#1838 Add ANSI-colored non-rotating file sink.

README.md

@@ -117,6 +117,22 @@ void basic_logfile_example()
 }
 ```
 ---
+#### ANSI-colored file logger
+```c++
+#include "spdlog/sinks/ansicolor_file_sink.h"
+void ansicolor_logfile_example()
+{
+    try
+    {
+        auto logger = spdlog::ansicolor_logger_mt("ansi_logger", "logs/ansicolor-log.txt");
+    }
+    catch (const spdlog::spdlog_ex &ex)
+    {
+        std::cout << "Log init failed: " << ex.what() << std::endl;
+    }
+}
+```
+---
 #### Rotating files
 ```c++
 #include "spdlog/sinks/rotating_file_sink.h"

example/example.cpp

@@ -10,6 +10,7 @@
 void load_levels_example();
 void stdout_logger_example();
 void basic_example();
+void ansicolor_example();
 void rotating_example();
 void ansicolor_rotating_example();
 void daily_example();
@@ -71,6 +72,7 @@ int main(int, char *[]) {
     try {
         stdout_logger_example();
         basic_example();
+        ansicolor_example();
         rotating_example();
         ansicolor_rotating_example();
         daily_example();
@@ -123,6 +125,12 @@ void basic_example() {
     auto my_logger = spdlog::basic_logger_mt("file_logger", "logs/basic-log.txt", true);
 }
 
+#include "spdlog/sinks/ansicolor_file_sink.h"
+void ansicolor_example() {
+    // Create ANSI-colored file logger (not rotated).
+    auto my_logger = spdlog::ansicolor_logger_mt("ansi_logger", "logs/ansicolor-log.txt", true);
+}
+
 #include "spdlog/sinks/rotating_file_sink.h"
 void rotating_example() {
     // Create a file rotating logger with 5mb size max and 3 rotated files.

include/spdlog/details/ansicolors-inl.h

@@ -10,6 +10,41 @@
 namespace spdlog {
 namespace details {
 
+// Formatting codes
+constexpr const char* ansicolors::reset;
+constexpr const char* ansicolors::bold;
+constexpr const char* ansicolors::dark;
+constexpr const char* ansicolors::underline;
+constexpr const char* ansicolors::blink;
+constexpr const char* ansicolors::reverse;
+constexpr const char* ansicolors::concealed;
+constexpr const char* ansicolors::clear_line;
+
+// Foreground colors
+constexpr const char* ansicolors::black;
+constexpr const char* ansicolors::red;
+constexpr const char* ansicolors::green;
+constexpr const char* ansicolors::yellow;
+constexpr const char* ansicolors::blue;
+constexpr const char* ansicolors::magenta;
+constexpr const char* ansicolors::cyan;
+constexpr const char* ansicolors::white;
+
+/// Background colors
+constexpr const char* ansicolors::on_black;
+constexpr const char* ansicolors::on_red;
+constexpr const char* ansicolors::on_green;
+constexpr const char* ansicolors::on_yellow;
+constexpr const char* ansicolors::on_blue;
+constexpr const char* ansicolors::on_magenta;
+constexpr const char* ansicolors::on_cyan;
+constexpr const char* ansicolors::on_white;
+
+/// Bold colors
+constexpr const char* ansicolors::yellow_bold;
+constexpr const char* ansicolors::red_bold;
+constexpr const char* ansicolors::bold_on_red;
+
 SPDLOG_INLINE ansicolors::ansicolors() {
     colors_.at(level::trace) = to_string_(white);
     colors_.at(level::debug) = to_string_(cyan);
@@ -25,7 +60,7 @@ SPDLOG_INLINE void ansicolors::set_color(level::level_enum color_level, string_v
 }
 
 SPDLOG_INLINE std::vector<string_view_t> ansicolors::ranges(
-    const details::log_msg &msg, const memory_buf_t &formatted_msg) const {
+    const details::log_msg& msg, const memory_buf_t& formatted_msg) const {
     std::vector<string_view_t> result{};
     if (msg.color_range_end > msg.color_range_start) {
         // before color range
@@ -49,7 +84,7 @@ SPDLOG_INLINE std::vector<string_view_t> ansicolors::ranges(
     return result;
 }
 
-SPDLOG_INLINE std::string ansicolors::to_string_(const string_view_t &sv) {
+SPDLOG_INLINE std::string ansicolors::to_string_(const string_view_t& sv) {
     return std::string(sv.data(), sv.size());
 }
 

include/spdlog/sinks/ansicolor_file_sink-inl.h

@@ -0,0 +1,52 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#ifndef SPDLOG_HEADER_ONLY
+    #include <spdlog/sinks/ansicolor_file_sink.h>
+#endif
+
+#include <spdlog/common.h>
+#include <spdlog/details/os.h>
+
+namespace spdlog {
+namespace sinks {
+
+template <typename Mutex>
+SPDLOG_INLINE ansicolor_file_sink<Mutex>::ansicolor_file_sink(
+    const filename_t &filename, bool truncate, const file_event_handlers &event_handlers)
+    : file_helper_{event_handlers} {
+    file_helper_.open(filename, truncate);
+}
+
+template <typename Mutex>
+SPDLOG_INLINE void ansicolor_file_sink<Mutex>::set_color(level::level_enum color_level,
+                                                         string_view_t color) {
+    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+    colors_.set_color(color_level, color);
+}
+
+template <typename Mutex>
+SPDLOG_INLINE const filename_t &ansicolor_file_sink<Mutex>::filename() const {
+    return file_helper_.filename();
+}
+
+template <typename Mutex>
+SPDLOG_INLINE void ansicolor_file_sink<Mutex>::sink_it_(const details::log_msg &msg) {
+    msg.color_range_start = 0;
+    msg.color_range_end = 0;
+    memory_buf_t formatted;
+    base_sink<Mutex>::formatter_->format(msg, formatted);
+    for (const auto &range : colors_.ranges(msg, formatted)) {
+        file_helper_.write(range);
+    }
+}
+
+template <typename Mutex>
+SPDLOG_INLINE void ansicolor_file_sink<Mutex>::flush_() {
+    file_helper_.flush();
+}
+
+}  // namespace sinks
+}  // namespace spdlog

include/spdlog/sinks/ansicolor_file_sink.h

@@ -0,0 +1,68 @@
+// Copyright(c) 2015-present, Gabi Melman & spdlog contributors.
+// Distributed under the MIT License (http://opensource.org/licenses/MIT)
+
+#pragma once
+
+#include <spdlog/details/ansicolors.h>
+#include <spdlog/details/file_helper.h>
+#include <spdlog/details/null_mutex.h>
+#include <spdlog/details/synchronous_factory.h>
+#include <spdlog/sinks/base_sink.h>
+
+#include <mutex>
+#include <string>
+
+namespace spdlog {
+namespace sinks {
+/*
+ * ANSI-colored file sink with single file as target
+ */
+template <typename Mutex>
+class ansicolor_file_sink final : public base_sink<Mutex> {
+public:
+    explicit ansicolor_file_sink(const filename_t &filename,
+                                 bool truncate = false,
+                                 const file_event_handlers &event_handlers = {});
+    void set_color(level::level_enum color_level, string_view_t color);
+    const filename_t &filename() const;
+
+protected:
+    void sink_it_(const details::log_msg &msg) override;
+    void flush_() override;
+
+private:
+    details::ansicolors colors_;
+    details::file_helper file_helper_;
+};
+
+using ansicolor_file_sink_mt = ansicolor_file_sink<std::mutex>;
+using ansicolor_file_sink_st = ansicolor_file_sink<details::null_mutex>;
+
+}  // namespace sinks
+
+//
+// factory functions
+//
+template <typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> ansicolor_logger_mt(const std::string &logger_name,
+                                                   const filename_t &filename,
+                                                   bool truncate = false,
+                                                   const file_event_handlers &event_handlers = {}) {
+    return Factory::template create<sinks::ansicolor_file_sink_mt>(logger_name, filename, truncate,
+                                                                   event_handlers);
+}
+
+template <typename Factory = spdlog::synchronous_factory>
+inline std::shared_ptr<logger> ansicolor_logger_st(const std::string &logger_name,
+                                                   const filename_t &filename,
+                                                   bool truncate = false,
+                                                   const file_event_handlers &event_handlers = {}) {
+    return Factory::template create<sinks::ansicolor_file_sink_st>(logger_name, filename, truncate,
+                                                                   event_handlers);
+}
+
+}  // namespace spdlog
+
+#ifdef SPDLOG_HEADER_ONLY
+    #include "ansicolor_file_sink-inl.h"
+#endif

src/file_sinks.cpp

@@ -15,6 +15,10 @@
 template class SPDLOG_API spdlog::sinks::basic_file_sink<std::mutex>;
 template class SPDLOG_API spdlog::sinks::basic_file_sink<spdlog::details::null_mutex>;
 
+#include <spdlog/sinks/ansicolor_file_sink-inl.h>
+template class SPDLOG_API spdlog::sinks::ansicolor_file_sink<std::mutex>;
+template class SPDLOG_API spdlog::sinks::ansicolor_file_sink<spdlog::details::null_mutex>;
+
 #include <spdlog/sinks/rotating_file_sink-inl.h>
 template class SPDLOG_API spdlog::sinks::rotating_file_sink<std::mutex>;
 template class SPDLOG_API spdlog::sinks::rotating_file_sink<spdlog::details::null_mutex>;

tests/includes.h

@@ -28,6 +28,7 @@
 #include "spdlog/details/fmt_helper.h"
 #include "spdlog/mdc.h"
 #include "spdlog/sinks/basic_file_sink.h"
+#include "spdlog/sinks/ansicolor_file_sink.h"
 #include "spdlog/sinks/daily_file_sink.h"
 #include "spdlog/sinks/null_sink.h"
 #include "spdlog/sinks/ostream_sink.h"

tests/test_file_logging.cpp

@@ -45,6 +45,33 @@ TEST_CASE("flush_on", "[flush_on]") {
                                     default_eol, default_eol, default_eol));
 }
 
+TEST_CASE("ansicolor_file_logger", "[ansicolor_logger]") {
+    prepare_logdir();
+    spdlog::filename_t filename = SPDLOG_FILENAME_T(SIMPLE_LOG);
+
+    // auto logger = spdlog::details::make_unique<spdlog::sinks::ansicolor_file_sink_mt>(filename);
+    auto logger = spdlog::create<spdlog::sinks::ansicolor_file_sink_mt>("logger", filename);
+    logger->set_pattern("[%^+++%$] %v");
+
+    auto sink =
+        std::dynamic_pointer_cast<spdlog::sinks::ansicolor_file_sink_mt>(logger->sinks().front());
+    sink->set_color(spdlog::level::info, spdlog::details::ansicolors::blue);
+
+    logger->info("Test message {}", 1);
+    logger->info("Test message {}", 2);
+
+    logger->flush();
+    require_message_count(SIMPLE_LOG, 2);
+    using spdlog::details::os::default_eol;
+    REQUIRE(file_contents(SIMPLE_LOG) ==
+            spdlog::fmt_lib::format(
+                "[{ansi_blue}+++{ansi_reset}] Test message 1{eol}"
+                "[{ansi_blue}+++{ansi_reset}] Test message 2{eol}",
+                spdlog::fmt_lib::arg("ansi_blue", spdlog::details::ansicolors::blue),
+                spdlog::fmt_lib::arg("ansi_reset", spdlog::details::ansicolors::reset),
+                spdlog::fmt_lib::arg("eol", default_eol)));
+}
+
 TEST_CASE("rotating_file_logger1", "[rotating_logger]") {
     prepare_logdir();
     size_t max_size = 1024 * 10;