Add support for custom filename calculator in rotating_file_sink.

include/spdlog/sinks/rotating_file_sink-inl.h

-// 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/rotating_file_sink.h>
-#endif
-
-#include <spdlog/common.h>
-
-#include <spdlog/details/file_helper.h>
-#include <spdlog/details/null_mutex.h>
-#include <spdlog/fmt/fmt.h>
-
-#include <cerrno>
-#include <chrono>
-#include <ctime>
-#include <mutex>
-#include <string>
-#include <tuple>
-
-namespace spdlog {
-namespace sinks {
-
-template<typename Mutex>
-SPDLOG_INLINE rotating_file_sink<Mutex>::rotating_file_sink(
-    filename_t base_filename, std::size_t max_size, std::size_t max_files, bool rotate_on_open)
-    : base_filename_(std::move(base_filename))
-    , max_size_(max_size)
-    , max_files_(max_files)
-{
-    file_helper_.open(calc_filename(base_filename_, 0));
-    current_size_ = file_helper_.size(); // expensive. called only once
-    if (rotate_on_open && current_size_ > 0)
-    {
-        rotate_();
-    }
-}
-
-// calc filename according to index and file extension if exists.
-// e.g. calc_filename("logs/mylog.txt, 3) => "logs/mylog.3.txt".
-template<typename Mutex>
-SPDLOG_INLINE filename_t rotating_file_sink<Mutex>::calc_filename(const filename_t &filename, std::size_t index)
-{
-    if (index == 0u)
-    {
-        return filename;
-    }
-
-    filename_t basename, ext;
-    std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
-    return fmt::format(SPDLOG_FILENAME_T("{}.{}{}"), basename, index, ext);
-}
-
-template<typename Mutex>
-SPDLOG_INLINE filename_t rotating_file_sink<Mutex>::filename()
-{
-    std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
-    return file_helper_.filename();
-}
-
-template<typename Mutex>
-SPDLOG_INLINE void rotating_file_sink<Mutex>::sink_it_(const details::log_msg &msg)
-{
-    memory_buf_t formatted;
-    base_sink<Mutex>::formatter_->format(msg, formatted);
-    current_size_ += formatted.size();
-    if (current_size_ > max_size_)
-    {
-        rotate_();
-        current_size_ = formatted.size();
-    }
-    file_helper_.write(formatted);
-}
-
-template<typename Mutex>
-SPDLOG_INLINE void rotating_file_sink<Mutex>::flush_()
-{
-    file_helper_.flush();
-}
-
-// Rotate files:
-// log.txt -> log.1.txt
-// log.1.txt -> log.2.txt
-// log.2.txt -> log.3.txt
-// log.3.txt -> delete
-template<typename Mutex>
-SPDLOG_INLINE void rotating_file_sink<Mutex>::rotate_()
-{
-    using details::os::filename_to_str;
-    using details::os::path_exists;
-    file_helper_.close();
-    for (auto i = max_files_; i > 0; --i)
-    {
-        filename_t src = calc_filename(base_filename_, i - 1);
-        if (!path_exists(src))
-        {
-            continue;
-        }
-        filename_t target = calc_filename(base_filename_, i);
-
-        if (!rename_file_(src, target))
-        {
-            // if failed try again after a small delay.
-            // this is a workaround to a windows issue, where very high rotation
-            // rates can cause the rename to fail with permission denied (because of antivirus?).
-            details::os::sleep_for_millis(100);
-            if (!rename_file_(src, target))
-            {
-                file_helper_.reopen(true); // truncate the log file anyway to prevent it to grow beyond its limit!
-                current_size_ = 0;
-                throw_spdlog_ex("rotating_file_sink: failed renaming " + filename_to_str(src) + " to " + filename_to_str(target), errno);
-            }
-        }
-    }
-    file_helper_.reopen(true);
-}
-
-// delete the target if exists, and rename the src file  to target
-// return true on success, false otherwise.
-template<typename Mutex>
-SPDLOG_INLINE bool rotating_file_sink<Mutex>::rename_file_(const filename_t &src_filename, const filename_t &target_filename)
-{
-    // try to delete the target file in case it already exists.
-    (void)details::os::remove(target_filename);
-    return details::os::rename(src_filename, target_filename) == 0;
-}
-
-} // namespace sinks
-} // namespace spdlog

include/spdlog/sinks/rotating_file_sink.h

@@ -15,20 +15,68 @@
 namespace spdlog {
 namespace sinks {
 
+/*
+ * Generator of rotating log file names in format basename.index.extension
+ * e.g. calc_filename("logs/mylog.txt, 3) => "logs/mylog.3.txt".
+ */
+struct rotating_filename_calculator
+{
+    // Create filename for the form basename.index.extension
+    static filename_t calc_filename(const filename_t &filename, std::size_t index)
+    {
+        if (index == 0u)
+        {
+            return filename;
+        }
+
+        filename_t basename, ext;
+        std::tie(basename, ext) = details::file_helper::split_by_extension(filename);
+        return fmt::format(SPDLOG_FILENAME_T("{}.{}{}"), basename, index, ext);
+    }
+};
+
 //
 // Rotating file sink based on size
 //
-template<typename Mutex>
+template<typename Mutex, typename FileNameCalc = rotating_filename_calculator>
 class rotating_file_sink final : public base_sink<Mutex>
 {
 public:
-    rotating_file_sink(filename_t base_filename, std::size_t max_size, std::size_t max_files, bool rotate_on_open = false);
-    static filename_t calc_filename(const filename_t &filename, std::size_t index);
-    filename_t filename();
+    rotating_file_sink(filename_t base_filename, std::size_t max_size, std::size_t max_files, bool rotate_on_open = false)
+        : base_filename_(std::move(base_filename))
+        , max_size_(max_size)
+        , max_files_(max_files)
+    {
+        file_helper_.open(FileNameCalc::calc_filename(base_filename_, 0));
+        current_size_ = file_helper_.size(); // expensive. called only once
+        if (rotate_on_open && current_size_ > 0)
+        {
+            rotate_();
+        }
+    }
+    filename_t filename()
+    {
+        std::lock_guard<Mutex> lock(base_sink<Mutex>::mutex_);
+        return file_helper_.filename();
+    }
 
 protected:
-    void sink_it_(const details::log_msg &msg) override;
-    void flush_() override;
+    void sink_it_(const details::log_msg &msg) override
+    {
+        memory_buf_t formatted;
+        base_sink<Mutex>::formatter_->format(msg, formatted);
+        current_size_ += formatted.size();
+        if (current_size_ > max_size_)
+        {
+            rotate_();
+            current_size_ = formatted.size();
+        }
+        file_helper_.write(formatted);
+    }
+    void flush_() override
+    {
+        file_helper_.flush();
+    }
 
 private:
     // Rotate files:
@@ -36,11 +84,45 @@ private:
     // log.1.txt -> log.2.txt
     // log.2.txt -> log.3.txt
     // log.3.txt -> delete
-    void rotate_();
+    void rotate_()
+    {
+        using details::os::filename_to_str;
+        using details::os::path_exists;
+        file_helper_.close();
+        for (auto i = max_files_; i > 0; --i)
+        {
+            filename_t src = FileNameCalc::calc_filename(base_filename_, i - 1);
+            if (!path_exists(src))
+            {
+                continue;
+            }
+            filename_t target = FileNameCalc::calc_filename(base_filename_, i);
+
+            if (!rename_file_(src, target))
+            {
+                // if failed try again after a small delay.
+                // this is a workaround to a windows issue, where very high rotation
+                // rates can cause the rename to fail with permission denied (because of antivirus?).
+                details::os::sleep_for_millis(100);
+                if (!rename_file_(src, target))
+                {
+                    file_helper_.reopen(true); // truncate the log file anyway to prevent it to grow beyond its limit!
+                    current_size_ = 0;
+                    throw_spdlog_ex("rotating_file_sink: failed renaming " + filename_to_str(src) + " to " + filename_to_str(target), errno);
+                }
+            }
+        }
+        file_helper_.reopen(true);
+    }
 
     // delete the target if exists, and rename the src file  to target
     // return true on success, false otherwise.
-    bool rename_file_(const filename_t &src_filename, const filename_t &target_filename);
+    bool rename_file_(const filename_t &src_filename, const filename_t &target_filename)
+    {
+        // try to delete the target file in case it already exists.
+        (void)details::os::remove(target_filename);
+        return details::os::rename(src_filename, target_filename) == 0;
+    }
 
     filename_t base_filename_;
     std::size_t max_size_;
@@ -49,6 +131,7 @@ private:
     details::file_helper file_helper_;
 };
 
+
 using rotating_file_sink_mt = rotating_file_sink<std::mutex>;
 using rotating_file_sink_st = rotating_file_sink<details::null_mutex>;
 
@@ -72,7 +155,3 @@ inline std::shared_ptr<logger> rotating_logger_st(
     return Factory::template create<sinks::rotating_file_sink_st>(logger_name, filename, max_file_size, max_files, rotate_on_open);
 }
 } // namespace spdlog
-
-#ifdef SPDLOG_HEADER_ONLY
-#include "rotating_file_sink-inl.h"
-#endif

src/file_sinks.cpp

@@ -14,7 +14,3 @@
 
 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/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>;
\ No newline at end of file

tests/CMakeLists.txt

@@ -18,6 +18,7 @@ set(SPDLOG_UTESTS_SOURCES
     test_file_helper.cpp
     test_file_logging.cpp
     test_daily_logger.cpp
+    test_rotating_logger.cpp
     test_misc.cpp
     test_eventlog.cpp
     test_pattern_formatter.cpp

tests/test_daily_logger.cpp

@@ -61,28 +61,6 @@ TEST_CASE("daily_logger with custom calculator", "[daily_logger]")
     require_message_count(filename, 10);
 }
 
-/*
- * File name calculations
- */
-
-TEST_CASE("rotating_file_sink::calc_filename1", "[rotating_file_sink]]")
-{
-    auto filename = spdlog::sinks::rotating_file_sink_st::calc_filename("rotated.txt", 3);
-    REQUIRE(filename == "rotated.3.txt");
-}
-
-TEST_CASE("rotating_file_sink::calc_filename2", "[rotating_file_sink]]")
-{
-    auto filename = spdlog::sinks::rotating_file_sink_st::calc_filename("rotated", 3);
-    REQUIRE(filename == "rotated.3");
-}
-
-TEST_CASE("rotating_file_sink::calc_filename3", "[rotating_file_sink]]")
-{
-    auto filename = spdlog::sinks::rotating_file_sink_st::calc_filename("rotated.txt", 0);
-    REQUIRE(filename == "rotated.txt");
-}
-
 // regex supported only from gcc 4.9 and above
 #if defined(_MSC_VER) || !(__GNUC__ <= 4 && __GNUC_MINOR__ < 9)
 

tests/test_rotating_logger.cpp

+/*
+ * This content is released under the MIT License as specified in https://raw.githubusercontent.com/gabime/spdlog/master/LICENSE
+ */
+#include "includes.h"
+
+TEST_CASE("rotating_looger with default calculator", "[rotating_logger]")
+{
+    using sink_type = spdlog::sinks::rotating_file_sink<std::mutex, spdlog::sinks::rotating_filename_calculator>;
+
+    prepare_logdir();
+
+    std::string filename = "test_logs/rotating_default";
+    
+    auto logger = spdlog::create<sink_type>("logger", filename, 5 * 1024, 1);
+    for (int i = 0; i < 10; ++i)
+    {
+        logger->info("Hello World!", i);
+    }
+    logger->flush();
+
+    require_message_count(filename, 10);
+}
+
+struct custom_rotating_file_name_calculator
+{
+    static spdlog::filename_t calc_filename(const spdlog::filename_t &filename, std::size_t)
+    {
+        spdlog::filename_t basename, ext;
+        std::tie(basename, ext) = spdlog::details::file_helper::split_by_extension(filename);
+        return fmt::format(SPDLOG_FILENAME_T("{}_custom{}"), basename, ext);
+    }
+};
+
+TEST_CASE("rotating_logger with custom calculator", "[rotating_logger]")
+{
+    using sink_type = spdlog::sinks::rotating_file_sink<std::mutex, custom_rotating_file_name_calculator>;
+
+    prepare_logdir();
+
+    // calculate filename
+    std::string basename = "test_logs/rotating";
+    spdlog::memory_buf_t w;
+    fmt::format_to(w, "{}_custom", basename);
+
+    auto logger = spdlog::create<sink_type>("logger", basename, 5 * 1024, 1);
+    for (int i = 0; i < 10; ++i)
+    {
+        logger->info("Hello World!");
+    }
+
+    logger->flush();
+
+    auto filename = fmt::to_string(w);
+    require_message_count(filename, 10);
+}
+
+/*
+ * File name calculations
+ */
+
+TEST_CASE("rotating_file_sink::calc_filename1", "[rotating_file_sink]]")
+{
+    auto filename = spdlog::sinks::rotating_filename_calculator::calc_filename("rotated.txt", 3);
+    REQUIRE(filename == "rotated.3.txt");
+}
+
+TEST_CASE("rotating_file_sink::calc_filename2", "[rotating_file_sink]]")
+{
+    auto filename = spdlog::sinks::rotating_filename_calculator::calc_filename("rotated", 3);
+    REQUIRE(filename == "rotated.3");
+}
+
+TEST_CASE("rotating_file_sink::calc_filename3", "[rotating_file_sink]]")
+{
+    auto filename = spdlog::sinks::rotating_filename_calculator::calc_filename("rotated.txt", 0);
+    REQUIRE(filename == "rotated.txt");
+}