mlog: --max-log-files to set the max number of rotated log files

contrib/epee/include/misc_log_ex.h

@@ -34,6 +34,7 @@
 
 #define MONERO_DEFAULT_LOG_CATEGORY "default"
 #define MAX_LOG_FILE_SIZE 104850000 // 100 MB - 7600 bytes
+#define MAX_LOG_FILES 50
 
 #define MCFATAL(cat,x) CLOG(FATAL,cat) << x
 #define MCERROR(cat,x) CLOG(ERROR,cat) << x
@@ -105,7 +106,7 @@
 #endif
 
 std::string mlog_get_default_log_path(const char *default_filename);
-void mlog_configure(const std::string &filename_base, bool console, const std::size_t max_log_file_size = MAX_LOG_FILE_SIZE);
+void mlog_configure(const std::string &filename_base, bool console, const std::size_t max_log_file_size = MAX_LOG_FILE_SIZE, const std::size_t max_log_files = MAX_LOG_FILES);
 void mlog_set_categories(const char *categories);
 std::string mlog_get_categories();
 void mlog_set_log_level(int level);

contrib/epee/src/mlog.cpp

@@ -116,7 +116,7 @@ static const char *get_default_categories(int level)
   return categories;
 }
 
-void mlog_configure(const std::string &filename_base, bool console, const std::size_t max_log_file_size)
+void mlog_configure(const std::string &filename_base, bool console, const std::size_t max_log_file_size, const std::size_t max_log_files)
 {
   el::Configurations c;
   c.setGlobally(el::ConfigurationType::Filename, filename_base);
@@ -134,9 +134,58 @@ void mlog_configure(const std::string &filename_base, bool console, const std::s
   el::Loggers::addFlag(el::LoggingFlag::DisableApplicationAbortOnFatalLog);
   el::Loggers::addFlag(el::LoggingFlag::ColoredTerminalOutput);
   el::Loggers::addFlag(el::LoggingFlag::StrictLogFileSizeCheck);
-  el::Helpers::installPreRollOutCallback([filename_base](const char *name, size_t){
+  el::Helpers::installPreRollOutCallback([filename_base, max_log_files](const char *name, size_t){
     std::string rname = generate_log_filename(filename_base.c_str());
     rename(name, rname.c_str());
+    if (max_log_files != 0)
+    {
+      std::vector<boost::filesystem::path> found_files;
+      const boost::filesystem::directory_iterator end_itr;
+      for (boost::filesystem::directory_iterator iter(boost::filesystem::path(filename_base).parent_path()); iter != end_itr; ++iter)
+      {
+        const std::string filename = iter->path().string();
+        if (filename.size() >= filename_base.size() && std::memcmp(filename.data(), filename_base.data(), filename_base.size()) == 0)
+        {
+          found_files.push_back(iter->path());
+        }
+      }
+      if (found_files.size() >= max_log_files)
+      {
+        std::sort(found_files.begin(), found_files.end(), [](const boost::filesystem::path &a, const boost::filesystem::path &b) {
+          boost::system::error_code ec;
+          std::time_t ta = boost::filesystem::last_write_time(boost::filesystem::path(a), ec);
+          if (ec)
+          {
+            MERROR("Failed to get timestamp from " << a << ": " << ec);
+            ta = std::time(nullptr);
+          }
+          std::time_t tb = boost::filesystem::last_write_time(boost::filesystem::path(b), ec);
+          if (ec)
+          {
+            MERROR("Failed to get timestamp from " << b << ": " << ec);
+            tb = std::time(nullptr);
+          }
+          static_assert(std::is_integral<time_t>(), "bad time_t");
+          return ta < tb;
+        });
+        for (size_t i = 0; i <= found_files.size() - max_log_files; ++i)
+        {
+          try
+          {
+            boost::system::error_code ec;
+            boost::filesystem::remove(found_files[i], ec);
+            if (ec)
+            {
+              MERROR("Failed to remove " << found_files[i] << ": " << ec);
+            }
+          }
+          catch (const std::exception &e)
+          {
+            MERROR("Failed to remove " << found_files[i] << ": " << e.what());
+          }
+        }
+      }
+    }
   });
   mlog_set_common_prefix();
   const char *monero_log = getenv("MONERO_LOGS");

src/daemon/command_line_args.h

@@ -72,6 +72,11 @@ namespace daemon_args
   , "Specify maximum log file size [B]"
   , MAX_LOG_FILE_SIZE
   };
+  const command_line::arg_descriptor<std::size_t> arg_max_log_files = {
+    "max-log-files"
+  , "Specify maximum number of rotated log files to be saved (no limit by setting to 0)"
+  , MAX_LOG_FILES
+  };
   const command_line::arg_descriptor<std::string> arg_log_level = {
     "log-level"
   , ""

src/daemon/main.cpp

@@ -84,6 +84,7 @@ int main(int argc, char const * argv[])
       command_line::add_arg(core_settings, daemon_args::arg_log_file);
       command_line::add_arg(core_settings, daemon_args::arg_log_level);
       command_line::add_arg(core_settings, daemon_args::arg_max_log_file_size);
+      command_line::add_arg(core_settings, daemon_args::arg_max_log_files);
       command_line::add_arg(core_settings, daemon_args::arg_max_concurrency);
       command_line::add_arg(core_settings, daemon_args::arg_zmq_rpc_bind_ip);
       command_line::add_arg(core_settings, daemon_args::arg_zmq_rpc_bind_port);
@@ -203,7 +204,7 @@ int main(int argc, char const * argv[])
     if (!command_line::is_arg_defaulted(vm, daemon_args::arg_log_file))
       log_file_path = command_line::get_arg(vm, daemon_args::arg_log_file);
     log_file_path = bf::absolute(log_file_path, relative_path_base);
-    mlog_configure(log_file_path.string(), true, command_line::get_arg(vm, daemon_args::arg_max_log_file_size));
+    mlog_configure(log_file_path.string(), true, command_line::get_arg(vm, daemon_args::arg_max_log_file_size), command_line::get_arg(vm, daemon_args::arg_max_log_files));
 
     // Set log level
     if (!command_line::is_arg_defaulted(vm, daemon_args::arg_log_level))

src/wallet/wallet_args.cpp

@@ -101,6 +101,7 @@ namespace wallet_args
 
     const command_line::arg_descriptor<std::string> arg_log_level = {"log-level", "0-4 or categories", ""};
     const command_line::arg_descriptor<std::size_t> arg_max_log_file_size = {"max-log-file-size", "Specify maximum log file size [B]", MAX_LOG_FILE_SIZE};
+    const command_line::arg_descriptor<std::size_t> arg_max_log_files = {"max-log-files", "Specify maximum number of rotated log files to be saved (no limit by setting to 0)", MAX_LOG_FILES};
     const command_line::arg_descriptor<uint32_t> arg_max_concurrency = {"max-concurrency", wallet_args::tr("Max number of threads to use for a parallel job"), DEFAULT_MAX_CONCURRENCY};
     const command_line::arg_descriptor<std::string> arg_log_file = {"log-file", wallet_args::tr("Specify log file"), ""};
     const command_line::arg_descriptor<std::string> arg_config_file = {"config-file", wallet_args::tr("Config file"), "", true};
@@ -119,6 +120,7 @@ namespace wallet_args
     command_line::add_arg(desc_params, arg_log_file);
     command_line::add_arg(desc_params, arg_log_level);
     command_line::add_arg(desc_params, arg_max_log_file_size);
+    command_line::add_arg(desc_params, arg_max_log_files);
     command_line::add_arg(desc_params, arg_max_concurrency);
     command_line::add_arg(desc_params, arg_config_file);
 
@@ -180,7 +182,7 @@ namespace wallet_args
       log_path = command_line::get_arg(vm, arg_log_file);
     else
       log_path = mlog_get_default_log_path(default_log_name);
-    mlog_configure(log_path, log_to_console, command_line::get_arg(vm, arg_max_log_file_size));
+    mlog_configure(log_path, log_to_console, command_line::get_arg(vm, arg_max_log_file_size), command_line::get_arg(vm, arg_max_log_files));
     if (!command_line::is_arg_defaulted(vm, arg_log_level))
     {
       mlog_set_log(command_line::get_arg(vm, arg_log_level).c_str());