# Copyright (C) 2015 Canonical Ltd.
#
# This file is part of cloud-init. See LICENSE file for license information.
"""
events for reporting.
The events here are designed to be used with reporting.
They can be published to registered handlers with report_event.
"""
import base64
import os.path
import time
from . import instantiated_handler_registry, available_handlers
FINISH_EVENT_TYPE = 'finish'
START_EVENT_TYPE = 'start'
DEFAULT_EVENT_ORIGIN = 'cloudinit'
class _nameset(set):
def __getattr__(self, name):
if name in self:
return name
raise AttributeError("%s not a valid value" % name)
status = _nameset(("SUCCESS", "WARN", "FAIL"))
class ReportingEvent(object):
"""Encapsulation of event formatting."""
def __init__(self, event_type, name, description,
origin=DEFAULT_EVENT_ORIGIN, timestamp=None):
self.event_type = event_type
self.name = name
self.description = description
self.origin = origin
if timestamp is None:
timestamp = time.time()
self.timestamp = timestamp
def as_string(self):
"""The event represented as a string."""
return '{0}: {1}: {2}'.format(
self.event_type, self.name, self.description)
def as_dict(self):
"""The event represented as a dictionary."""
return {'name': self.name, 'description': self.description,
'event_type': self.event_type, 'origin': self.origin,
'timestamp': self.timestamp}
class FinishReportingEvent(ReportingEvent):
def __init__(self, name, description, result=status.SUCCESS,
post_files=None):
super(FinishReportingEvent, self).__init__(
FINISH_EVENT_TYPE, name, description)
self.result = result
if post_files is None:
post_files = []
self.post_files = post_files
if result not in status:
raise ValueError("Invalid result: %s" % result)
def as_string(self):
return '{0}: {1}: {2}: {3}'.format(
self.event_type, self.name, self.result, self.description)
def as_dict(self):
"""The event represented as json friendly."""
data = super(FinishReportingEvent, self).as_dict()
data['result'] = self.result
if self.post_files:
data['files'] = _collect_file_info(self.post_files)
return data
def report_event(event, excluded_handler_types=None):
"""Report an event to all registered event handlers
except those whose type is in excluded_handler_types.
This should generally be called via one of the other functions in
the reporting module.
:param excluded_handler_types:
List of handlers types to exclude from reporting the event to.
:param event_type:
The type of the event; this should be a constant from the
reporting module.
"""
if not excluded_handler_types:
excluded_handler_types = {}
excluded_handler_classes = {
hndl_cls
for hndl_type, hndl_cls in available_handlers.registered_items.items()
if hndl_type in excluded_handler_types
}
handlers = instantiated_handler_registry.registered_items.items()
for _, handler in handlers:
if type(handler) in excluded_handler_classes:
continue # skip this excluded handler
handler.publish_event(event)
def report_finish_event(event_name, event_description,
result=status.SUCCESS, post_files=None):
"""Report a "finish" event.
See :py:func:`.report_event` for parameter details.
"""
event = FinishReportingEvent(event_name, event_description, result,
post_files=post_files)
return report_event(event)
def report_start_event(event_name, event_description):
"""Report a "start" event.
:param event_name:
The name of the event; this should be a topic which events would
share (e.g. it will be the same for start and finish events).
:param event_description:
A human-readable description of the event that has occurred.
"""
event = ReportingEvent(START_EVENT_TYPE, event_name, event_description)
return report_event(event)
class ReportEventStack(object):
"""Context Manager for using :py:func:`report_event`
This enables calling :py:func:`report_start_event` and
:py:func:`report_finish_event` through a context manager.
:param name:
the name of the event
:param description:
the event's description, passed on to :py:func:`report_start_event`
:param message:
the description to use for the finish event. defaults to
:param:description.
:param parent:
:type parent: :py:class:ReportEventStack or None
The parent of this event. The parent is populated with
results of all its children. The name used in reporting
is <parent.name>/<name>
:param reporting_enabled:
Indicates if reporting events should be generated.
If not provided, defaults to the parent's value, or True if no parent
is provided.
:param result_on_exception:
The result value to set if an exception is caught. default
value is FAIL.
"""
def __init__(self, name, description, message=None, parent=None,
reporting_enabled=None, result_on_exception=status.FAIL,
post_files=None):
self.parent = parent
self.name = name
self.description = description
self.message = message
self.result_on_exception = result_on_exception
self.result = status.SUCCESS
if post_files is None:
post_files = []
self.post_files = post_files
# use parents reporting value if not provided
if reporting_enabled is None:
if parent:
reporting_enabled = parent.reporting_enabled
else:
reporting_enabled = True
self.reporting_enabled = reporting_enabled
if parent:
self.fullname = '/'.join((parent.fullname, name,))
else:
self.fullname = self.name
self.children = {}
def __repr__(self):
return ("ReportEventStack(%s, %s, reporting_enabled=%s)" %
(self.name, self.description, self.reporting_enabled))
def __enter__(self):
self.result = status.SUCCESS
if self.reporting_enabled:
report_start_event(self.fullname, self.description)
if self.parent:
self.parent.children[self.name] = (None, None)
return self
def _childrens_finish_info(self):
for cand_result in (status.FAIL, status.WARN):
for _name, (value, _msg) in self.children.items():
if value == cand_result:
return (value, self.message)
return (self.result, self.message)
@property
def result(self):
return self._result
@result.setter
def result(self, value):
if value not in status:
raise ValueError("'%s' not a valid result" % value)
self._result = value
@property
def message(self):
if self._message is not None:
return self._message
return self.description
@message.setter
def message(self, value):
self._message = value
def _finish_info(self, exc):
# return tuple of description, and value
if exc:
return (self.result_on_exception, self.message)
return self._childrens_finish_info()
def __exit__(self, exc_type, exc_value, traceback):
(result, msg) = self._finish_info(exc_value)
if self.parent:
self.parent.children[self.name] = (result, msg)
if self.reporting_enabled:
report_finish_event(self.fullname, msg, result,
post_files=self.post_files)
def _collect_file_info(files):
if not files:
return None
ret = []
for fname in files:
if not os.path.isfile(fname):
content = None
else:
with open(fname, "rb") as fp:
content = base64.b64encode(fp.read()).decode()
ret.append({'path': fname, 'content': content,
'encoding': 'base64'})
return ret
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