class LogInfo(QAbstractItemModel):
"""
Class for monitoring system log files.
When model is instantiated and path to system log
is set through setLogFile(), lineAdded signal is
emitted when new line is appended to the
monitored file
"""
lineAdded = Signal(str)
def __init__(self, parent=None):
super(LogInfo, self).__init__(parent)
self._f = None
self._path = None
def setLogFile(self, pathToFile):
self._path = pathToFile
if self._f is not None:
self._f.close()
self._f = open(self._path, 'r')
self.watcher = QFileSystemWatcher()
self.watcher.addPath(self._path)
self.watcher.fileChanged.connect(self._readNewLines)
def readLastLines(self, maxNumOflines=10):
if self._f is None:
raise RuntimeError("No path to log file has been set")
maxOffset = 1024 * maxNumOflines
if os.path.getsize(self._path) <= maxOffset:
return self._f.read()
else:
self._f.seek(-maxOffset, os.SEEK_END)
lines = self._f.readlines()
if len(lines) > maxNumOflines:
return lines[-maxNumOflines:]
else:
return lines
def _readNewLines(self, path):
newLines = self._f.read().splitlines()
for line in newLines:
self.lineAdded.emit(line)
def setLogFile(self, pathToFile):
self._path = pathToFile
if self._f is not None:
self._f.close()
self._f = open(self._path, 'r')
self.watcher = QFileSystemWatcher()
self.watcher.addPath(self._path)
self.watcher.fileChanged.connect(self._readNewLines)