debug is implied, so don't add the level
 
         // Only add separator if we have a category

src/logging.h

@@ -25,6 +25,7 @@ static const bool DEFAULT_LOGIPS        = false;
 static const bool DEFAULT_LOGTIMESTAMPS = true;
 static const bool DEFAULT_LOGTHREADNAMES = false;
 static const bool DEFAULT_LOGSOURCELOCATIONS = false;
+static constexpr bool DEFAULT_LOGLEVELALWAYS = false;
 extern const char * const DEFAULT_DEBUGLOGFILE;
 
 extern bool fLogIPs;
@@ -119,6 +120,7 @@ namespace BCLog {
         bool m_log_time_micros = DEFAULT_LOGTIMEMICROS;
         bool m_log_threadnames = DEFAULT_LOGTHREADNAMES;
         bool m_log_sourcelocations = DEFAULT_LOGSOURCELOCATIONS;
+        bool m_always_print_category_level = DEFAULT_LOGLEVELALWAYS;
 
         fs::path m_file_path;
         std::atomic<bool> m_reopen_file{false};