# This file is part of cloud-init. See LICENSE file for license information. import abc import fcntl import json import logging import os import queue import struct import threading import time import uuid from datetime import datetime from threading import Event from typing import Union from cloudinit import url_helper, util from cloudinit.registry import DictRegistry LOG = logging.getLogger(__name__) class ReportException(Exception): pass class ReportingHandler(metaclass=abc.ABCMeta): """Base class for report handlers. Implement :meth:`~publish_event` for controlling what the handler does with an event. """ @abc.abstractmethod def publish_event(self, event): """Publish an event.""" def flush(self): """Ensure ReportingHandler has published all events""" class LogHandler(ReportingHandler): """Publishes events to the cloud-init log at the ``DEBUG`` log level.""" def __init__(self, level="DEBUG"): super(LogHandler, self).__init__() if isinstance(level, int): pass else: input_level = level try: level = getattr(logging, level.upper()) except Exception: LOG.warning("invalid level '%s', using WARN", input_level) level = logging.WARN self.level = level def publish_event(self, event): logger = logging.getLogger( ".".join(["cloudinit", "reporting", event.event_type, event.name]) ) logger.log(self.level, event.as_string()) class PrintHandler(ReportingHandler): """Print the event as a string.""" def publish_event(self, event): print(event.as_string()) class WebHookHandler(ReportingHandler): def __init__( self, endpoint, consumer_key=None, token_key=None, token_secret=None, consumer_secret=None, timeout=None, retries=None, ): super(WebHookHandler, self).__init__() if any([consumer_key, token_key, token_secret, consumer_secret]): oauth_helper = url_helper.OauthUrlHelper( consumer_key=consumer_key, token_key=token_key, token_secret=token_secret, consumer_secret=consumer_secret, ) self.readurl = oauth_helper.readurl else: self.readurl = url_helper.readurl self.endpoint = endpoint self.timeout = timeout self.retries = retries self.ssl_details = util.fetch_ssl_details() self.flush_requested = Event() self.queue = queue.Queue() self.event_processor = threading.Thread(target=self.process_requests) self.event_processor.daemon = True self.event_processor.start() def process_requests(self): consecutive_failed = 0 while True: if self.flush_requested.is_set() and consecutive_failed > 2: # At this point the main thread is waiting for the queue to # drain. If we have a queue of events piled up and recent # events have failed, lets not waste time trying to post # the rest, especially since a long timeout could block # cloud-init for quite a long time. LOG.warning( "Multiple consecutive failures in WebHookHandler. " "Cancelling all queued events." ) while not self.queue.empty(): self.queue.get_nowait() self.queue.task_done() consecutive_failed = 0 args = self.queue.get(block=True) try: self.readurl( args[0], data=args[1], timeout=args[2], retries=args[3], ssl_details=args[4], log_req_resp=False, ) consecutive_failed = 0 except Exception as e: LOG.warning( "Failed posting event: %s. This was caused by: %s", args[1], e, ) consecutive_failed += 1 finally: self.queue.task_done() def publish_event(self, event): event_data = event.as_dict() LOG.debug( "Queuing POST to %s, data: %s", self.endpoint, event_data, ) self.queue.put( ( self.endpoint, json.dumps(event_data), self.timeout, self.retries, self.ssl_details, ) ) def flush(self): self.flush_requested.set() LOG.debug("WebHookHandler flushing remaining events") self.queue.join() self.flush_requested.clear() class HyperVKvpReportingHandler(ReportingHandler): """ Reports events to a Hyper-V host using Key-Value-Pair exchange protocol and can be used to obtain high level diagnostic information from the host. To use this facility, the KVP user-space daemon (hv_kvp_daemon) has to be running. It reads the kvp_file when the host requests the guest to enumerate the KVP's. This reporter collates all events for a module (origin|name) in a single json string in the dictionary. For more information, see https://technet.microsoft.com/en-us/library/dn798287.aspx#Linux%20guests """ HV_KVP_EXCHANGE_MAX_VALUE_SIZE = 2048 # The maximum value size expected in Azure HV_KVP_AZURE_MAX_VALUE_SIZE = 1024 HV_KVP_EXCHANGE_MAX_KEY_SIZE = 512 HV_KVP_RECORD_SIZE = ( HV_KVP_EXCHANGE_MAX_KEY_SIZE + HV_KVP_EXCHANGE_MAX_VALUE_SIZE ) EVENT_PREFIX = "CLOUD_INIT" MSG_KEY = "msg" RESULT_KEY = "result" DESC_IDX_KEY = "msg_i" JSON_SEPARATORS = (",", ":") KVP_POOL_FILE_GUEST = "/var/lib/hyperv/.kvp_pool_1" _already_truncated_pool_file = False def __init__(self, kvp_file_path=KVP_POOL_FILE_GUEST, event_types=None): super(HyperVKvpReportingHandler, self).__init__() self._kvp_file_path = kvp_file_path HyperVKvpReportingHandler._truncate_guest_pool_file( self._kvp_file_path ) self._event_types = event_types self.q = queue.Queue() self.incarnation_no = self._get_incarnation_no() self.event_key_prefix = "{0}|{1}".format( self.EVENT_PREFIX, self.incarnation_no ) self.publish_thread = threading.Thread( target=self._publish_event_routine ) self.publish_thread.daemon = True self.publish_thread.start() @classmethod def _truncate_guest_pool_file(cls, kvp_file): """ Truncate the pool file if it has not been truncated since boot. This should be done exactly once for the file indicated by KVP_POOL_FILE_GUEST constant above. This method takes a filename so that we can use an arbitrary file during unit testing. Since KVP is a best-effort telemetry channel we only attempt to truncate the file once and only if the file has not been modified since boot. Additional truncation can lead to loss of existing KVPs. """ if cls._already_truncated_pool_file: return boot_time = time.time() - float(util.uptime()) try: if os.path.getmtime(kvp_file) < boot_time: with open(kvp_file, "w"): pass except (OSError, IOError) as e: LOG.warning("failed to truncate kvp pool file, %s", e) finally: cls._already_truncated_pool_file = True def _get_incarnation_no(self): """ use the time passed as the incarnation number. the incarnation number is the number which are used to distinguish the old data stored in kvp and the new data. """ uptime_str = util.uptime() try: return int(time.time() - float(uptime_str)) except ValueError: LOG.warning("uptime '%s' not in correct format.", uptime_str) return 0 def _iterate_kvps(self, offset): """iterate the kvp file from the current offset.""" with open(self._kvp_file_path, "rb") as f: fcntl.flock(f, fcntl.LOCK_EX) f.seek(offset) record_data = f.read(self.HV_KVP_RECORD_SIZE) while len(record_data) == self.HV_KVP_RECORD_SIZE: kvp_item = self._decode_kvp_item(record_data) yield kvp_item record_data = f.read(self.HV_KVP_RECORD_SIZE) fcntl.flock(f, fcntl.LOCK_UN) def _event_key(self, event): """ the event key format is: CLOUD_INIT|||| [|subevent_index] """ return "{0}|{1}|{2}|{3}".format( self.event_key_prefix, event.event_type, event.name, uuid.uuid4() ) def _encode_kvp_item(self, key, value): data = struct.pack( "%ds%ds" % ( self.HV_KVP_EXCHANGE_MAX_KEY_SIZE, self.HV_KVP_EXCHANGE_MAX_VALUE_SIZE, ), key.encode("utf-8"), value.encode("utf-8"), ) return data def _decode_kvp_item(self, record_data): record_data_len = len(record_data) if record_data_len != self.HV_KVP_RECORD_SIZE: raise ReportException( "record_data len not correct {0} {1}.".format( record_data_len, self.HV_KVP_RECORD_SIZE ) ) k = ( record_data[0 : self.HV_KVP_EXCHANGE_MAX_KEY_SIZE] .decode("utf-8") .strip("\x00") ) v = ( record_data[ self.HV_KVP_EXCHANGE_MAX_KEY_SIZE : self.HV_KVP_RECORD_SIZE ] .decode("utf-8") .strip("\x00") ) return {"key": k, "value": v} def _append_kvp_item(self, record_data): with open(self._kvp_file_path, "ab") as f: fcntl.flock(f, fcntl.LOCK_EX) for data in record_data: f.write(data) f.flush() fcntl.flock(f, fcntl.LOCK_UN) def _break_down(self, key, meta_data, description): del meta_data[self.MSG_KEY] des_in_json = json.dumps(description) des_in_json = des_in_json[1 : (len(des_in_json) - 1)] i = 0 result_array = [] message_place_holder = '"' + self.MSG_KEY + '":""' while True: meta_data[self.DESC_IDX_KEY] = i meta_data[self.MSG_KEY] = "" data_without_desc = json.dumps( meta_data, separators=self.JSON_SEPARATORS ) room_for_desc = ( self.HV_KVP_AZURE_MAX_VALUE_SIZE - len(data_without_desc) - 8 ) value = data_without_desc.replace( message_place_holder, '"{key}":"{desc}"'.format( key=self.MSG_KEY, desc=des_in_json[:room_for_desc] ), ) subkey = "{}|{}".format(key, i) result_array.append(self._encode_kvp_item(subkey, value)) i += 1 des_in_json = des_in_json[room_for_desc:] if len(des_in_json) == 0: break return result_array def write_key(self, key: str, value: str) -> None: """Write KVP key-value. Values will be truncated as needed. """ if len(value) >= self.HV_KVP_AZURE_MAX_VALUE_SIZE: value = value[0 : self.HV_KVP_AZURE_MAX_VALUE_SIZE - 1] data = [self._encode_kvp_item(key, value)] try: self._append_kvp_item(data) except (OSError, IOError): LOG.warning("failed posting kvp=%s value=%s", key, value) def _encode_event(self, event): """ encode the event into kvp data bytes. if the event content reaches the maximum length of kvp value. then it would be cut to multiple slices. """ key = self._event_key(event) meta_data = { "name": event.name, "type": event.event_type, "ts": ( datetime.utcfromtimestamp(event.timestamp).isoformat() + "Z" ), } if hasattr(event, self.RESULT_KEY): meta_data[self.RESULT_KEY] = event.result meta_data[self.MSG_KEY] = event.description value = json.dumps(meta_data, separators=self.JSON_SEPARATORS) # if it reaches the maximum length of kvp value, # break it down to slices. # this should be very corner case. if len(value) > self.HV_KVP_AZURE_MAX_VALUE_SIZE: return self._break_down(key, meta_data, event.description) else: data = self._encode_kvp_item(key, value) return [data] def _publish_event_routine(self): while True: items_from_queue = 0 try: event = self.q.get(block=True) items_from_queue += 1 encoded_data = [] while event is not None: encoded_data += self._encode_event(event) try: # get all the rest of the events in the queue event = self.q.get(block=False) items_from_queue += 1 except queue.Empty: event = None try: self._append_kvp_item(encoded_data) except (OSError, IOError) as e: LOG.warning("failed posting events to kvp, %s", e) finally: for _ in range(items_from_queue): self.q.task_done() # when main process exits, q.get() will through EOFError # indicating we should exit this thread. except EOFError: return # since the saving to the kvp pool can be a time costing task # if the kvp pool already contains a chunk of data, # so defer it to another thread. def publish_event(self, event): if not self._event_types or event.event_type in self._event_types: self.q.put(event) def flush(self): LOG.debug("HyperVReportingHandler flushing remaining events") self.q.join() # Type[ReportingHandler] doesn't work here because each class has different # call args. Protocols in python 3.8 can probably make this simpler. HandlerType = Union[ ReportingHandler, LogHandler, PrintHandler, WebHookHandler, HyperVKvpReportingHandler, ] available_handlers = DictRegistry() available_handlers.register_item("log", LogHandler) available_handlers.register_item("print", PrintHandler) available_handlers.register_item("webhook", WebHookHandler) available_handlers.register_item("hyperv", HyperVKvpReportingHandler)