feat: add configurable logger system with spdlog backend

CMakeLists.txt

@@ -64,6 +64,7 @@ find_package(OpenSSL REQUIRED)
 find_package(ZLIB REQUIRED)
 find_package(Backward CONFIG REQUIRED)
 find_package(absl REQUIRED)
+find_package(spdlog CONFIG REQUIRED)
 
 # Find gperftools via pkg-config
 find_package(PkgConfig REQUIRED)
@@ -98,11 +99,15 @@ set(PROFILER_SOURCES
     src/symbolize.cpp
     src/web_resources.cpp
     src/web_server.cpp
+    src/internal/log_manager.cpp
+    src/internal/default_log_sink.cpp
 )
 
 set(PROFILER_HEADERS
     include/profiler_manager.h
     include/web_server.h
+    include/profiler/log_sink.h
+    include/profiler/logger.h
 )
 
 # Create library
@@ -116,6 +121,8 @@ target_link_libraries(profiler_lib
         absl::stacktrace
         absl::debugging_internal
         absl::demangle_internal
+        spdlog::spdlog
+        Drogon::Drogon
         pthread
         ${CMAKE_DL_LIBS}
     PUBLIC
@@ -170,6 +177,17 @@ if(REMOTE_PROFILER_BUILD_TESTS)
     )
 
     add_test(NAME FullFlowTest COMMAND test_full_flow)
+
+    # Logger 测试
+    add_executable(test_logger tests/test_logger.cpp)
+    target_link_libraries(test_logger
+        profiler_lib
+        GTest::gtest
+        GTest::gtest_main
+        pthread
+    )
+
+    add_test(NAME LoggerTest COMMAND test_logger)
     message(STATUS "Tests will be built")
 else()
     message(STATUS "Tests disabled")
@@ -199,6 +217,13 @@ if(REMOTE_PROFILER_INSTALL)
         DESTINATION include/cpp-remote-profiler
     )
 
+    # Install profiler subdirectory headers
+    install(FILES
+        include/profiler/log_sink.h
+        include/profiler/logger.h
+        DESTINATION include/cpp-remote-profiler/profiler
+    )
+
     # Install version header
     install(FILES include/version.h
         DESTINATION include/cpp-remote-profiler

docs/user_guide/02_api_reference.md

@@ -5,6 +5,7 @@
 ## 目录
 - [ProfilerManager](#profilermanager)
 - [类型定义](#类型定义)
+- [日志系统 API](#日志系统-api)
 - [CPU Profiling API](#cpu-profiling-api)
 - [Heap Profiling API](#heap-profiling-api)
 - [线程堆栈 API](#线程堆栈-api)
@@ -75,6 +76,211 @@ struct ThreadStackTrace {
 
 ---
 
+## 日志系统 API
+
+profiler 库提供可配置的日志系统，允许用户将 profiler 的日志集成到自己的日志系统中。
+
+### LogLevel
+
+日志级别枚举。
+
+```cpp
+enum class LogLevel {
+    Trace,    // 详细调试信息
+    Debug,    // 调试信息
+    Info,     // 一般信息（默认级别）
+    Warning,  // 警告信息
+    Error,    // 错误信息
+    Fatal     // 致命错误
+};
+```
+
+---
+
+### LogSink
+
+日志输出接口，用户可继承此类实现自定义日志输出。
+
+```cpp
+class LogSink {
+public:
+    virtual ~LogSink() = default;
+
+    /// @brief 写入日志消息
+    /// @param level 日志级别
+    /// @param file 源文件名（可能为 nullptr）
+    /// @param line 源行号
+    /// @param function 函数名（可能为 nullptr）
+    /// @param message 格式化后的日志消息
+    virtual void log(LogLevel level,
+                     const char* file,
+                     int line,
+                     const char* function,
+                     const char* message) = 0;
+
+    /// @brief 刷新缓冲区（可选实现）
+    virtual void flush() {}
+};
+```
+
+**说明**:
+- 实现自定义 sink 后，通过 `setSink()` 注入到 profiler
+- 设置自定义 sink 后，默认的 stderr 输出将被替换
+- 所有参数的生命周期仅在 `log()` 调用期间有效，如需保留请复制
+
+---
+
+### setSink
+
+设置自定义日志 sink。
+
+```cpp
+void setSink(std::shared_ptr<LogSink> sink);
+```
+
+**参数**:
+- `sink`: 自定义 LogSink 的 shared_ptr，传 `nullptr` 恢复默认 sink
+
+**说明**:
+- 设置后，profiler 的所有日志将输出到自定义 sink
+- 默认 sink 输出到 stderr（使用 spdlog）
+- 设置 `nullptr` 可恢复默认行为
+
+**示例**:
+```cpp
+#include <profiler/log_sink.h>
+#include <profiler/logger.h>
+
+// 自定义 sink：集成到应用日志系统
+class MyAppLogSink : public profiler::LogSink {
+public:
+    void log(profiler::LogLevel level, const char* file, int line,
+             const char* function, const char* message) override {
+        // 转发到应用的日志系统
+        switch (level) {
+            case profiler::LogLevel::Error:
+                MY_APP_ERROR("[Profiler] {}:{} - {}", file, line, message);
+                break;
+            case profiler::LogLevel::Warning:
+                MY_APP_WARN("[Profiler] {}:{} - {}", file, line, message);
+                break;
+            default:
+                MY_APP_INFO("[Profiler] {}:{} - {}", file, line, message);
+                break;
+        }
+    }
+};
+
+// 设置自定义 sink
+profiler::setSink(std::make_shared<MyAppLogSink>());
+
+// 恢复默认 sink
+profiler::setSink(nullptr);
+```
+
+---
+
+### setLogLevel
+
+设置最小日志级别。
+
+```cpp
+void setLogLevel(LogLevel level);
+```
+
+**参数**:
+- `level`: 最小日志级别，低于此级别的消息将被过滤
+
+**说明**:
+- 默认级别为 `LogLevel::Info`
+- 日志级别从低到高：Trace < Debug < Info < Warning < Error < Fatal
+
+**示例**:
+```cpp
+#include <profiler/logger.h>
+
+// 启用调试日志
+profiler::setLogLevel(profiler::LogLevel::Debug);
+
+// 只显示错误和致命错误
+profiler::setLogLevel(profiler::LogLevel::Error);
+
+// 显示所有日志（包括 Trace）
+profiler::setLogLevel(profiler::LogLevel::Trace);
+```
+
+---
+
+### 完整示例：集成到 spdlog
+
+```cpp
+#include <profiler/log_sink.h>
+#include <profiler/logger.h>
+#include <spdlog/spdlog.h>
+
+class SpdlogSink : public profiler::LogSink {
+public:
+    void log(profiler::LogLevel level, const char* file, int line,
+             const char* function, const char* message) override {
+        // 映射日志级别
+        spdlog::level::level_enum spdlog_level;
+        switch (level) {
+            case profiler::LogLevel::Trace:    spdlog_level = spdlog::level::trace; break;
+            case profiler::LogLevel::Debug:    spdlog_level = spdlog::level::debug; break;
+            case profiler::LogLevel::Info:     spdlog_level = spdlog::level::info; break;
+            case profiler::LogLevel::Warning:  spdlog_level = spdlog::level::warn; break;
+            case profiler::LogLevel::Error:    spdlog_level = spdlog::level::err; break;
+            case profiler::LogLevel::Fatal:    spdlog_level = spdlog::level::critical; break;
+        }
+
+        // 输出到 spdlog
+        spdlog::log(spdlog::level::info, "[Profiler] {}:{} - {}", file, line, message);
+    }
+
+    void flush() override {
+        spdlog::default_logger()->flush();
+    }
+};
+
+int main() {
+    // 配置 spdlog
+    spdlog::set_level(spdlog::level::debug);
+    spdlog::set_pattern("[%Y-%m-%d %H:%M:%S.%e] [%l] %v");
+
+    // 集成 profiler 日志到 spdlog
+    profiler::setSink(std::make_shared<SpdlogSink>());
+    profiler::setLogLevel(profiler::LogLevel::Debug);
+
+    // 使用 profiler...
+}
+```
+
+---
+
+### 完整示例：完全禁用日志
+
+```cpp
+#include <profiler/log_sink.h>
+#include <profiler/logger.h>
+
+// 空 sink：丢弃所有日志
+class NullSink : public profiler::LogSink {
+public:
+    void log(profiler::LogLevel, const char*, int,
+             const char*, const char*) override {
+        // 什么都不做
+    }
+};
+
+// 方法 1：使用空 sink
+profiler::setSink(std::make_shared<NullSink>());
+
+// 方法 2：设置日志级别为 Fatal（只显示致命错误）
+profiler::setLogLevel(profiler::LogLevel::Fatal);
+```
+
+---
+
 ## CPU Profiling API
 
 ### startCPUProfiler

include/profiler/log_sink.h

@@ -0,0 +1,59 @@
+/// @file log_sink.h
+/// @brief Log sink interface for custom logging implementations
+
+#pragma once
+
+#include "profiler_version.h"
+#include <string>
+
+PROFILER_NAMESPACE_BEGIN
+
+/// @enum LogLevel
+/// @brief Log severity levels
+enum class LogLevel {
+    Trace,   ///< Detailed debug information
+    Debug,   ///< Debug information
+    Info,    ///< General information
+    Warning, ///< Warning messages
+    Error,   ///< Error messages
+    Fatal    ///< Fatal errors (typically terminates program)
+};
+
+/// @class LogSink
+/// @brief Abstract interface for custom log output destinations
+///
+/// Users can inherit from this class to implement custom logging behavior,
+/// such as integrating with their application's logging system.
+///
+/// @example
+/// @code
+/// class MyLogSink : public profiler::LogSink {
+/// public:
+///     void log(profiler::LogLevel level, const char* file, int line,
+///              const char* function, const char* message) override {
+///         // Forward to your application's logger
+///         MyAppLogger::log(level, file, line, message);
+///     }
+/// };
+///
+/// // Set custom sink
+/// profiler::setSink(std::make_shared<MyLogSink>());
+/// @endcode
+class LogSink {
+public:
+    virtual ~LogSink() = default;
+
+    /// @brief Write a log message
+    /// @param level Log severity level
+    /// @param file Source file name (may be nullptr)
+    /// @param line Source line number
+    /// @param function Function name (may be nullptr)
+    /// @param message Formatted log message
+    virtual void log(LogLevel level, const char* file, int line, const char* function, const char* message) = 0;
+
+    /// @brief Flush any buffered log output
+    /// @note Default implementation does nothing
+    virtual void flush() {}
+};
+
+PROFILER_NAMESPACE_END

include/profiler/logger.h

@@ -0,0 +1,45 @@
+/// @file logger.h
+/// @brief Logger configuration interface
+
+#pragma once
+
+#include "log_sink.h"
+#include <memory>
+
+PROFILER_NAMESPACE_BEGIN
+
+/// @brief Set a custom log sink for the profiler
+/// @param sink Shared pointer to a LogSink implementation
+///
+/// When a custom sink is set, all profiler log messages will be
+/// forwarded to this sink instead of the default output.
+///
+/// Pass nullptr to revert to the default sink.
+///
+/// @example
+/// @code
+/// // Use custom sink
+/// profiler::setSink(std::make_shared<MyLogSink>());
+///
+/// // Revert to default
+/// profiler::setSink(nullptr);
+/// @endcode
+void setSink(std::shared_ptr<LogSink> sink);
+
+/// @brief Set the minimum log level
+/// @param level Minimum level for messages to be output
+///
+/// Messages with a level lower than the specified level will be suppressed.
+/// Default level is LogLevel::Info.
+///
+/// @example
+/// @code
+/// // Enable debug logging
+/// profiler::setLogLevel(profiler::LogLevel::Debug);
+///
+/// // Suppress all but errors
+/// profiler::setLogLevel(profiler::LogLevel::Error);
+/// @endcode
+void setLogLevel(LogLevel level);
+
+PROFILER_NAMESPACE_END