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# -*- coding: utf-8 -*-
# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2021 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT
"""
This module contains RequestProcessor class
"""
import logging
import sys
import time
import traceback
from datetime import datetime, timedelta, timezone
from threading import Thread, RLock, current_thread
from typing import Callable, Any
from .autotracer import AutoTracer
from .common import Common
from .decision_maker import DecisionMaker
from .stat_sender import StatisticsSender
from ..db import session_scope, setup_database, RequestResult, cleanup_old_data, restore_database, is_malformed_database
from ..internal.exceptions import SSAError
from ..internal.utils import (
singleton,
url_split,
switch_schedstats
)
@singleton
class RequestProcessor(Common):
"""
SSA Request processor implementation.
Only one instance is allowed to be created
"""
BUFFER_SIZE = 100
def __init__(self, engine=None):
super().__init__()
self.logger = logging.getLogger('req_processor')
self.logger.info('Processor enabled: %s', __package__)
# enable throttling detection kernel mechanism on service start
switch_schedstats(enabled=True)
self.engine = engine if engine else setup_database()
self._lock = RLock()
self.decision_maker = DecisionMaker(engine=engine)
self.sender = StatisticsSender()
self.auto_tracer = AutoTracer(engine=engine)
self.start_background_routine()
# sqlite is not thread-safe and saving results one-by-one
# into database slowes ssa 10x times
# so let's make a buffer that will contain some elements
# and flush it periodically
self._buffer = []
@property
def configured_duration(self):
"""
Return config file value multiplied by 1000000,
as we receive duration in microseconds
"""
return self.requests_duration * 1000000
def send_stats(self, report: dict):
"""
Call Statistics Sender
"""
try:
self.sender.send(report)
except SSAError as e:
self.logger.error('StatisticsSender failed: %s', str(e))
def start_background_routine(self) -> None:
"""
Start dumper|DecisionMaker thread in background
"""
t = Thread(target=self.background_routine, daemon=True)
t.start()
self.logger.info('[%s] Routine started', t.name)
def background_routine(self) -> None:
"""
Dumps collected stats to file once an hour.
Runs DecisionMaker once a day
Cleanup storage after DecisionMaker run
"""
while True:
tick = datetime.now(timezone.utc)
if tick.minute == 0:
if tick.hour == 0:
if is_malformed_database(self.engine):
self._save_exec(self.restore_db_with_lock(self.engine))
self.logger.info(
'[%s] Routine thread found Database disk image is malformed and now restored (%s)',
current_thread().name, tick)
self.logger.info(
'[%s] Routine thread launching buffer flushing (%s)',
current_thread().name, tick)
self._safe_exec(self.flush_with_lock)
self.logger.info(
'[%s] Routine thread launching AutoTracer (%s)',
current_thread().name, tick)
self._safe_exec(self.auto_tracer)
self.logger.info(
'[%s] Routine thread launching DecisionMaker (%s)',
current_thread().name, tick)
report = self._safe_exec(self.decision_maker)
self.logger.info(
'[%s] Routine thread launching cleanup (%s)',
current_thread().name, tick)
cleanup_old_data(self.engine)
self._safe_exec(self.send_stats, report)
# attempt to enable throttling detection kernel mechanism
# in case it was accidentally switched off
switch_schedstats(enabled=True)
self._simple_sleep(60)
else:
self._sleep_till_next_hour(tick.minute)
def _safe_exec(self, action: Callable, *args) -> Any:
"""Call requested Callable with given args and capture any exception"""
try:
return action(*args)
except Exception:
et, ev, _ = sys.exc_info()
self.logger.exception('%s failed with exception %s, %s',
str(action), et, ev,
extra={'orig_traceback': traceback.format_exc()})
def _simple_sleep(self, to_sleep: int = 15 * 60):
"""
Log and sleep given number of seconds or 15 minutes by default
"""
self.logger.info('[%s] Routine thread sleeping for (%s)',
current_thread().name, to_sleep)
time.sleep(to_sleep)
def _sleep_till_next_hour(self, start_minute):
"""
Sleep the number of minutes remaining till next hour
"""
sleep_for = (timedelta(hours=1) - timedelta(
minutes=start_minute)).total_seconds()
self._simple_sleep(int(sleep_for))
def restore_db_with_lock(self, engine):
with self._lock:
restore_database(engine)
@staticmethod
def get_interval_for(timestamp: int) -> int:
"""
Takes an hour of a day, to which the given timestamp belongs
"""
return datetime.fromtimestamp(timestamp, timezone.utc).hour
def flush_with_lock(self):
with self._lock:
objects = self._buffer[:]
self._buffer = []
self.flush_buffer(objects)
def flush_buffer(self, objects=None):
"""
Save in-memory buffer into database.
"""
if objects is None:
objects = self._buffer
if not objects:
return
with session_scope(self.engine) as db:
db.bulk_save_objects(objects)
def handle(self, data: dict) -> None:
"""
Process given request data
"""
if not data:
self.logger.info('[%s] has empty request, skipping', current_thread().name)
return
url = data.get('url')
if self.is_ignored(url):
self.logger.debug('%s ignored', url)
return
domain, uri = url_split(url)
self.logger.debug('[%s] Acquires lock to handle request counters',
current_thread().name)
objects_per_thread = []
with self._lock:
self._buffer.append(
RequestResult(
domain=domain,
path=url,
timestamp=data['timestamp'],
duration=data['duration'],
is_slow_request=data['duration'] > self.configured_duration,
hitting_limits=data['hitting_limits'],
throttled_time=data['throttled_time'],
io_throttled_time=data['io_throttled_time'],
wordpress=data['wordpress'],
)
)
# check buffer in same lock to prevent race conditions
# between threads modifying buffer
if len(self._buffer) >= self.BUFFER_SIZE:
objects_per_thread = self._buffer[:]
self._buffer = []
self.flush_buffer(objects_per_thread)
self.logger.debug('[%s] Released lock to handle request counters',
current_thread().name)
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