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1# Copyright 2015 The Chromium Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5"""
6This module is designed to report metadata in a separated thread to avoid the
7performance overhead of sending data to Elasticsearch using HTTP.
8
9"""
10
11import logging
12import Queue
13import time
14import threading
15
16import common
17from autotest_lib.client.common_lib.cros.graphite import autotest_es
18from autotest_lib.scheduler import email_manager
19# The metadata_reporter thread runs inside scheduler process, thus it doesn't
20# need to setup django, otherwise, following import is needed:
21# from autotest_lib.frontend import setup_django_environment
22from autotest_lib.site_utils import server_manager_utils
23
24
25# Number of seconds to wait before checking queue again for uploading data.
26_REPORT_INTERVAL_SECONDS = 5
27
28_MAX_METADATA_QUEUE_SIZE = 1000000
29_MAX_UPLOAD_SIZE = 50000
30# The number of seconds for upload to fail continuously. After that, upload will
31# be limited to 1 entry.
32_MAX_UPLOAD_FAIL_DURATION = 600
33# Number of entries to retry when the previous upload failed continueously for
34# the duration of _MAX_UPLOAD_FAIL_DURATION.
35_MIN_RETRY_ENTRIES = 10
36# Queue to buffer metadata to be reported.
37metadata_queue = Queue.Queue(_MAX_METADATA_QUEUE_SIZE)
38
39_report_lock = threading.Lock()
40_abort = threading.Event()
41_queue_full = threading.Event()
42
43def queue(data):
44    """Queue metadata to be uploaded in reporter thread.
45
46    If the queue is full, an error will be logged for the first time the queue
47    becomes full. The call does not wait or raise Queue.Full exception, so
48    there is no overhead on the performance of caller, e.g., scheduler.
49
50    @param data: A metadata entry, which should be a dictionary.
51    """
52    try:
53        metadata_queue.put_nowait(data)
54        if _queue_full.is_set():
55            logging.info('Metadata queue is available to receive new data '
56                         'again.')
57            _queue_full.clear()
58    except Queue.Full:
59        if not _queue_full.is_set():
60            _queue_full.set()
61            logging.error('Metadata queue is full, cannot report data. '
62                          'Consider increasing the value of '
63                          '_MAX_METADATA_QUEUE_SIZE. Its current value is set '
64                          'to %d.', _MAX_METADATA_QUEUE_SIZE)
65
66
67def _email_alert():
68    """
69    """
70    if not server_manager_utils.use_server_db():
71        logging.debug('Server database not emailed, email alert is skipped.')
72        return
73    try:
74        server_manager_utils.confirm_server_has_role(hostname='localhost',
75                                                     role='scheduler')
76    except server_manager_utils.ServerActionError:
77        # Only email alert if the server is a scheduler, not shard.
78        return
79    subject = ('Metadata upload has been failing for %d seconds' %
80               _MAX_UPLOAD_FAIL_DURATION)
81    email_manager.manager.enqueue_notify_email(subject, '')
82    email_manager.manager.send_queued_emails()
83
84
85def _run():
86    """Report metadata in the queue until being aborted.
87    """
88    # Time when the first time upload failed. None if the last upload succeeded.
89    first_failed_upload = None
90    # True if email alert was sent when upload has been failing continuously
91    # for _MAX_UPLOAD_FAIL_DURATION seconds.
92    email_alert = False
93    upload_size = _MIN_RETRY_ENTRIES
94    try:
95        while True:
96            start_time = time.time()
97            data_list = []
98            if (first_failed_upload and
99                time.time() - first_failed_upload > _MAX_UPLOAD_FAIL_DURATION):
100                upload_size = _MIN_RETRY_ENTRIES
101                if not email_alert:
102                    _email_alert()
103                    email_alert = True
104            else:
105                upload_size = min(upload_size*2, _MAX_UPLOAD_SIZE)
106            while (not metadata_queue.empty() and len(data_list) < upload_size):
107                data_list.append(metadata_queue.get_nowait())
108            if data_list:
109                if autotest_es.bulk_post(data_list=data_list):
110                    time_used = time.time() - start_time
111                    logging.info('%d entries of metadata uploaded in %s '
112                                 'seconds.', len(data_list), time_used)
113                    first_failed_upload = None
114                    email_alert = False
115                else:
116                    logging.warn('Failed to upload %d entries of metadata, '
117                                 'they will be retried later.', len(data_list))
118                    for data in data_list:
119                        queue(data)
120                    if not first_failed_upload:
121                        first_failed_upload = time.time()
122            sleep_time = _REPORT_INTERVAL_SECONDS - time.time() + start_time
123            if sleep_time < 0:
124                sleep_time = 0.5
125            _abort.wait(timeout=sleep_time)
126    except Exception as e:
127        logging.error('Metadata reporter thread failed with error: %s', e)
128        raise
129    finally:
130        logging.info('Metadata reporting thread is exiting.')
131        _abort.clear()
132        _report_lock.release()
133
134
135def start():
136    """Start the thread to report metadata.
137    """
138    # The lock makes sure there is only one reporting thread working.
139    if _report_lock.locked():
140        logging.error('There is already a metadata reporter thread.')
141        return
142
143    _report_lock.acquire()
144    reporting_thread = threading.Thread(target=_run)
145    # Make it a daemon thread so it doesn't need to be closed explicitly.
146    reporting_thread.setDaemon(True)
147    reporting_thread.start()
148    logging.info('Metadata reporting thread is started.')
149
150
151def abort():
152    """Abort the thread to report metadata.
153
154    The call will wait up to 5 seconds for existing data to be uploaded.
155    """
156    if  not _report_lock.locked():
157        logging.error('The metadata reporting thread has already exited.')
158        return
159
160    _abort.set()
161    logging.info('Waiting up to %s seconds for metadata reporting thread to '
162                 'complete.', _REPORT_INTERVAL_SECONDS)
163    _abort.wait(_REPORT_INTERVAL_SECONDS)
164