added log rotate

lib/ApplicationFeatures/LoggerFeature.cpp

@@ -42,6 +42,7 @@ LoggerFeature::LoggerFeature(application_features::ApplicationServer* server)
       _lineNumber(false),
       _thread(false),
       _performance(false),
+      _keepLogRotate(false),
       _daemon(false),
       _backgrounded(false),
       _threaded(false) {
@@ -92,6 +93,10 @@ void LoggerFeature::collectOptions(std::shared_ptr<ProgramOptions> options) {
   options->addHiddenOption("--log.performance",
                            "shortcut for '--log.level requests=trace'",
                            new BooleanParameter(&_performance));
+
+  options->addHiddenOption("--log.keep-logrotate",
+                           "keep the old log file after receiving a sighup",
+                           new BooleanParameter(&_keepLogRotate));
 }
 
 void LoggerFeature::loadOptions(
@@ -138,6 +143,7 @@ void LoggerFeature::prepare() {
   Logger::setShowLineNumber(_lineNumber);
   Logger::setShowThreadIdentifier(_thread);
   Logger::setOutputPrefix(_prefix);
+  Logger::setKeepLogrotate(_keepLogRotate);
 
   for (auto definition : _output) {
     if (_daemon && StringUtils::isPrefix(definition, "file://")) {

lib/ApplicationFeatures/LoggerFeature.h

@@ -47,6 +47,7 @@ class LoggerFeature final : public application_features::ApplicationFeature {
   bool _lineNumber;
   bool _thread;
   bool _performance;
+  bool _keepLogRotate;
 
  private:
   bool _daemon;

lib/Logger/LogAppenderFile.cpp

@@ -27,6 +27,7 @@
 
 #include "Basics/Exceptions.h"
 #include "Basics/FileUtils.h"
+#include "Logger/Logger.h"
 
 using namespace arangodb;
 using namespace arangodb::basics;
@@ -60,10 +61,14 @@ void LogAppenderFile::reopen() {
                         S_IRUSR | S_IWUSR | S_IRGRP);
 
     if (fd < 0) {
-      TRI_RenameFile(backup.c_str(), filename.c_str());
+      FileUtils::rename(backup, filename);
       continue;
     }
 
+    if (!Logger::_keepLogRotate) {
+      FileUtils::remove(backup);
+    }
+
     _fds[pos].first = fd;
 
     if (old > STDERR_FILENO) {

lib/Logger/Logger.cpp

@@ -44,6 +44,7 @@ bool Logger::_showLineNumber(false);
 bool Logger::_showThreadIdentifier(false);
 bool Logger::_threaded(false);
 bool Logger::_useLocalTime(false);
+bool Logger::_keepLogRotate(false);
 std::string Logger::_outputPrefix("");
 
 std::unique_ptr<LogThread> Logger::_loggingThread(nullptr);
@@ -169,6 +170,16 @@ void Logger::setUseLocalTime(bool show) {
   _useLocalTime = show;
 }
 
+// NOTE: this function should not be called if the logging is active.
+void Logger::setKeepLogrotate(bool keep) {
+  if (_active) {
+    THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL,
+                                   "cannot change keep log rotate if logging is active");
+  }
+
+  _keepLogRotate = keep;
+}
+
 std::string const& Logger::translateLogLevel(LogLevel level) {
   static std::string DEFAULT = "DEFAULT";
   static std::string FATAL = "FATAL";

lib/Logger/Logger.h

@@ -124,6 +124,7 @@ class Logger {
 
   friend class LoggerStream;
   friend class LogThread;
+  friend class LogAppenderFile;
 
  public:
   static LogTopic COLLECTOR;
@@ -180,6 +181,7 @@ class Logger {
   static void setShowLineNumber(bool);
   static void setShowThreadIdentifier(bool);
   static void setUseLocalTime(bool);
+  static void setKeepLogrotate(bool);
 
   static std::string const& translateLogLevel(LogLevel);
 
@@ -213,6 +215,7 @@ class Logger {
   static bool _showThreadIdentifier;
   static bool _threaded;
   static bool _useLocalTime;
+  static bool _keepLogRotate;
   static std::string _outputPrefix;
 
   static std::unique_ptr<LogThread> _loggingThread;

lib/Logger/X

@@ -0,0 +1,22 @@
+  // helper function to prevent duplicate output filenames
+  auto hasAppender = [&existingAppenders](std::string const& filename) {
+    if (existingAppenders.find(filename) != existingAppenders.end()) {
+      return true;
+    }
+    // treat stderr and stdout as one output filename
+    if (filename == "-" &&
+        existingAppenders.find("+") != existingAppenders.end()) {
+      return true;
+    }
+    if (filename == "+" &&
+        existingAppenders.find("-") != existingAppenders.end()) {
+      return true;
+    }
+    return false;
+  };
+
+  if (hasAppender(filename)) {
+    // already have an appender for the same output
+    return nullptr;
+  }
+