class MessageBus:
"""
MessageBus is the heart of the backend messaging system.
Almost all communication between components goes through this MessageBus.
Components communicate with Messages, which are delivered to
MessageHandlers
via MessageBus. MessageBus knows which MessageHandlers are interested in
which type of Messages. MessageBus is also aware of MessageHandler
priorities and this way can serve high priority components first.
When MessageHandler is registered to the MessageBus there is also another
parameter besides handler itself. Second parameter is a dictionary that
defines MessageTypes that registered handler wants to be notified of and
also priorities for those message types."""
# This determines number of message types avaialble. In other words, this
# variable tells how many variables is defined in MessageType class.
NUMBER_OF_MESSAGE_TYPES = len(
[k for k, v in vars(MessageType).items() if type(v) is int]
)
def __init__(self):
"""
Create a new MessageBus object.
"""
# MessageHandlers - index is MessageType and data is a list of
# tuples (priority, MessageHandler object) that is sorted by
# priorities.
#XXX: rockstar - WTF?! Why is there a list comprehension being used
# and still only returning an empty list?
# pylint: disable-msg=W0612
self.message_handlers = [
[] for i in range(self.NUMBER_OF_MESSAGE_TYPES)
]
self.lock = threading.Lock()
self.logger = Logger().getLogger('backend.core.MessageBus')
def registerMessageHandler(self, message_handler, message_priority_list):
"""
Register a new MessageHandler to this MessageBus
@param message_handler: MessageHandler object
@param message_priority_list: Priority list for this MessageHandler
"""
if isinstance(message_handler, MessageHandler):
for key in message_priority_list:
rule = (message_priority_list[key], message_handler)
self.message_handlers[key].append(rule)
self.message_handlers[key].sort() # Keep priority order
else:
self.logger.critical(
"MessageHandler registration failed. Object " +
repr(message_handler) +" is invalid type.")
raise TypeError("Only MessageHandlers can be registered!")
self.logger.debug("MessageHandler '" + str(message_handler) +
"' registered to the message bus.")
def unregisterMessageHandler(self, message_handler):
"""
Unregister MessageHandler form this MessageBus.
@param message_handler: MessageHandler object that should be removed
from bus
"""
if isinstance(message_handler, MessageHandler):
for i in range(self.NUMBER_OF_MESSAGE_TYPES):
if len(self.message_handlers[i]) != 0:
rules = self.message_handlers[i]
for element in rules:
if element[1] is message_handler:
del element
else:
raise TypeError("Only MessageHandlers can be unregistered!")
self.logger.debug("MessageHandler '" + str(message_handler) +
"' unregistered from the message bus.")
def notifyMessage(self, message):
"""
Emit a new Message to this MessageBus.
@param message: Message object
"""
if isinstance(message, Message):
self.lock.acquire() # Lock messagebus
self.logger.debug("Message bus locked. Message of type '" +
str(message.get_type()) + "' is on the bus.")
handler_list = self.message_handlers[message.get_type()]
for element in handler_list:
element[1].handleMessage(message)
self.lock.release() # Release messagebus lock
else:
message = "TypeError occured when message was notified to the bus."
self.logger.error(message)
exmessage = "Notified message must be instances of 'Message' type"
raise TypeError(exmessage)
class LogViewer:
"""
Implements dialog that allows user to see logged events.
This dialog is used to check Entertainer logfiles. It reads all data from
selected file and saves rows to self.log_rows. Then it filters unwanted
rows away by calling self.filterMessages(). This method adds rows to
ListStore, which is the model of TreeView object.
Combobox and refresh -button actions read files again
Checkbox actions just filter current rows again
"""
UI_DIR = os.path.join(os.path.dirname(__file__), "uis")
# Is this dialog running as a stand alone process
__STAND_ALONE = None
widgets = None
dialog = None
log_store = None
log_rows = []
def __init__(self, stand_alone):
self.logfile_entertainer = Configuration().LOG
self.logger = Logger().getLogger('utils.log_viewer')
self.__STAND_ALONE = stand_alone
try:
uifile = os.path.join(self.UI_DIR, "log_dialog.ui")
self.builder = gtk.Builder()
self.builder.set_translation_domain('entertainer')
self.builder.add_from_file(uifile)
except RuntimeError:
self.logger.critical("Couldn't open ui file: " + uifile)
sys.exit(1)
callback_dic = {
"on_close_log_button_clicked" : self.on_close_log_button_clicked,
"on_log_refresh_button_clicked" : self.update_log_rows,
"on_checkbutton_debug_toggled" : self.filter_messages,
"on_checkbutton_critical_toggled" : self.filter_messages,
"on_checkbutton_error_toggled" : self.filter_messages,
"on_checkbutton_warning_toggled" : self.filter_messages,
"on_checkbutton_info_toggled" : self.filter_messages }
self.builder.connect_signals(callback_dic)
# Create log treeview
treeview = self.builder.get_object("treeview_log")
cell_renderer1 = gtk.CellRendererText()
cell_renderer2 = gtk.CellRendererText()
cell_renderer3 = gtk.CellRendererText()
cell_renderer4 = gtk.CellRendererText()
column1 = gtk.TreeViewColumn("Date")
column1.pack_start(cell_renderer1, True)
column1.set_attributes(cell_renderer1, text = 0)
column2 = gtk.TreeViewColumn("Time")
column2.pack_start(cell_renderer2, True)
column2.set_attributes(cell_renderer2, text = 1)
column3 = gtk.TreeViewColumn("Type")
column3.pack_start(cell_renderer3, True)
column3.set_attributes(cell_renderer3, text = 2)
column4 = gtk.TreeViewColumn("Message")
column4.pack_end(cell_renderer4, True)
column4.set_attributes(cell_renderer4, text = 3)
treeview.append_column(column1)
treeview.append_column(column2)
treeview.append_column(column3)
treeview.append_column(column4)
treeview.set_headers_visible(True)
# Set model to view and read data from logfile
self.log_store = gtk.ListStore(str, str, str, str)
treeview.set_model(self.log_store)
self.update_log_rows()
# Show Log viewer dialog
self.dialog = self.builder.get_object("LogDialog")
self.dialog.resize(750, 500)
self.dialog.connect("destroy", self.on_close_log_button_clicked)
self.dialog.show()
def update_log_rows(self, widget=None):
"""Read logfile and udpate treeview"""
self.log_rows[:] = []
try:
for line in open(self.logfile_entertainer, 'r'):
try:
line_table = line.split()
message = ' '.join(line_table[3:])
row = line_table[:3] + [message]
parsed_row = parse_row(row)
self.log_rows.append(parsed_row)
except IndexError:
print "Cannot parse log line: ", line
except IOError:
print "Cannot find logfile: ", self.logfile_entertainer
# Reverse so that the latest message is at top
self.log_rows.reverse()
# Filter unwated message types
self.filter_messages()
def filter_messages(self, widget = None):
"""Checks which message types should be displayed on treeview"""
if self.log_store:
self.log_store.clear()
debug = self.builder.get_object("checkbutton_debug").get_active()
critical = self.builder.get_object("checkbutton_critical").get_active()
error = self.builder.get_object("checkbutton_error").get_active()
warning = self.builder.get_object("checkbutton_warning").get_active()
info = self.builder.get_object("checkbutton_info").get_active()
for element in self.log_rows:
if element[2] == "DEBUG" and debug:
self.log_store.append(element)
elif element[2] == "CRITICAL" and critical:
self.log_store.append(element)
elif element[2] == "ERROR" and error:
self.log_store.append(element)
elif element[2] == "WARNING" and warning:
self.log_store.append(element)
elif element[2] == "INFO" and info:
self.log_store.append(element)
# Signal handlers
def on_close_log_button_clicked(self, widget):
"""
If running as a stand alone process, quit.
Otherwise only destroy dialog.
"""
self.dialog.hide()
self.dialog.destroy()
if(self.__STAND_ALONE):
gtk.main_quit()
