Set log location at '/var/log/multibootusb.log' and show that info before installation of a distro commences.

Use 'RotatingFileHandler' instead of 'os.remove()' to rotate log because trying to remove file without closing the open handle causes exception on Windows.
Move a handleful of funtions from gen.py to osdriver.py to avoid cyclic dependency.

scripts/gen.py

@@ -18,71 +18,13 @@ import re
 import ctypes
 
 from . import config
+from .osdriver import get_physical_disk_number, wmi_get_drive_info, \
+      log, resource_path
 
 def scripts_dir_path():
     return os.path.dirname(os.path.realpath(__file__))
 
 
-def log(message, info=True, error=False, debug=False, _print=True):
-    """
-    Dirty function to log messages to file and also print on screen.
-    :param message:
-    :param info:
-    :param error:
-    :param debug:
-    :return:
-    """
-    # LOG_FILE_PATH = os.path.join(multibootusb_host_dir(), 'multibootusb.log')
-    LOG_FILE_PATH = mbusb_log_file()
-    if os.path.exists(LOG_FILE_PATH):
-        log_file_size = os.path.getsize(LOG_FILE_PATH) / (1024.0 * 1024.0)
-        if log_file_size > 1:
-            print('Removing log file as it crosses beyond 1mb')
-            os.remove(LOG_FILE_PATH)
-    logging.basicConfig(filename=LOG_FILE_PATH,
-                        filemode='a',
-                        format='%(asctime)s.%(msecs)03d %(name)s %(levelname)s %(message)s',
-                        datefmt='%H:%M:%S',
-                        level=logging.DEBUG)
-    if _print is True:
-        print(message)
-
-    # remove ANSI color codes from logs
-    # message_clean = re.compile(r'\x1b[^m]*m').sub('', message)
-
-    if info is True:
-        logging.info(message)
-    elif error is not False:
-        logging.error(message)
-    elif debug is not False:
-        logging.debug(message)
-
-
-
-def resource_path(relativePath):
-    """
-    Function to detect the correct path of file when working with sourcecode/install or binary.
-    :param relativePath: Path to file/data.
-    :return: Modified path to file/data.
-    """
-    # This is not strictly needed because Windows recognize '/'
-    # as a path separator but we follow the discipline here.
-    relativePath = relativePath.replace('/', os.sep)
-    for dir_ in [
-            os.path.abspath('.'),
-            os.path.abspath('..'),
-            getattr(sys, '_MEIPASS', None),
-            os.path.dirname(os.path.dirname( # go up two levels
-                os.path.realpath(__file__))),
-            '/usr/share/multibootusb'.replace('/', os.sep),
-            ]:
-        if dir_ is None:
-            continue
-        fullpath = os.path.join(dir_, relativePath)
-        if os.path.exists(fullpath):
-            return fullpath
-    log("Could not find resource '%s'." % relativePath)
-
 def print_version():
     """
     Simple log the version number of the multibootusb application
@@ -129,23 +71,6 @@ def sys_64bits():
     return sys.maxsize > 2**32
 
 
-def mbusb_log_file():
-    """
-    Function to genrate path to log file.
-    Under linux path is created as /tmp/multibootusb.log
-    Under Windows the file is created under installation directory
-    """
-    if platform.system() == "Linux":
-        # home_dir = os.path.expanduser('~')
-        # log_file = os.path.join(home_dir, "multibootusb.log")
-        log_file = os.path.join(tempfile.gettempdir(), "multibootusb.log")
-    elif platform.system() == "Windows":
-        # log_file = os.path.join(tempfile.gettempdir(), "multibootusb", "multibootusb.log")
-        log_file = os.path.join("multibootusb.log")
-
-    return log_file
-
-
 def multibootusb_host_dir():
     """
     Cross platform way to detect multibootusb directory on host system.
@@ -486,28 +411,7 @@ class MemoryCheck():
         """
         totalMemory = os.popen("free -m").readlines()[1].split()[1]
         return int(totalMemory)
-
-def wmi_get_drive_info(usb_disk):
-    assert platform.system() == 'Windows'
-    import wmi
-    c = wmi.WMI()
-    for partition in c.Win32_DiskPartition():
-        logical_disks = partition.associators("Win32_LogicalDiskToPartition")
-        # Here, 'disk' is a windows logical drive rather than a physical drive
-        for disk in logical_disks:
-            if disk.Caption == usb_disk:
-                return (partition, disk)
-    raise RuntimeError('Failed to obtain drive information ' + usb_disk)
     
-def get_physical_disk_number(usb_disk):
-    """
-    Get the physical disk number as detected ny Windows.
-    :param usb_disk: USB disk (Like F:)
-    :return: Disk number.
-    """
-    partition, logical_disk = wmi_get_drive_info(usb_disk)
-    log("Physical Device Number is %d" % partition.DiskIndex)
-    return partition.DiskIndex
 
 if __name__ == '__main__':
     log(quote("""Test-string"""))

scripts/mbusb_gui.py

@@ -36,6 +36,7 @@ from . import persistence
 from . import config
 from . import admin
 from . import qemu
+from . import osdriver
 from .update_cfg_file import update_distro_cfg_files
 import scripts.gui.resources
 
@@ -685,9 +686,11 @@ Selected USB disk: %s
 USB mount point: %s
 Selected distro: %s
 
-Proceed with installation?'''.lstrip() % \
-	(config.usb_disk, config.usb_mount, iso_name(config.image_path))
+Log location: %s
 
+Proceed with installation?'''.lstrip() % \
+	(config.usb_disk, config.usb_mount, iso_name(config.image_path),
+	 osdriver.mbusb_log_file())
 		reply = QtWidgets.QMessageBox.question(
 			self, 'Review selection...', msg)
 		if reply == QtWidgets.QMessageBox.Yes:

scripts/osdriver.py

@@ -1,8 +1,80 @@
+import logging
+import logging.handlers
 import os
 import platform
 import subprocess
+import sys
+
+
+def log(message, info=True, error=False, debug=False, _print=True):
+    """
+    Dirty function to log messages to file and also print on screen.
+    :param message:
+    :param info:
+    :param error:
+    :param debug:
+    :return:
+    """
+    if _print is True:
+        print(message)
+
+    # remove ANSI color codes from logs
+    # message_clean = re.compile(r'\x1b[^m]*m').sub('', message)
+
+    if info is True:
+        logging.info(message)
+    elif error is not False:
+        logging.error(message)
+    elif debug is not False:
+        logging.debug(message)
+
+def resource_path(relativePath):
+    """
+    Function to detect the correct path of file when working with sourcecode/install or binary.
+    :param relativePath: Path to file/data.
+    :return: Modified path to file/data.
+    """
+    # This is not strictly needed because Windows recognize '/'
+    # as a path separator but we follow the discipline here.
+    relativePath = relativePath.replace('/', os.sep)
+    for dir_ in [
+            os.path.abspath('.'),
+            os.path.abspath('..'),
+            getattr(sys, '_MEIPASS', None),
+            os.path.dirname(os.path.dirname( # go up two levels
+                os.path.realpath(__file__))),
+            '/usr/share/multibootusb'.replace('/', os.sep),
+            ]:
+        if dir_ is None:
+            continue
+        fullpath = os.path.join(dir_, relativePath)
+        if os.path.exists(fullpath):
+            return fullpath
+    log("Could not find resource '%s'." % relativePath)
+
+def get_physical_disk_number(usb_disk):
+    """
+    Get the physical disk number as detected ny Windows.
+    :param usb_disk: USB disk (Like F:)
+    :return: Disk number.
+    """
+    partition, logical_disk = wmi_get_drive_info(usb_disk)
+    log("Physical Device Number is %d" % partition.DiskIndex)
+    return partition.DiskIndex
+
+def wmi_get_drive_info(usb_disk):
+    assert platform.system() == 'Windows'
+    import wmi
+    c = wmi.WMI()
+    for partition in c.Win32_DiskPartition():
+        logical_disks = partition.associators("Win32_LogicalDiskToPartition")
+        # Here, 'disk' is a windows logical drive rather than a physical drive
+        for disk in logical_disks:
+            if disk.Caption == usb_disk:
+                return (partition, disk)
+    raise RuntimeError('Failed to obtain drive information ' + usb_disk)
+
 
-from .gen import get_physical_disk_number, log, resource_path
 
 class Base:
 
@@ -25,7 +97,10 @@ class Windows(Base):
 
     def physical_disk(self, usb_disk):
         return r'\\.\physicaldrive%d' % get_physical_disk_number(usb_disk)
-    
+
+    def mbusb_log_file(self):
+        return os.path.join(os.getcwd(), 'multibootusb.log')
+
 class Linux(Base):
 
     def __init__(self):
@@ -37,6 +112,10 @@ class Linux(Base):
     def physical_disk(self, usb_disk):
         return usb_disk.rstrip('0123456789')
 
+    def mbusb_log_file(self):
+        return '/var/log/multibootusb.log'
+
+
 driverClass = {
     'Windows' : Windows,
     'Linux'   : Linux,
@@ -48,6 +127,15 @@ osdriver = driverClass()
 for func_name in [
         'run_dd',
         'physical_disk',
+        'mbusb_log_file',
         ]:
     globals()[func_name] = getattr(osdriver, func_name)
- 
+
+
+logging.root.setLevel(logging.DEBUG)
+fmt = '%(asctime)s.%(msecs)03d %(name)s %(levelname)s %(message)s'
+datefmt = '%H:%M:%S'
+the_handler = logging.handlers.RotatingFileHandler(
+    osdriver.mbusb_log_file(), 'a', 1024*1024, 5)
+the_handler.setFormatter(logging.Formatter(fmt, datefmt))
+logging.root.addHandler(the_handler)