kcenon::logger::console_writer Class Reference

Core console writer for logging to stdout/stderr. More...

#include <console_writer.h>

Inheritance diagram for kcenon::logger::console_writer:

Collaboration diagram for kcenon::logger::console_writer:

Public Member Functions
	console_writer (bool use_stderr=false, bool auto_detect_color=true, std::unique_ptr< log_formatter_interface > formatter=nullptr)
	Constructor.
	~console_writer () override
	Destructor.
	console_writer (const console_writer &)=delete
console_writer &	operator= (const console_writer &)=delete
	console_writer (console_writer &&)=delete
console_writer &	operator= (console_writer &&)=delete
common::VoidResult	write (const log_entry &entry) override
	Write a log entry to console.
common::VoidResult	flush () override
	Flush console streams.
std::string	get_name () const override
	Get writer name.
bool	is_healthy () const override
	Check if writer is healthy.
void	set_use_stderr (bool use_stderr)
	Set whether to use stderr for all output.
void	set_use_color (bool use_color)
	Set whether to use color output (if supported)
bool	use_color () const
	Get current color output setting.
void	set_integrity_policy (std::shared_ptr< security::integrity_policy > policy)
	Enable tamper-evident integrity signing for every console record.
Public Member Functions inherited from kcenon::logger::log_writer_interface
virtual	~log_writer_interface ()=default
virtual common::VoidResult	close ()
	Close the writer and release resources.
virtual auto	is_open () const -> bool
	Check if writer is open and ready.

Protected Member Functions
std::string	format_entry (const log_entry &entry) const
	Format a log entry using the current formatter.
std::mutex &	get_mutex () const
	Access the writer mutex for extended operations.

Private Member Functions
bool	is_color_supported () const
	Check if terminal supports color.

Private Attributes
bool	use_stderr_
bool	use_color_ {true}
std::unique_ptr< log_formatter_interface >	formatter_
std::shared_ptr< security::integrity_policy >	integrity_policy_
std::mutex	mutex_

Additional Inherited Members
Static Public Attributes inherited from kcenon::logger::sync_writer_tag
static constexpr writer_category	category = writer_category::synchronous

Detailed Description

Core console writer for logging to stdout/stderr.

Pure console I/O implementation with direct mutex management. Designed to serve as the base layer in Decorator pattern compositions.

Features:

• Color support for different log levels (if terminal supports it)
• Thread-safe console output with internal mutex synchronization
• Error levels go to stderr, others to stdout

Category: Synchronous (blocking I/O to console)

Since

1.0.0

1.3.0 Refactored to use thread_safe_writer base class

1.4.0 Added sync_writer_tag for category classification

4.0.0 Refactored for Decorator pattern with simplified inheritance

4.1.0 Directly implements log_writer_interface as core writer

Examples

composite_writer_example.cpp, and decorator_usage.cpp.

Definition at line 48 of file console_writer.h.

Constructor & Destructor Documentation

console_writer() [1/3]

kcenon::logger::console_writer::console_writer ( bool use_stderr = false, bool auto_detect_color = true, std::unique_ptr< log_formatter_interface > formatter = nullptr )

explicit

Constructor.

Parameters

use_stderr	If true, all output goes to stderr (default: false)
auto_detect_color	Auto-detect terminal color support (default: true)
formatter	Custom log formatter (default: timestamp formatter)

Definition at line 26 of file console_writer.cpp.

    : use_stderr_(use_stderr)
    , formatter_(formatter ? std::move(formatter) : std::make_unique<timestamp_formatter>()) {
    if (auto_detect_color) {
        set_use_color(is_color_supported());
    } else {
        // Apply color setting to formatter
        auto opts = formatter_->get_options();
        opts.use_colors = use_color_;
        formatter_->set_options(opts);
    }
}

References formatter_, is_color_supported(), set_use_color(), and use_color_.

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~console_writer()

kcenon::logger::console_writer::~console_writer ( )

override

Destructor.

Definition at line 41 of file console_writer.cpp.

                                {
    flush();
}

References flush().

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console_writer() [2/3]

kcenon::logger::console_writer::console_writer ( const console_writer & )

delete

console_writer() [3/3]

kcenon::logger::console_writer::console_writer ( console_writer && )

delete

Member Function Documentation

flush()

common::VoidResult kcenon::logger::console_writer::flush ( )

overridevirtual

Flush console streams.

Returns

common::VoidResult Success or error code

Implements kcenon::logger::log_writer_interface.

Definition at line 104 of file console_writer.cpp.

                                       {
    std::lock_guard<std::mutex> lock(mutex_);
    return utils::try_write_operation([&]() -> common::VoidResult {
        std::cout.flush();
        std::cerr.flush();
 
        if (std::cout.fail() || std::cerr.fail()) {
            return make_logger_void_result(logger_error_code::flush_timeout, "Console flush failed");
        }
 
        return common::ok();
    }, logger_error_code::flush_timeout);
}

References kcenon::logger::flush_timeout, kcenon::logger::make_logger_void_result(), mutex_, kcenon::common::ok(), and kcenon::logger::utils::try_write_operation().

Referenced by ~console_writer().

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format_entry()

std::string kcenon::logger::console_writer::format_entry ( const log_entry & entry ) const

protected

Format a log entry using the current formatter.

Definition at line 146 of file console_writer.cpp.

                                                                   {
    if (!formatter_) {
        // Fallback if formatter is somehow null
        return entry.message.to_string();
    }
    return formatter_->format(entry);
}

References formatter_, kcenon::logger::log_entry::message, and kcenon::logger::small_string< SSO_SIZE >::to_string().

Referenced by write().

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get_mutex()

std::mutex & kcenon::logger::console_writer::get_mutex ( ) const

inlineprotected

Access the writer mutex for extended operations.

Returns

Reference to the internal mutex

Definition at line 132 of file console_writer.h.

{ return mutex_; }

get_name()

std::string kcenon::logger::console_writer::get_name ( ) const

inlineoverridevirtual

Get writer name.

Implements kcenon::logger::log_writer_interface.

Examples

decorator_usage.cpp.

Definition at line 87 of file console_writer.h.

{ return "console"; }

Referenced by example_core_writers().

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is_color_supported()

bool kcenon::logger::console_writer::is_color_supported ( ) const

private

Check if terminal supports color.

Returns

true if color is supported

Definition at line 154 of file console_writer.cpp.

                                              {
#ifdef _WIN32
    // Check if running in Windows Terminal or if ANSI is enabled
    HANDLE hOut = GetStdHandle(STD_OUTPUT_HANDLE);
    if (hOut == INVALID_HANDLE_VALUE) {
        return false;
    }
    
    DWORD dwMode = 0;
    if (!GetConsoleMode(hOut, &dwMode)) {
        return false;
    }
    
    // Check for ENABLE_VIRTUAL_TERMINAL_PROCESSING flag
    return (dwMode & 0x0004) != 0;
#else
    // Check if output is to a terminal and TERM is set
    const char* term = std::getenv("TERM");
    return isatty(STDOUT_FILENO) && term && std::string(term) != "dumb";
#endif
}

Referenced by console_writer().

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is_healthy()

bool kcenon::logger::console_writer::is_healthy ( ) const

overridevirtual

Check if writer is healthy.

Implements kcenon::logger::log_writer_interface.

Definition at line 118 of file console_writer.cpp.

                                      {
    return std::cout.good() && std::cerr.good();
}

operator=() [1/2]

console_writer & kcenon::logger::console_writer::operator= ( console_writer && )

delete

operator=() [2/2]

console_writer & kcenon::logger::console_writer::operator= ( const console_writer & )

delete

set_integrity_policy()

void kcenon::logger::console_writer::set_integrity_policy

(

std::shared_ptr< security::integrity_policy >

policy

)

Enable tamper-evident integrity signing for every console record.

Parameters

policy

Signing policy (shared ownership); pass nullptr to disable.

When a policy is installed, each emitted line is suffixed with a SIGNATURE[<policy>]:<hex> token (Issue #612). Consumers piping the console output to a log collector can re-verify each record.

Definition at line 140 of file console_writer.cpp.

                                                    {
    std::lock_guard<std::mutex> lock(mutex_);
    integrity_policy_ = std::move(policy);
}

References integrity_policy_, and mutex_.

set_use_color()

void kcenon::logger::console_writer::set_use_color

(

bool

use_color

)

Set whether to use color output (if supported)

Parameters

use_color

true to enable color output, false to disable

Definition at line 127 of file console_writer.cpp.

                                                 {
    use_color_ = use_color;
    if (formatter_) {
        auto opts = formatter_->get_options();
        opts.use_colors = use_color_;
        formatter_->set_options(opts);
    }
}

References formatter_, use_color(), and use_color_.

Referenced by console_writer().

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set_use_stderr()

void kcenon::logger::console_writer::set_use_stderr

(

bool

use_stderr

)

Set whether to use stderr for all output.

Parameters

use_stderr

Enable/disable stderr usage

Definition at line 122 of file console_writer.cpp.

                                                   {
    std::lock_guard<std::mutex> lock(mutex_);
    use_stderr_ = use_stderr;
}

References mutex_, and use_stderr_.

use_color()

bool kcenon::logger::console_writer::use_color

(

)

const

Get current color output setting.

Returns

true if color output is enabled, false otherwise

Definition at line 136 of file console_writer.cpp.

                                     {
    return use_color_;
}

References use_color_.

Referenced by set_use_color(), and write().

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write()

common::VoidResult kcenon::logger::console_writer::write ( const log_entry & entry )

overridevirtual

Write a log entry to console.

Parameters

entry

The log entry to write

Returns

common::VoidResult Success or error code

Implements kcenon::logger::log_writer_interface.

Examples

composite_writer_example.cpp.

Definition at line 45 of file console_writer.cpp.

                                                             {
    std::lock_guard<std::mutex> lock(mutex_);
    return utils::try_write_operation([&]() -> common::VoidResult {
        // Convert logger_system::log_level to common::interfaces::log_level for comparison
        auto level = static_cast<common::interfaces::log_level>(static_cast<int>(entry.level));
 
        // Route error/fatal to stderr; everything less severe to stdout.
        // log_level values are ordered by severity (trace=0 ... fatal=5),
        // so >= error selects the high-severity bucket.
        auto& stream = (use_stderr_ || level >= common::interfaces::log_level::error)
                       ? std::cerr : std::cout;
 
        if (use_color()) {
            // Simple color mapping based on level
            switch (level) {
                case common::interfaces::log_level::fatal:
                case common::interfaces::log_level::error:
                    stream << "\033[31m"; // Red
                    break;
                case common::interfaces::log_level::warning:
                    stream << "\033[33m"; // Yellow
                    break;
                case common::interfaces::log_level::info:
                    stream << "\033[32m"; // Green
                    break;
                case common::interfaces::log_level::debug:
                    stream << "\033[36m"; // Cyan
                    break;
                case common::interfaces::log_level::trace:
                    stream << "\033[37m"; // White
                    break;
                default:
                    break;
            }
        }
 
        std::string formatted = format_entry(entry);
 
        // Append tamper-evident signature (Issue #612) when configured.
        // Color reset is emitted first so the signature is never colorized
        // and stays machine-readable by downstream collectors.
        stream << formatted;
 
        if (use_color()) {
            stream << "\033[0m"; // Reset color
        }
 
        if (integrity_policy_) {
            stream << security::format_signature_suffix(
                *integrity_policy_, formatted);
        }
 
        stream << '\n';
 
        // Verify stream state
        return utils::check_stream_state(stream, "console write");
    }, logger_error_code::processing_failed);
}

References kcenon::logger::utils::check_stream_state(), format_entry(), kcenon::logger::security::format_signature_suffix(), integrity_policy_, kcenon::logger::log_entry::level, mutex_, kcenon::logger::processing_failed, kcenon::logger::utils::try_write_operation(), use_color(), and use_stderr_.

Referenced by main().

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Member Data Documentation

formatter_

std::unique_ptr<log_formatter_interface> kcenon::logger::console_writer::formatter_

private

Definition at line 144 of file console_writer.h.

Referenced by console_writer(), format_entry(), and set_use_color().

integrity_policy_

std::shared_ptr<security::integrity_policy> kcenon::logger::console_writer::integrity_policy_

private

Definition at line 145 of file console_writer.h.

Referenced by set_integrity_policy(), and write().

mutex_

std::mutex kcenon::logger::console_writer::mutex_

mutableprivate

Definition at line 146 of file console_writer.h.

Referenced by flush(), set_integrity_policy(), set_use_stderr(), and write().

use_color_

bool kcenon::logger::console_writer::use_color_ {true}

private

Definition at line 143 of file console_writer.h.

{true};

Referenced by console_writer(), set_use_color(), and use_color().

use_stderr_

bool kcenon::logger::console_writer::use_stderr_

private

Definition at line 142 of file console_writer.h.

Referenced by set_use_stderr(), and write().

---

The documentation for this class was generated from the following files:

• include/kcenon/logger/writers/console_writer.h
• src/impl/writers/console_writer.cpp