Merge pull request #460 from asit-dhal/master

conditional logging

README.md

@@ -30,6 +30,7 @@ Very fast, header only, C++ logging library. [![Build Status](https://travis-ci.
 * Feature rich [call style](#usage-example) using the excellent [fmt](https://github.com/fmtlib/fmt) library.
 * Extremely fast asynchronous mode (optional) - using lockfree queues and other tricks to reach millions of calls/sec.
 * [Custom](https://github.com/gabime/spdlog/wiki/3.-Custom-formatting) formatting.
+* Conditional Logging
 * Multi/Single threaded loggers.
 * Various log targets:
     * Rotating log files.
@@ -91,6 +92,12 @@ int main(int, char*[])
         console->info("Welcome to spdlog!");
         console->error("Some error message with arg{}..", 1);
 
+	// Conditional logging example
+        auto i = 2;
+        console->info_if(i < 20, "Welcome to spdlog conditional logging!");
+        console->warn_if(i != 0, "an important message");
+        console->critical_if(i != 2, "a false warning which won't show up");
+
         // Formatting examples
         console->warn("Easy padding in numbers like {:08d}", 12);
         console->critical("Support for int: {0:d};  hex: {0:x};  oct: {0:o}; bin: {0:b}", 42);

example/example.cpp

@@ -6,6 +6,10 @@
 // spdlog usage example
 //
 //
+
+#define SPDLOG_TRACE_ON
+#define SPDLOG_DEBUG_ON
+
 #include "spdlog/spdlog.h"
 
 #include <iostream>
@@ -27,6 +31,12 @@ int main(int, char*[])
         console->info("Welcome to spdlog!");
         console->error("Some error message with arg{}..", 1);
 
+        // Conditional logging example
+        auto i = 2;
+        console->info_if(i < 20, "Welcome to spdlog conditional logging!");
+        console->warn_if(i != 0, "an important message");
+        console->critical_if(i != 2, "a false warning which won't show up");
+        
         // Formatting examples
         console->warn("Easy padding in numbers like {:08d}", 12);
         console->critical("Support for int: {0:d};  hex: {0:x};  oct: {0:o}; bin: {0:b}", 42);
@@ -34,6 +44,8 @@ int main(int, char*[])
         console->info("Positional args are {1} {0}..", "too", "supported");
         console->info("{:<30}", "left aligned");
 
+        SPDLOG_DEBUG_IF(console, true, "This is a debug log");
+
 
         spd::get("console")->info("loggers can be retrieved from a global registry using the spdlog::get(logger_name) function");
 
@@ -68,6 +80,8 @@ int main(int, char*[])
         // define SPDLOG_DEBUG_ON or SPDLOG_TRACE_ON
         SPDLOG_TRACE(console, "Enabled only #ifdef SPDLOG_TRACE_ON..{} ,{}", 1, 3.23);
         SPDLOG_DEBUG(console, "Enabled only #ifdef SPDLOG_DEBUG_ON.. {} ,{}", 1, 3.23);
+        SPDLOG_DEBUG_IF(console, true, "This is a debug log");
+
 
         // Asynchronous logging is very fast..
         // Just call spdlog::set_async_mode(q_size) and all created loggers from now on will be asynchronous..

include/spdlog/details/logger_impl.h

@@ -158,6 +158,79 @@ inline void spdlog::logger::critical(const char* fmt, const Arg1 &arg1, const Ar
     log(level::critical, fmt, arg1, args...);
 }
 
+template <typename... Args>
+inline void spdlog::logger::log_if(const bool flag, level::level_enum lvl, const char* msg)
+{
+    if (flag)
+    {
+        log(lvl, msg);
+    }
+}
+
+template<typename T>
+inline void spdlog::logger::log_if(const bool flag, level::level_enum lvl, const T& msg)
+{
+    if (flag)
+    {
+        log(lvl, msg);
+    }
+}
+
+template <typename Arg1, typename... Args>
+inline void spdlog::logger::trace_if(const bool flag, const char* fmt, const Arg1 &arg1, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::trace, fmt, arg1, args...);
+    }
+}
+
+template <typename Arg1, typename... Args>
+inline void spdlog::logger::debug_if(const bool flag, const char* fmt, const Arg1 &arg1, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::debug, fmt, arg1, args...);
+    }
+}
+
+template <typename Arg1, typename... Args>
+inline void spdlog::logger::info_if(const bool flag, const char* fmt, const Arg1 &arg1, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::info, fmt, arg1, args...);
+    }
+}
+
+template <typename Arg1, typename... Args>
+inline void spdlog::logger::warn_if(const bool flag, const char* fmt, const Arg1& arg1, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::warn, fmt, arg1, args...);
+    }
+}
+
+template <typename Arg1, typename... Args>
+inline void spdlog::logger::error_if(const bool flag, const char* fmt, const Arg1 &arg1, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::err, fmt, arg1, args...);
+    }
+}
+
+template <typename Arg1, typename... Args>
+inline void spdlog::logger::critical_if(const bool flag, const char* fmt, const Arg1 &arg1, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::critical, fmt, arg1, args...);
+    }
+}
+
+
 template<typename T>
 inline void spdlog::logger::trace(const T& msg)
 {
@@ -196,6 +269,61 @@ inline void spdlog::logger::critical(const T& msg)
     log(level::critical, msg);
 }
 
+template<typename T>
+inline void spdlog::logger::trace_if(const bool flag, const T& msg)
+{
+    if (flag)
+    {
+        log(level::trace, msg);
+    }
+}
+
+template<typename T>
+inline void spdlog::logger::debug_if(const bool flag, const T& msg)
+{
+    if (flag)
+    {
+        log(level::debug, msg);
+    }
+}
+
+template<typename T>
+inline void spdlog::logger::info_if(const bool flag, const T& msg)
+{
+    if (flag)
+    {
+        log(level::info, msg);
+    }
+}
+
+template<typename T>
+inline void spdlog::logger::warn_if(const bool flag, const T& msg)
+{
+    if (flag)
+    {
+        log(level::warn, msg);
+    }
+}
+
+template<typename T>
+inline void spdlog::logger::error_if(const bool flag, const T& msg)
+{
+    if (flag)
+    {
+        log(level::err, msg);
+    }
+}
+
+template<typename T>
+inline void spdlog::logger::critical_if(const bool flag, const T& msg)
+{
+    if (flag)
+    {
+        log(level::critical, msg);
+    }
+}
+
+
 #ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
 #include <codecvt>
 
@@ -252,6 +380,84 @@ inline void spdlog::logger::critical(const wchar_t* fmt, const Args&... args)
 {
     log(level::critical, fmt, args...);
 }
+
+//
+// conditional logging
+//
+
+template <typename... Args>
+inline void spdlog::logger::log_if(const bool flag, level::level_enum lvl, const wchar_t* msg)
+{
+    if (flag)
+    {
+        log(lvl, msg);
+    }
+}
+
+template <typename... Args>
+inline void spdlog::logger::log_if(const bool flag, level::level_enum lvl, const wchar_t* fmt, const Args&... args)
+{
+    if (flag)
+    {
+        log(lvl, fmt, args);
+    }
+}
+
+template <typename... Args>
+inline void spdlog::logger::trace_if(const bool flag, const wchar_t* fmt, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::trace, fmt, args...);
+    }
+}
+
+template <typename... Args>
+inline void spdlog::logger::debug_if(const bool flag, const wchar_t* fmt, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::debug, fmt, args...);
+    }
+}
+
+template <typename... Args>
+inline void spdlog::logger::info_if(const bool flag, const wchar_t* fmt, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::info, fmt, args...);
+    }
+}
+
+
+template <typename... Args>
+inline void spdlog::logger::warn_if(const bool flag, const wchar_t* fmt, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::warn, fmt, args...);
+    }
+}
+
+template <typename... Args>
+inline void spdlog::logger::error_if(const bool flag, const wchar_t* fmt, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::err, fmt, args...);
+    }
+}
+
+template <typename... Args>
+inline void spdlog::logger::critical_if(const bool flag, const wchar_t* fmt, const Args&... args)
+{
+    if (flag)
+    {
+        log(level::critical, fmt, args...);
+    }
+}
+
 #endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
 
 

include/spdlog/logger.h

@@ -43,6 +43,16 @@ public:
     template <typename Arg1, typename... Args> void warn(const char* fmt, const Arg1&, const Args&... args);
     template <typename Arg1, typename... Args> void error(const char* fmt, const Arg1&, const Args&... args);
     template <typename Arg1, typename... Args> void critical(const char* fmt, const Arg1&, const Args&... args);
+    
+    template <typename... Args> void log_if(const bool flag, level::level_enum lvl, const char* fmt, const Args&... args);
+    template <typename... Args> void log_if(const bool flag, level::level_enum lvl, const char* msg);
+    template <typename Arg1, typename... Args> void trace_if(const bool flag, const char* fmt, const Arg1&, const Args&... args);
+    template <typename Arg1, typename... Args> void debug_if(const bool flag, const char* fmt, const Arg1&, const Args&... args);
+    template <typename Arg1, typename... Args> void info_if(const bool flag, const char* fmt, const Arg1&, const Args&... args);
+    template <typename Arg1, typename... Args> void warn_if(const bool flag, const char* fmt, const Arg1&, const Args&... args);
+    template <typename Arg1, typename... Args> void error_if(const bool flag, const char* fmt, const Arg1&, const Args&... args);
+    template <typename Arg1, typename... Args> void critical_if(const bool flag, const char* fmt, const Arg1&, const Args&... args);
+
 #ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
     template <typename... Args> void log(level::level_enum lvl, const wchar_t* msg);
     template <typename... Args> void log(level::level_enum lvl, const wchar_t* fmt, const Args&... args);
@@ -52,6 +62,15 @@ public:
     template <typename... Args> void warn(const wchar_t* fmt, const Args&... args);
     template <typename... Args> void error(const wchar_t* fmt, const Args&... args);
     template <typename... Args> void critical(const wchar_t* fmt, const Args&... args);
+
+    template <typename... Args> void log_if(const bool flag, level::level_enum lvl, const wchar_t* msg);
+    template <typename... Args> void log_if(const bool flag, level::level_enum lvl, const wchar_t* fmt, const Args&... args);
+    template <typename... Args> void trace_if(const bool flag, const wchar_t* fmt, const Args&... args);
+    template <typename... Args> void debug_if(const bool flag, const wchar_t* fmt, const Args&... args);
+    template <typename... Args> void info_if(const bool flag, const wchar_t* fmt, const Args&... args);
+    template <typename... Args> void warn_if(const bool flag, const wchar_t* fmt, const Args&... args);
+    template <typename... Args> void error_if(const bool flag, const wchar_t* fmt, const Args&... args);
+    template <typename... Args> void critical_if(const bool flag, const wchar_t* fmt, const Args&... args);
 #endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
 
     template <typename T> void log(level::level_enum lvl, const T&);
@@ -62,6 +81,14 @@ public:
     template <typename T> void error(const T&);
     template <typename T> void critical(const T&);
 
+    template <typename T> void log_if(const bool flag, level::level_enum lvl, const T&);
+    template <typename T> void trace_if(const bool flag, const T&);
+    template <typename T> void debug_if(const bool flag, const T&);
+    template <typename T> void info_if(const bool flag, const T&);
+    template <typename T> void warn_if(const bool flag, const T&);
+    template <typename T> void error_if(const bool flag, const T&);
+    template <typename T> void critical_if(const bool flag, const T&);
+
     bool should_log(level::level_enum) const;
     void set_level(level::level_enum);
     level::level_enum level() const;

include/spdlog/spdlog.h

@@ -162,23 +162,25 @@ void drop_all();
 // SPDLOG_TRACE(my_logger, "some trace message");
 // SPDLOG_TRACE(my_logger, "another trace message {} {}", 1, 2);
 // SPDLOG_DEBUG(my_logger, "some debug message {} {}", 3, 4);
+// SPDLOG_DEBUG_IF(my_logger, true, "some debug message {} {}", 3, 4);
 ///////////////////////////////////////////////////////////////////////////////
 
 #ifdef SPDLOG_TRACE_ON
 #define SPDLOG_STR_H(x) #x
 #define SPDLOG_STR_HELPER(x) SPDLOG_STR_H(x)
 #define SPDLOG_TRACE(logger, ...) logger->trace("[" __FILE__ " line #" SPDLOG_STR_HELPER(__LINE__) "] " __VA_ARGS__)
+#define SPDLOG_TRACE_IF(logger, flag, ...) logger->trace_if(flag, "[" __FILE__ " line #" SPDLOG_STR_HELPER(__LINE__) "] " __VA_ARGS__)
 #else
 #define SPDLOG_TRACE(logger, ...)
 #endif
 
 #ifdef SPDLOG_DEBUG_ON
 #define SPDLOG_DEBUG(logger, ...) logger->debug(__VA_ARGS__)
+#define SPDLOG_DEBUG_IF(logger, flag, ...) logger->debug_if(flag, __VA_ARGS__)
 #else
 #define SPDLOG_DEBUG(logger, ...)
 #endif
 
-
 }
 
 

tests/cond_logging.cpp

@@ -0,0 +1,148 @@
+
+#include "includes.h"
+
+template<class T>
+std::string conditional_log(const bool flag, const T& what, spdlog::level::level_enum logger_level)
+{
+    std::ostringstream oss;
+    auto oss_sink = std::make_shared<spdlog::sinks::ostream_sink_mt>(oss);
+
+    spdlog::logger oss_logger("oss", oss_sink);
+    oss_logger.set_level(logger_level);
+    oss_logger.set_pattern("%v");
+
+    switch (logger_level)
+    {
+    case spdlog::level::trace:
+        oss_logger.trace_if(flag, what);
+        break;
+    case spdlog::level::debug:
+        oss_logger.debug_if(flag, what);
+        break;
+    case spdlog::level::info:
+        oss_logger.info_if(flag, what);
+        break;
+    case spdlog::level::warn:
+        oss_logger.warn_if(flag, what);
+        break;
+    case spdlog::level::err:
+        oss_logger.error_if(flag, what);
+        break;
+    case spdlog::level::critical:
+        oss_logger.critical_if(flag, what);
+        break;
+    }
+ 
+    return oss.str().substr(0, oss.str().length() - spdlog::details::os::eol_size);
+}
+
+template <typename Arg1, typename... Args> 
+std::string conditional_log_varags(spdlog::level::level_enum logger_level, const bool flag, const char* fmt, const Arg1& arg1, const Args&... args)
+{
+    std::ostringstream oss;
+    auto oss_sink = std::make_shared<spdlog::sinks::ostream_sink_mt>(oss);
+
+    spdlog::logger oss_logger("oss", oss_sink);
+    oss_logger.set_level(logger_level);
+    oss_logger.set_pattern("%v");
+
+    switch (logger_level)
+    {
+    case spdlog::level::trace:
+        oss_logger.trace_if(flag, fmt, arg1, args...);
+        break;
+    case spdlog::level::debug:
+        oss_logger.debug_if(flag, fmt, arg1, args...);
+        break;
+    case spdlog::level::info:
+        oss_logger.info_if(flag, fmt, arg1, args...);
+        break;
+    case spdlog::level::warn:
+        oss_logger.warn_if(flag, fmt, arg1, args...);
+        break;
+    case spdlog::level::err:
+        oss_logger.error_if(flag, fmt, arg1, args...);
+        break;
+    case spdlog::level::critical:
+        oss_logger.critical_if(flag, fmt, arg1, args...);
+        break;
+    }
+
+    return oss.str().substr(0, oss.str().length() - spdlog::details::os::eol_size);
+}
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+
+template <typename Arg1, typename... Args>
+std::wstring conditional_log_varags(spdlog::level::level_enum logger_level, const bool flag, const wchar_t* fmt, const Arg1& arg1, const Args&... args)
+{
+    std::wstringstream oss;
+    auto oss_sink = std::make_shared<spdlog::sinks::ostream_sink_mt>(oss);
+
+    spdlog::logger oss_logger("oss", oss_sink);
+    oss_logger.set_level(logger_level);
+    oss_logger.set_pattern("%v");
+
+    switch (logger_level)
+    {
+    case spdlog::level::trace:
+        oss_logger.trace_if(flag, fmt, arg1, args...);
+        break;
+    case spdlog::level::debug:
+        oss_logger.debug_if(flag, fmt, arg1, args...);
+        break;
+    case spdlog::level::info:
+        oss_logger.info_if(flag, fmt, arg1, args...);
+        break;
+    case spdlog::level::warn:
+        oss_logger.warn_if(flag, fmt, arg1, args...);
+        break;
+    case spdlog::level::err:
+        oss_logger.error_if(flag, fmt, arg1, args...);
+        break;
+    case spdlog::level::critical:
+        oss_logger.critical_if(flag, fmt, arg1, args...);
+        break;
+    }
+
+    return oss.str().substr(0, oss.str().length() - spdlog::details::os::eol_size);
+}
+
+#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
+
+TEST_CASE("conditional_trace_simple", "[conditional_trace_simple]")
+{
+    //const char
+    for (auto i = 0; i < 2; i++)
+    {
+        REQUIRE(conditional_log((i % 2 == 0), "Hello", spdlog::level::trace) == ( i % 2 == 0 ? "Hello" : ""));
+        REQUIRE(conditional_log((i % 2 == 0), "Hello", spdlog::level::debug) == (i % 2 == 0 ? "Hello" : ""));
+        REQUIRE(conditional_log((i % 2 == 0), "Hello", spdlog::level::info) == (i % 2 == 0 ? "Hello" : ""));
+        REQUIRE(conditional_log((i % 2 == 0), "Hello", spdlog::level::warn) == (i % 2 == 0 ? "Hello" : ""));
+        REQUIRE(conditional_log((i % 2 == 0), "Hello", spdlog::level::err) == (i % 2 == 0 ? "Hello" : ""));
+        REQUIRE(conditional_log((i % 2 == 0), "Hello", spdlog::level::critical) == (i % 2 == 0 ? "Hello" : ""));
+    }
+}
+
+TEST_CASE("conditional_trace_varargs", "[conditional_trace_varargs]")
+{
+    //const char
+    for (auto i = 0; i < 2; i++)
+    {
+        REQUIRE(conditional_log_varags(spdlog::level::trace, (i % 2 == 0), "Hello {}", i) == (i % 2 == 0 ? "Hello " + std::to_string(i) : ""));
+        REQUIRE(conditional_log_varags(spdlog::level::debug, (i % 2 == 0), "Hello {}", i) == (i % 2 == 0 ? "Hello " + std::to_string(i) : ""));
+        REQUIRE(conditional_log_varags(spdlog::level::info, (i % 2 == 0), "Hello {}", i) == (i % 2 == 0 ? "Hello " + std::to_string(i) : ""));
+        REQUIRE(conditional_log_varags(spdlog::level::warn, (i % 2 == 0), "Hello {}", i) == (i % 2 == 0 ? "Hello " + std::to_string(i) : ""));
+        REQUIRE(conditional_log_varags(spdlog::level::err, (i % 2 == 0), "Hello {}", i) == (i % 2 == 0 ? "Hello " + std::to_string(i) : ""));
+        REQUIRE(conditional_log_varags(spdlog::level::critical, (i % 2 == 0), "Hello {}", i) == (i % 2 == 0 ? "Hello " + std::to_string(i) : ""));
+
+#ifdef SPDLOG_WCHAR_TO_UTF8_SUPPORT
+        REQUIRE(conditional_log_varags(spdlog::level::trace, (i % 2 == 0), L"Hello {}", i) == (i % 2 == 0 ? L"Hello " + std::to_wstring(i) : L""));
+        REQUIRE(conditional_log_varags(spdlog::level::debug, (i % 2 == 0), L"Hello {}", i) == (i % 2 == 0 ? L"Hello " + std::to_wstring(i) : L""));
+        REQUIRE(conditional_log_varags(spdlog::level::info, (i % 2 == 0), L"Hello {}", i) == (i % 2 == 0 ? L"Hello " + std::to_wstring(i) : L""));
+        REQUIRE(conditional_log_varags(spdlog::level::warn, (i % 2 == 0), L"Hello {}", i) == (i % 2 == 0 ? L"Hello " + std::to_wstring(i) : L""));
+        REQUIRE(conditional_log_varags(spdlog::level::err, (i % 2 == 0), L"Hello {}", i) == (i % 2 == 0 ? L"Hello " + std::to_wstring(i) : L""));
+        REQUIRE(conditional_log_varags(spdlog::level::critical, (i % 2 == 0), L"Hello {}", i) == (i % 2 == 0 ? L"Hello " + std::to_wstring(i) : L""));
+#endif // SPDLOG_WCHAR_TO_UTF8_SUPPORT
+    }
+}

tests/tests.vcxproj

@@ -125,6 +125,7 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClCompile Include="cond_logging.cpp" />
     <ClCompile Include="errors.cpp" />
     <ClCompile Include="file_helper.cpp" />
     <ClCompile Include="file_log.cpp" />

tests/tests.vcxproj.filters

@@ -36,6 +36,9 @@
     <ClCompile Include="errors.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="cond_logging.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="includes.h">