中文版本 | English Edition
Log4cpp is library of C++ classes. It is modeled after the Log4j Java library
Features:
- Configure through JSON files, and control its behavior without modifying the code
- Logs can be output to STDOUT, STDERR
- The log can be output to the specified file
- Can output logs to TCP client
- Can output logs to UDP client
- Singleton mode
- Thread safety
- C++ compiler that supports C++17 and above
- CMake 3.11 and above
- Boost >= 1.75
Warning: Due to a series of bugs in the MSVC compiler, this project no longer supports MSVC. Any errors on the MSVC platform will no longer be fixed. It is recommended to use MingW64
include(FetchContent)
FetchContent_Declare(log4cpp GIT_REPOSITORY https://github.com/SandroDickens/log4cpp.git GIT_TAG v3.0.5)
FetchContent_MakeAvailable(log4cpp)
target_link_libraries(${YOUR_TARGET_NAME} log4cpp){
"layout_pattern": "${yyyy}-${MM}-${dd} ${HH}:${mm}:${ss}:${ms} [${8TH}] [${L}] -- ${W}"
}Description:
${yy}: A two digit representation of a year. e.g. 99 or 03${yyyy}: A full numeric representation of a year, at least 4 digits, with - for years BCE. e.g. -0055, 0787, 1999, 2003, 10191${M}: Numeric representation of a month, without leading zeros. 1 through 12${MM}: Numeric representation of a month, with leading zeros. 01 through 12${MMM}: A short textual representation of a month, three letters. Jan through Dec${d}: Day of the month without leading zeros. 1 to 31${dd}: Day of the month, 2 digits with leading zeros. 01 to 31${h}: 12-hour format of an hour without leading zeros, with Uppercase Ante meridiem and Post meridiem, 0 through 12${hh}: 12-hour format of an hour with leading zeros, with Uppercase Ante meridiem and Post meridiem, 00 through 12${H}: 24-hour format of an hour without leading zeros. 0 through 23${HH}: 24-hour format of an hour with leading zeros. 00 through 23${m}: Minutes without leading zeros. 1 to 59${mm}: Minutes with leading zeros. 01 to 59${s}: Seconds without leading zeros. 1 to 59${ss}: Seconds with leading zeros. 01 to 59${ms}: Milliseconds with leading zeros. 001 to 999${<n>TN}: Thread name. e.g.${8TN}.<n>is the name length, align left, default is 16, max width is 16. If the name is empty, use "T+thread id" instead. e.g. "main"${<n>TH}: Thread id, e.g.${8TH}.<n>is the digit width, left padding with 0, default is 8, max width is 8. e.g. "T12345"${L}: Log level, Value range: FATAL, ERROR, WARN, INFO, DEBUG, TRACE${W}: Log message, e.g. hello world!
Warning: Some systems cannot set thread names, and only multiple threads can be distinguished by thread ID
There are four types of appender: Console appender(console_appender), File appender(file_appender), TCP appender(
tcp_appender), UDP appender(udp_appender)
A simple configuration file example:
{
"appenders": {
"console_appender": {
"out_stream": "stdout"
},
"file_appender": {
"file_path": "log/log4cpp.log"
},
"tcp_appender": {
"local_addr": "0.0.0.0",
"port": 9443
},
"udp_appender": {
"local_addr": "0.0.0.0",
"port": 9443
}
}
}The function of the console appender is to output logs to STDOUT or STDERR. Typical configuration is as follows:
{
"appenders": {
"console_appender": {
"out_stream": "stdout"
}
}
}Description:
out_stream: output stream, can be stdout or stderr
The function of the file appender is to output logs to a specified file. Typical configuration is as follows:
{
"appenders": {
"file_appender": {
"file_path": "log/log4cpp.log"
}
}
}Description:
file_path: output file name
The TCP appender will start a TCP server inside, accept TCP connections, and output logs to the connected client, which is used to output logs to remote devices. The typical configuration is as follows:
{
"appenders": {
"tcp_appender": {
"local_addr": "0.0.0.0",
"port": 9443
}
}
}Description:
local_addr: Listening address. For example, "0.0.0.0", "::", "127.0.0.1", "::1"port: Listening port
Note: If there are multiple TCP clients, it will be convenient for all clients to send logs one by one
Note: Logs are transmitted in plain text, pay attention to privacy and security issues. Encrypted transmission will not be supported in the future. If encryption is required, it is recommended to encrypt the logs before passing them to log4cpp
A UDP server will be started inside the UDP log appender to export logs to the connected client, which is used to export logs to remote devices
Unlike the TCP protocol, UDP is connectionless. Please note:
- UDP is connectionless and cannot guarantee the integrity of the log
- The client needs to actively send a "hello" message so that the server can obtain the client address and send logs
- When the client exits, it needs to send a "bye" message so that the server can clean up the client address. Otherwise, the client address will be retained until it is cleaned up due to log sending failure or program exit
The typical configuration is as follows:
{
"appenders": {
"udp_appender": {
"local_addr": "0.0.0.0",
"port": 9443
}
}
}Description:
local_addr: listening address. For example, "0.0.0.0", "::", "127.0.0.1", "::1"port: listening port
There are two types of Layouts:
- Named layout: configuration name
layouts - Root layout: configuration name
root_layout
If there is no layout with a specified name when log4cpp::layout_manager::get_layout, the root_layout is returned
Note: The named layout is optional, but the root layout must be present
Named layouts are an array, and each layout configuration includes:
name: layout name, used to get layouts, unique, cannot berootlog_level: log level, only logs greater than or equal to this level will be outputappenders: appender, Must be configured inappendersbefore it can be referenced here. Appender can beconsole_appender,file_appender,tcp_appender,udp_appender
Root layout is an object, only log_level and appenders, no name, internal implementation of name is root
{
"layouts": [
{
"name": "console_layout",
"log_level": "INFO",
"appenders": [
"console_appender",
"tcp_appender",
"udp_appender"
]
},
{
"name": "file_layout",
"log_level": "WARN",
"appenders": [
"file_appender"
]
}
],
"root_layout": {
"log_level": "INFO",
"appenders": [
"console_appender",
"file_appender",
"tcp_appender",
"udp_appender"
]
}
}There are two ways to load configuration file:
- If
log4cpp.jsonexists in the current path, this configuration file will be automatically loaded - If the configuration file is not in the current path, or the file name is not
log4cpp.json, Need to load the configuration file manually
log4cpp::layout_manager::load_config("/config_path/log4cpp.json");First, you need to import the header file:
#include "log4cpp.hpp"Then, get the layout instance
Get the layout by name. If the specified layout does not exist, return root_layout
std::shared_ptr<log4cpp::layout> log = log4cpp::layout_manager::get_layout("layout_name");Write log message
After getting the layout, you can use the following method to output the log:
void trace(const char *__restrict fmt, ...);
void info(const char *__restrict fmt, ...);
void debug(const char *__restrict fmt, ...);
void warn(const char *__restrict fmt, ...);
void error(const char *__restrict fmt, ...);
void fatal(const char *__restrict fmt, ...);The above method calls the following method internally, or you can call the following method directly:
void log(log_level level, const char *fmt, ...);The log level log_level The definition of level is as follows:
namespace log4cpp {
enum class log_level {
FATAL = 0, ERROR = 1, WARN = 2, INFO = 3, DEBUG = 4, TRACE = 5
};
}Description:
FATAL: fatal errorERROR: errorWARN: warningINFO: informationDEBUG: debuggingTRACE: tracing
#include <thread>
#ifdef __GNUC__
#include <pthread.h>
#endif
#include "log4cpp.hpp"
void set_thread_name(const char *name) {
#ifdef __GNUC__
pthread_setname_np(pthread_self(), name);
#elif __linux__
prctl(PR_SET_NAME, reinterpret_cast<unsigned long>("child"));
#endif
}
void thread_routine() {
set_thread_name("child");
std::shared_ptr<log4cpp::layout> log = log4cpp::layout_manager::get_layout("recordLayout");
log->trace("this is a trace");
log->info("this is a info");
log->debug("this is a debug");
log->warn("this is an warning");
log->error("this is an error");
log->fatal("this is a fatal");
}
int main() {
std::thread t(thread_routine);
set_thread_name("main");
std::shared_ptr<log4cpp::layout> log = log4cpp::layout_manager::get_layout("console_layout");
log->trace("this is a trace");
log->info("this is a info");
log->debug("this is a debug");
log->warn("this is an warning");
log->error("this is an error");
log->fatal("this is a fatal");
t.join();
return 0;
}CMakeLists.txt example:
set(TARGET_NAME demo)
add_executable(${TARGET_NAME} demo.cpp)
set(EXECUTABLE_OUTPUT_PATH ${PROJECT_BINARY_DIR}/bin)
set(LIBRARY_OUTPUT_PATH ${PROJECT_BINARY_DIR}/lib)
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/lib)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/lib)
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/bin)
file(COPY ./log4cpp.json DESTINATION ${EXECUTABLE_OUTPUT_PATH})
include(FetchContent)
FetchContent_Declare(log4cpp GIT_REPOSITORY https://github.com/SandroDickens/log4cpp.git GIT_TAG v3.0.5)
FetchContent_MakeAvailable(log4cpp)
target_link_libraries(${TARGET_NAME} log4cpp)
if (CMAKE_HOST_UNIX)
target_link_libraries(demo pthread)
endif ()Output log example:
2025-01-02 22:53:04:329 [ main] [INFO ] -- this is a info
2025-01-02 22:53:04:329 [ child] [ERROR] -- this is an error
2025-01-02 22:53:04:329 [ main] [WARN ] -- this is an warning
2025-01-02 22:53:04:329 [ child] [FATAL] -- this is a fatal
2025-01-02 22:53:04:329 [ main] [ERROR] -- this is an error
2025-01-02 22:53:04:329 [ main] [FATAL] -- this is a fatalConfiguration file:
A sample configuration file is here
Welcome to submit PR. There are some things to know before submitting PR:
This project will first search for local boost, if not found then download from github
If CMake does not automatically find the Boost path, you can manually set the Boost path:
if (CMAKE_HOST_WIN32)
if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
set(BOOST_ROOT "D:/OpenCode/boost/gcc")
elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
set(BOOST_ROOT "D:/OpenCode/boost/msvc")
endif ()
else ()
set(BOOST_ROOT "/usr/local/boost")
endif ()cmake -S . -B build -DENABLE_DEMO=ON -DENABLE_TESTS=ON -DENABLE_ASAN=ONcmake --build build --config=Debugctest --test-dir buildOption description:
-DENABLE_DEMO=ON: compile demo, not compiled by default-DENABLE_TEST=ON: compile test, not enabled by default-DENABLE_ASAN=ON: enable address detection, not enabled by default
This project uses Google Test for unit testing. The test code is in the test directory. You are welcome to add test cases
If your code modifies existing functions, Please make sure that the test cases cover your changes
If your code modifies existing functions, please make sure that the ASAN test passes. Code that does not pass the ASAN test will not be merged
clang_rt.asan_dynamic-x86_64.dll is missing?
If "ENABLE_ASAN=ON" is set, and you are using the MSVC compiler, you may have this problem. The solution is:
Copy
"D:\Program Files\Microsoft Visual Studio\<Visual Studio Version>\Professional\VC\Tools\MSVC\<MSVC Version>\bin\Hostx64\x64\clang_rt.asan_dynamic-x86_64.dll"
to the cmake-build-debug/bin/
This project uses the LGPLv3 license