From 519b90d7f539b667e919c220a53626e7a4ac48bf Mon Sep 17 00:00:00 2001
From: Martin Czygan <martin.czygan@gmail.com>
Date: Fri, 14 Feb 2020 14:32:57 +0100
Subject: pubmed ftp harvest and KafkaBs4XmlPusher

* add PubmedFTPWorker
* utils are currently stored alongside pubmed (e.g. ftpretr, xmlstream)
but may live elsewhere, as they are more generic
* add KafkaBs4XmlPusher
---
 python/fatcat_tools/importers/common.py | 65 +++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

(limited to 'python/fatcat_tools/importers/common.py')

diff --git a/python/fatcat_tools/importers/common.py b/python/fatcat_tools/importers/common.py
index 1ffbd6e7..1cb5529e 100644
--- a/python/fatcat_tools/importers/common.py
+++ b/python/fatcat_tools/importers/common.py
@@ -721,6 +721,71 @@ class Bs4XmlFileListPusher(RecordPusher):
         print(counts)
         return counts
 
+class KafkaBs4XmlPusher(RecordPusher):
+    """
+    Fetch XML for an article from Kafka, parse via Bs4.
+    """
+    def __init__(self, importer, kafka_hosts, kafka_env, topic_suffix, group, **kwargs):
+        self.importer = importer
+        self.consumer = make_kafka_consumer(
+            kafka_hosts,
+            kafka_env,
+            topic_suffix,
+            group,
+            kafka_namespace=kwargs.get('kafka_namespace', 'fatcat')
+        )
+        self.poll_interval = kwargs.get('poll_interval', 5.0)
+        self.consume_batch_size = kwargs.get('consume_batch_size', 100)
+
+    def run(self):
+        count = 0
+        last_push = datetime.datetime.now()
+        while True:
+            # Note: this is batch-oriented, because underlying importer is
+            # often batch-oriented, but this doesn't confirm that entire batch
+            # has been pushed to fatcat before commiting offset. Eg, consider
+            # case where there there is one update and thousands of creates;
+            # update would be lingering in importer, and if importer crashed
+            # never created.
+            # This is partially mitigated for the worker case by flushing any
+            # outstanding editgroups every 5 minutes, but there is still that
+            # window when editgroups might be hanging (unsubmitted).
+            batch = self.consumer.consume(
+                num_messages=self.consume_batch_size,
+                timeout=self.poll_interval)
+            print("... got {} kafka messages ({}sec poll interval)".format(
+                len(batch), self.poll_interval))
+            if not batch:
+                if datetime.datetime.now() - last_push > datetime.timedelta(minutes=5):
+                    # it has been some time, so flush any current editgroup
+                    self.importer.finish()
+                    last_push = datetime.datetime.now()
+                    #print("Flushed any partial import batch: {}".format(self.importer.counts))
+                continue
+            # first check errors on entire batch...
+            for msg in batch:
+                if msg.error():
+                    raise KafkaException(msg.error())
+            # ... then process
+            for msg in batch:
+                soup = BeautifulSoup(msg.value().decode('utf-8'), "xml")
+                self.importer.push_record(soup)
+                soup.decompose()
+                count += 1
+                if count % 500 == 0:
+                    print("Import counts: {}".format(self.importer.counts))
+            last_push = datetime.datetime.now()
+            for msg in batch:
+                # locally store offsets of processed messages; will be
+                # auto-commited by librdkafka from this "stored" value
+                self.consumer.store_offsets(message=msg)
+
+        # TODO: should catch UNIX signals (HUP?) to shutdown cleanly, and/or
+        # commit the current batch if it has been lingering
+        counts = self.importer.finish()
+        print(counts)
+        self.consumer.close()
+        return counts
 
 class KafkaJsonPusher(RecordPusher):
 
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