Use fmt for logging and allow to log to system daemon directly

CMakeLists.txt

@@ -36,6 +36,8 @@ include(CMakeDependentOption)
 option(BTOP_STATIC "Link btop statically" OFF)
 option(BTOP_LTO "Enable LTO" ON)
 option(BTOP_USE_MOLD "Use mold to link btop" OFF)
+option(BTOP_SYSLOG "Log with syslog instead of log file" OFF)
+option(BTOP_JOURNALD "Directly log to journald instead of log file" OFF)
 option(BTOP_PEDANTIC "Enable a bunch of additional warnings" OFF)
 option(BTOP_WERROR "Compile with warnings as errors" OFF)
 option(BTOP_GPU "Enable GPU support" ON)
@@ -60,6 +62,7 @@ add_executable(btop
   src/btop_config.cpp
   src/btop_draw.cpp
   src/btop_input.cpp
+  src/btop_log.cpp
   src/btop_menu.cpp
   src/btop_shared.cpp
   src/btop_theme.cpp
@@ -131,6 +134,7 @@ target_compile_definitions(btop PRIVATE
   _GLIBCXX_ASSERTIONS _LIBCPP_ENABLE_ASSERTIONS=1
   # Only has an effect with optimizations enabled
   $<$<NOT:$<CONFIG:Debug>>:_FORTIFY_SOURCE=2>
+  FMT_HEADER_ONLY
 )
 
 # Enable GPU support
@@ -180,6 +184,22 @@ set(THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads REQUIRED)
 target_link_libraries(btop PRIVATE Threads::Threads)
 
+# Logging
+if(BTOP_JOURNALD)
+  find_package(Systemd REQUIRED)
+  target_compile_definitions(btop PRIVATE HAVE_JOURNALD)
+  target_link_libraries(btop PRIVATE Systemd::Journald)
+  message(STATUS "Using journald as logging backend")
+elseif(BTOP_SYSLOG)
+  check_include_file_cxx("syslog.h" HAVE_SYSLOG)
+  if(HAVE_SYSLOG)
+    target_compile_definitions(btop PRIVATE HAVE_SYSLOG)
+    message(STATUS "Using syslog as logging backend")
+  endif()
+else()
+  message(STATUS "Using plain log file")
+endif()
+
 if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   target_link_libraries(btop PRIVATE $<LINK_LIBRARY:FRAMEWORK,CoreFoundation)
   target_link_libraries(btop PRIVATE $<LINK_LIBRARY:FRAMEWORK,IOKit)

Makefile

@@ -167,6 +167,13 @@ else
 	LTO := $(THREADS)
 endif
 
+#? Enable journald direct logging
+ifeq ($(ENABLE_JOURNALD),true)
+	override ADDFLAGS += $(shell echo "int main() {}" | $(CXX) -include "systemd/sd-journal.h" -lsystemd -o /dev/null -x c++ - >/dev/null 2>&1 && echo "-DHAVE_JOURNALD -lsystemd")
+else ifeq ($(ENABLE_SYSLOG),true)
+	override ADDFLAGS += $(strip $(shell echo "int main() {}" | $(CXX) -include "syslog.h" -o /dev/null -x c++ - >/dev/null 2>&1 && echo "-DHAVE_SYSLOG"))
+endif
+
 #? The Directories, Source, Includes, Objects and Binary
 SRCDIR		:= src
 INCDIRS		:= include $(wildcard lib/**/include)
@@ -183,7 +190,7 @@ override GOODFLAGS := $(foreach flag,$(TESTFLAGS),$(strip $(shell echo "int main
 override REQFLAGS   := -std=c++20
 WARNFLAGS			:= -Wall -Wextra -pedantic
 OPTFLAGS			:= -O2 -ftree-vectorize -flto=$(LTO)
-LDCXXFLAGS			:= -pthread -D_FORTIFY_SOURCE=2 -D_GLIBCXX_ASSERTIONS -D_FILE_OFFSET_BITS=64 $(GOODFLAGS) $(ADDFLAGS)
+LDCXXFLAGS			:= -pthread -DFMT_HEADER_ONLY -D_FORTIFY_SOURCE=2 -D_GLIBCXX_ASSERTIONS -D_FILE_OFFSET_BITS=64 $(GOODFLAGS) $(ADDFLAGS)
 override CXXFLAGS	+= $(REQFLAGS) $(LDCXXFLAGS) $(OPTFLAGS) $(WARNFLAGS)
 override LDFLAGS	+= $(LDCXXFLAGS) $(OPTFLAGS) $(WARNFLAGS)
 INC					:= $(foreach incdir,$(INCDIRS),-isystem $(incdir)) -I$(SRCDIR)

README.md

@@ -493,6 +493,8 @@ Also needs a UTF8 locale and a font that covers:
    | `-DBTOP_STATIC=<ON\|OFF>`       | Enables static linking (OFF by default)                                 |
    | `-DBTOP_LTO=<ON\|OFF>`          | Enables link time optimization (ON by default)                          |
    | `-DBTOP_USE_MOLD=<ON\|OFF>`     | Use mold to link btop (OFF by default)                                  |
+   | `-DBTOP_SYSLOG=<ON\|OFF>`       | Log to syslog instead of a log file (OFF by default)                    |
+   | `-DBTOP_JOURNALD=<ON\|OFF>`     | Log to journald instead of a log file (OFF by default)                  |
    | `-DBTOP_PEDANTIC=<ON\|OFF>`     | Compile with additional warnings (OFF by default)                       |
    | `-DBTOP_WERROR=<ON\|OFF>`       | Compile with warnings as errors (OFF by default)                        |
    | `-DBTOP_GPU=<ON\|OFF>`          | Enable GPU support (ON by default)                                      |
@@ -764,6 +766,7 @@ Also needs a UTF8 locale and a font that covers:
    | `-DBTOP_STATIC=<ON\|OFF>`       | Enables static linking (OFF by default)                                 |
    | `-DBTOP_LTO=<ON\|OFF>`          | Enables link time optimization (ON by default)                          |
    | `-DBTOP_USE_MOLD=<ON\|OFF>`     | Use mold to link btop (OFF by default)                                  |
+   | `-DBTOP_SYSLOG=<ON\|OFF>`       | Log to syslog instead of a log file (OFF by default)                    |
    | `-DBTOP_PEDANTIC=<ON\|OFF>`     | Compile with additional warnings (OFF by default)                       |
    | `-DBTOP_WERROR=<ON\|OFF>`       | Compile with warnings as errors (OFF by default)                        |
    | `-DCMAKE_INSTALL_PREFIX=<path>` | The installation prefix ('/usr/local' by default)                       |
@@ -1053,6 +1056,13 @@ optional arguments:
                         and screen draw functions and sets loglevel to DEBUG
 ```
 
+It's also possible to specify a log level using the `BTOP_LOG_LEVEL` environment variable.
+It takes the same values as the `log_level` configuation option + "DISABLED", being case insensitive.
+```bash
+BTOP_LOG_LEVEL=info btop
+```
+will launch btop with the info logging level.
+
 ## LICENSE
 
 [Apache License 2.0](LICENSE)

cmake/Modules/FindSystemd.cmake

@@ -0,0 +1,26 @@
+# SPDX-License-Identifier: Apache-2.0
+#
+# Find systemd
+#
+
+if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+  find_path(Systemd_INCLUDE_DIR NAMES systemd/sd-journal.h)
+  find_library(Systemd_LIBRARY NAMES systemd)
+
+  include(FindPackageHandleStandardArgs)
+  find_package_handle_standard_args(Systemd REQUIRED_VARS Systemd_LIBRARY Systemd_INCLUDE_DIR)
+
+  if(Systemd_FOUND AND NOT TARGET Systemd::Systemd)
+    add_library(Systemd::Systemd UNKNOWN IMPORTED)
+    set_target_properties(Systemd::Systemd PROPERTIES
+      IMPORTED_LOCATION "${Systemd_LIBRARY}"
+    )
+  endif()
+
+  if(Systemd_FOUND AND NOT TARGET Systemd::Journald)
+    add_library(Systemd::Journald ALIAS Systemd::Systemd)
+  endif()
+
+  mark_as_advanced(Systemd_INCLUDE_DIR Systemd_LIBRARY)
+endif()
+

src/btop.cpp

@@ -43,13 +43,14 @@ tab-size = 4
 	#include <semaphore>
 #endif
 
-#include "btop_shared.hpp"
-#include "btop_tools.hpp"
 #include "btop_config.hpp"
-#include "btop_input.hpp"
-#include "btop_theme.hpp"
 #include "btop_draw.hpp"
+#include "btop_input.hpp"
+#include "btop_log.hpp"
 #include "btop_menu.hpp"
+#include "btop_shared.hpp"
+#include "btop_theme.hpp"
+#include "btop_tools.hpp"
 
 using std::atomic;
 using std::cout;
@@ -283,10 +284,10 @@ void clean_quit(int sig) {
 
 	if (not Global::exit_error_msg.empty()) {
 		sig = 1;
-		Logger::error(Global::exit_error_msg);
+		Logger::error("{}", Global::exit_error_msg);
 		fmt::println(std::cerr, "{}ERROR: {}{}{}", Global::fg_red, Global::fg_white, Global::exit_error_msg, Fx::reset);
 	}
-	Logger::info("Quitting! Runtime: " + sec_to_dhms(time_s() - Global::start_time));
+	Logger::info("Quitting! Runtime: {}", sec_to_dhms(time_s() - Global::start_time));
 
 	const auto excode = (sig != -1 ? sig : 0);
 
@@ -846,7 +847,9 @@ int main(int argc, char **argv) {
 		}
 		else {
 			Config::conf_file = Config::conf_dir / "btop.conf";
+#if !(defined(HAVE_JOURNALD) || defined(HAVE_SYSLOG))
 			Logger::logfile = Config::conf_dir / "btop.log";
+#endif
 			Theme::user_theme_dir = Config::conf_dir / "themes";
 			if (not fs::exists(Theme::user_theme_dir) and not fs::create_directory(Theme::user_theme_dir, ec)) Theme::user_theme_dir.clear();
 		}
@@ -879,27 +882,40 @@ int main(int argc, char **argv) {
 	}
 
 	//? Config init
-	{	vector<string> load_warnings;
+	{
+		vector<string> load_warnings;
 		Config::load(Config::conf_file, load_warnings);
 
 		if (Config::current_boxes.empty()) Config::check_boxes(Config::getS("shown_boxes"));
 		Config::set("lowcolor", (Global::arg_low_color ? true : not Config::getB("truecolor")));
 
+		std::string log_level_env {};
+		{
+			char* log_env = std::getenv("BTOP_LOG_LEVEL");
+			if (log_env != nullptr) {
+				log_level_env = Tools::str_to_upper(log_env);
+			}
+		}
 		if (Global::debug) {
 			Logger::set("DEBUG");
 			Logger::debug("Starting in DEBUG mode!");
 		}
-		else Logger::set(Config::getS("log_level"));
-
-		Logger::info("Logger set to " + (Global::debug ? "DEBUG" : Config::getS("log_level")));
+		else if (v_contains(Logger::log_levels, log_level_env)) {
+			Logger::set(log_level_env);
+			Logger::info("Log level set to {}", log_level_env);
+		}
+		else {
+			Logger::set(Config::getS("log_level"));
+			Logger::info("Log level set to {}", Config::getS("log_level"));
+		}
 
-		for (const auto& err_str : load_warnings) Logger::warning(err_str);
+		for (const auto& err_str : load_warnings) Logger::warning("{}", err_str);
 	}
 
 	//? Try to find and set a UTF-8 locale
 	if (std::setlocale(LC_ALL, "") != nullptr and not s_contains((string)std::setlocale(LC_ALL, ""), ";")
 	and str_to_upper(s_replace((string)std::setlocale(LC_ALL, ""), "-", "")).ends_with("UTF8")) {
-		Logger::debug("Using locale " + (string)std::setlocale(LC_ALL, ""));
+		Logger::debug("Using locale {}", std::setlocale(LC_ALL, ""));
 	}
 	else {
 		string found;
@@ -909,7 +925,7 @@ int main(int argc, char **argv) {
 				found = std::getenv(loc_env);
 				if (std::setlocale(LC_ALL, found.c_str()) == nullptr) {
 					set_failure = true;
-					Logger::warning("Failed to set locale " + found + " continuing anyway.");
+					Logger::warning("Failed to set locale {} continuing anyway.", found);
 				}
 			}
 		}
@@ -942,7 +958,7 @@ int main(int argc, char **argv) {
 				Logger::warning("No UTF-8 locale detected! Some symbols might not display correctly.");
 			}
 			else if (std::setlocale(LC_ALL, string(cur_locale + ".UTF-8").c_str()) != nullptr) {
-				Logger::debug("Setting LC_ALL=" + cur_locale + ".UTF-8");
+				Logger::debug("Setting LC_ALL={}.UTF-8", cur_locale);
 			}
 			else if(std::setlocale(LC_ALL, "en_US.UTF-8") != nullptr) {
 				Logger::debug("Setting LC_ALL=en_US.UTF-8");
@@ -960,7 +976,7 @@ int main(int argc, char **argv) {
 		}
 	#endif
 		else if (not set_failure)
-			Logger::debug("Setting LC_ALL=" + found);
+			Logger::debug("Setting LC_ALL={}", found);
 	}
 
 	//? Initialize terminal and set options
@@ -969,7 +985,7 @@ int main(int argc, char **argv) {
 		clean_quit(1);
 	}
 
-	if (Term::current_tty != "unknown") Logger::info("Running on " + Term::current_tty);
+	if (Term::current_tty != "unknown") Logger::info("Running on {}", Term::current_tty);
 	if (not Global::arg_tty and Config::getB("force_tty")) {
 		Config::set("tty_mode", true);
 		Logger::info("Forcing tty mode: setting 16 color mode and using tty friendly graph symbols");

src/btop_config.cpp

@@ -25,6 +25,7 @@ tab-size = 4
 #include <fmt/core.h>
 
 #include "btop_config.hpp"
+#include "btop_log.hpp"
 #include "btop_shared.hpp"
 #include "btop_tools.hpp"
 

src/btop_draw.cpp

@@ -23,13 +23,14 @@ tab-size = 4
 #include <stdexcept>
 #include <string>
 
-#include "btop_draw.hpp"
 #include "btop_config.hpp"
-#include "btop_theme.hpp"
-#include "btop_shared.hpp"
-#include "btop_tools.hpp"
+#include "btop_draw.hpp"
 #include "btop_input.hpp"
+#include "btop_log.hpp"
 #include "btop_menu.hpp"
+#include "btop_shared.hpp"
+#include "btop_theme.hpp"
+#include "btop_tools.hpp"
 
 
 using std::array;
@@ -225,7 +226,7 @@ namespace Draw {
 				c_upos = ulen(first);
 			}
 			catch (const std::exception& e) {
-				Logger::error("In TextEdit::operator() : " + string{e.what()});
+				Logger::error("In TextEdit::operator() : {}", e.what());
 				return "";
 			}
 		}
@@ -294,7 +295,7 @@ namespace Draw {
 	}
 
 	bool update_clock(bool force) {
-		const auto& clock_format = Config::getS("clock_format");
+		const std::string_view clock_format = Config::getS("clock_format");
 		if (not Cpu::shown or clock_format.empty()) {
 			if (clock_format.empty() and not Global::clock.empty()) Global::clock.clear();
 			return false;