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-rw-r--r--python/fatcat_tools/changelog_workers.py122
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diff --git a/python/fatcat_tools/changelog_workers.py b/python/fatcat_tools/changelog_workers.py
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+
+import json
+import time
+from itertools import islice
+from fatcat.worker_common import FatcatWorker
+from pykafka.common import OffsetType
+
+
+class FatcatChangelogWorker(FatcatWorker):
+ """
+ Periodically polls the fatcat API looking for new changelogs. When they are
+ found, fetch them and push (as JSON) into a Kafka topic.
+ """
+
+ def __init__(self, api_host_url, kafka_hosts, produce_topic, poll_interval=10.0, offset=None):
+ # TODO: should be offset=0
+ super().__init__(kafka_hosts=kafka_hosts,
+ produce_topic=produce_topic,
+ api_host_url=api_host_url)
+ self.poll_interval = poll_interval
+ self.offset = offset # the fatcat changelog offset, not the kafka offset
+
+ def most_recent_message(self, topic):
+ """
+ Tries to fetch the most recent message from a given topic.
+ This only makes sense for single partition topics, though could be
+ extended with "last N" behavior.
+
+ Following "Consuming the last N messages from a topic"
+ from https://pykafka.readthedocs.io/en/latest/usage.html#consumer-patterns
+ """
+ consumer = topic.get_simple_consumer(
+ auto_offset_reset=OffsetType.LATEST,
+ reset_offset_on_start=True)
+ offsets = [(p, op.last_offset_consumed - 1)
+ for p, op in consumer._partitions.items()]
+ offsets = [(p, (o if o > -1 else -2)) for p, o in offsets]
+ if -2 in [o for p, o in offsets]:
+ return None
+ else:
+ consumer.reset_offsets(offsets)
+ msg = islice(consumer, 1)
+ if msg:
+ return list(msg)[0].value
+ else:
+ return None
+
+ def run(self):
+ topic = self.kafka.topics[self.produce_topic]
+ # On start, try to consume the most recent from the topic, and using
+ # that as the starting offset. Note that this is a single-partition
+ # topic
+ if self.offset is None:
+ print("Checking for most recent changelog offset...")
+ msg = self.most_recent_message(topic)
+ if msg:
+ self.offset = json.loads(msg.decode('utf-8'))['index']
+ else:
+ self.offset = 1
+
+ with topic.get_sync_producer() as producer:
+ while True:
+ latest = int(self.api.get_changelog(limit=1)[0].index)
+ if latest > self.offset:
+ print("Fetching changelogs from {} through {}".format(
+ self.offset+1, latest))
+ for i in range(self.offset+1, latest+1):
+ cle = self.api.get_changelog_entry(i)
+ obj = self.api.api_client.sanitize_for_serialization(cle)
+ producer.produce(
+ message=json.dumps(obj).encode('utf-8'),
+ partition_key=None,
+ timestamp=None,
+ #XXX: timestamp=cle.timestamp,
+ )
+ self.offset = i
+ print("Sleeping {} seconds...".format(self.poll_interval))
+ time.sleep(self.poll_interval)
+
+
+class FatcatEntityUpdatesWorker(FatcatWorker):
+ """
+ Consumes from the changelog topic and publishes expanded entities (fetched
+ from API) to update topics.
+
+ For now, only release updates are published.
+ """
+
+ def __init__(self, api_host_url, kafka_hosts, consume_topic, release_topic):
+ super().__init__(kafka_hosts=kafka_hosts,
+ consume_topic=consume_topic,
+ api_host_url=api_host_url)
+ self.release_topic = release_topic
+ self.consumer_group = "entity-updates"
+
+ def run(self):
+ changelog_topic = self.kafka.topics[self.consume_topic]
+ release_topic = self.kafka.topics[self.release_topic]
+
+ consumer = changelog_topic.get_balanced_consumer(
+ consumer_group=self.consumer_group,
+ managed=True,
+ auto_offset_reset=OffsetType.LATEST,
+ reset_offset_on_start=False,
+ )
+
+ with release_topic.get_sync_producer() as producer:
+ for msg in consumer:
+ cle = json.loads(msg.value.decode('utf-8'))
+ #print(cle)
+ release_edits = cle['editgroup']['edits']['releases']
+ for re in release_edits:
+ ident = re['ident']
+ release = self.api.get_release(ident, expand="files,container")
+ release_dict = self.api.api_client.sanitize_for_serialization(release)
+ producer.produce(
+ message=json.dumps(release_dict).encode('utf-8'),
+ partition_key=ident.encode('utf-8'),
+ timestamp=None,
+ )
+ consumer.commit_offsets()
+