Automatically update an app from a remote Mercurial repository

autoupdate.py

#!/usr/bin/env python

"""
Basic app which can be updated directly from a Mercurial repository.

Copyright (C) Sarah Mount, 2011.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""


import logging
import os
import shutil
import stat
import sys
import tempfile
import traceback

from PyQt4 import QtGui, QtCore

from mercurial import commands, hg, ui, error

REPO_DIR = os.path.expanduser('~' + os.sep + '.myrepo')
URL = 'https://MYPROJECT.googlecode.com/hg/'
MYAPPLOGGER = 'WHATEVER'

__author__ = 'Sarah Mount'
__date__ = 'April 2011'
__credits__ = 'Matt Mackall, Steve Borho, Mercurial mailing list'


class AppUpdator(QtCore.QThread):
    """This class automatically updates a PyQt app from a remote
    Mercurial repository.
    """

    def __init__(self, parent=None):
        QtCore.QThread.__init__(self, parent)
        self.ui = ui.ui()
        self.logger = logging.getLogger(MYAPPLOGGER)
        self.info = lambda msg : self.logger.info(msg)
        self.debug = lambda msg : self.logger.debug(msg)        
        self.ui = ui.ui()
        self.url = 'https://open-ihm.googlecode.com/hg/'
        try:
            self.repo = hg.repository(self.ui, REPO_DIR)
        except Exception:
            self.repo = hg.repository(self.ui, REPO_DIR, create=True)
        return

    def run(self):
        # Redirect stdin and stdout to tempfiles. 
        # This fixes a Windows bug which causes a Bad File Descriptor error.
        sys.stdout = tempfile.TemporaryFile()
        sys.stderr = tempfile.TemporaryFile()
        try:
            self.pullAndMerge()
        except Exception:
            self.fail()
            return
        try:
            self.install()
        except Exception:
            self.fail()
            return
        self.emit(QtCore.SIGNAL("updateSuccess()"))
        return

    def chmod(self):
        """Fix a Windows bug which marks files / folders in REPO_DIR read-only.
        """
        if not (sys.platform == 'win32' or sys.platform == 'cygwin'):
            return
        for root, dirs, files in os.walk(REPO_DIR):
            for name in files:
                os.chmod(os.path.join(root, name), stat.S_IWRITE)
            for name in dirs:
                os.chmod(os.path.join(root, name), stat.S_IWRITE)
        return

    def fail(self):
        """Called if an error occurs.

        Take the traceback, log it and notify the MainWindow.
        """
        ty, value, tback = sys.exc_info()
        msg = ''.join(traceback.format_exception(ty, value, tback))
        self.debug(msg)
        self.updateFail(msg)
        return

    def clone(self):
        """If we don't have a copy of the open-ihm repository on disk
        clone one now.
        """
        try:
            self.chmod()
            commands.clone(self.ui, self.url, dest=REPO_DIR, insecure=True)
        except Exception:
            self.fail()
        return

    def pullAndMerge(self):
        """Run an hg pull and update.
        Overwrite all local changes by default.
        If anything goes wrong with the pull or update, clone instead.
        """
        try:
            self.chmod()
            commands.pull(self.ui, self.repo, source=self.url)
            self.chmod()
            commands.update(self.ui, self.repo, clean=True)
        except error.RepoError:
            if os.path.exists(REPO_DIR):
                shutil.rmtree(REPO_DIR)
                self.clone()
        return
    
    def install(self):
        # Use distutils or whatever to install app. 
        return

    def updateFail(self, message):
        """If checking for updates times out (for example, if there
        is no current network connection) then fail silently.
        """
        self.emit(QtCore.SIGNAL("updateFailure(QString)"), QtCore.QString(message))
        return


class MainWindow(QtGui.QMainWindow):

    def __init__(self, parent=None):
        QtGui.QMainWindow.__init__(self)
        self.menubar = QtGui.QMenuBar(self)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 800, 26))
        self.menubar.setObjectName("menubar")
        self.menuHelp = QtGui.QMenu(self.menubar)
        self.menuHelp.setObjectName("menuHelp")
        self.menuHelp.setTitle(QtGui.QApplication.translate("MainWindow", "&Help", None, QtGui.QApplication.UnicodeUTF8))
        self.menubar.addAction(self.menuHelp.menuAction())
        self.actionUpdate = QtGui.QAction(self)
        self.actionUpdate.setObjectName("actionUpdate")
        self.actionUpdate.setText(QtGui.QApplication.translate("MainWindow", "Update app", None, QtGui.QApplication.UnicodeUTF8))
        self.menuHelp.addAction(self.actionUpdate)
        QtCore.QObject.connect(self.actionUpdate, QtCore.SIGNAL("triggered()"), self.updateApp)

        self.thread = AppUpdator() # For updating software
        return
        
    def updateApp(self):
        msg = ("Software update starting. \n" +
               "Please make sure you have a working Internet connection.\n" +
               "This may take some time.")
        QtGui.QMessageBox.information(self, "Software update notice", msg)

        self.connect(self.thread, QtCore.SIGNAL("updateSuccess()"), self.updateSuccess)
        self.connect(self.thread, QtCore.SIGNAL("updateFailure(QString)"), self.updateFailed)
        self.thread.start()
        return

    def updateFailed(self, message):
        msg = ("Software update failed.\n" + str(message))
        QtGui.QMessageBox.critical(self, "Software update notice", msg)
        return

    def updateSuccess(self):
        msg = ("Software update was successful.\n" +
               "Please close open-ihm and restart for changes to take effect.")
        QtGui.QMessageBox.information(self, "Software update notice", msg)
        return

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())