Revision 6ecf3d61db1d34d1432b66ac2ec5e325e3c186c1 authored by Stefano Zacchiroli on 21 October 2017, 14:47:03 UTC, committed by Stefano Zacchiroli on 21 October 2017, 14:47:03 UTC
1 parent 8915caf
listener.py
# Copyright (C) 2016-2017 The Software Heritage developers
# See the AUTHORS file at the top-level directory of this distribution
# License: GNU General Public License version 3, or any later version
# See top-level LICENSE file for more information
import json
import logging
import kafka
import msgpack
import swh.storage.db
from swh.core.config import load_named_config
CONFIG_BASENAME = 'storage/listener'
DEFAULT_CONFIG = {
'database': ('str', 'service=softwareheritage'),
'brokers': ('list[str]', ['getty.internal.softwareheritage.org']),
'topic_prefix': ('str', 'swh.tmp_journal.new'),
'poll_timeout': ('int', 10),
}
def decode_sha(value):
"""Decode the textual representation of a SHA hash"""
if isinstance(value, str):
return bytes.fromhex(value)
return value
def decode_json(value):
"""Decode a JSON value containing hashes and other types"""
value = json.loads(value)
return {k: decode_sha(v) for k, v in value.items()}
OBJECT_TYPES = {
'content',
'skipped_content',
'directory',
'revision',
'release',
'origin_visit',
'origin',
}
def register_all_notifies(db):
"""Register to notifications for all object types listed in OBJECT_TYPES"""
with db.transaction() as cur:
for object_type in OBJECT_TYPES:
db.register_listener('new_%s' % object_type, cur)
def dispatch_notify(topic_prefix, producer, notify):
"""Dispatch a notification to the proper topic"""
channel = notify.channel
if not channel.startswith('new_') or channel[4:] not in OBJECT_TYPES:
logging.warn("Got unexpected notify %s" % notify)
return
object_type = channel[4:]
topic = '%s.%s' % (topic_prefix, object_type)
data = decode_json(notify.payload)
producer.send(topic, value=data)
def run_from_config(config):
"""Run the Software Heritage listener from configuration"""
db = swh.storage.db.Db.connect(config['database'])
def key_to_kafka(key):
"""Serialize a key, possibly a dict, in a predictable way.
Duplicated from swh.journal to avoid a cyclic dependency."""
p = msgpack.Packer(use_bin_type=True)
if isinstance(key, dict):
return p.pack_map_pairs(sorted(key.items()))
else:
return p.pack(key)
producer = kafka.KafkaProducer(
bootstrap_servers=config['brokers'],
value_serializer=key_to_kafka,
)
register_all_notifies(db)
topic_prefix = config['topic_prefix']
poll_timeout = config['poll_timeout']
try:
while True:
for notify in db.listen_notifies(poll_timeout):
dispatch_notify(topic_prefix, producer, notify)
producer.flush()
except Exception:
logging.exception("Caught exception")
producer.flush()
if __name__ == '__main__':
logging.basicConfig(
level=logging.INFO,
format='%(asctime)s %(process)d %(levelname)s %(message)s'
)
config = load_named_config(CONFIG_BASENAME, DEFAULT_CONFIG)
run_from_config(config)
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