From 4a861749ee23a14974ca9222baa2f9b7d47c38d9 Mon Sep 17 00:00:00 2001
From: Bryan Newbold <bnewbold@robocracy.org>
Date: Sat, 6 Apr 2019 21:15:48 -0700
Subject: first draft harvesters using confluent-kafka

---
 python/fatcat_tools/harvest/harvest_common.py | 40 +++++++++++++++++++--------
 1 file changed, 29 insertions(+), 11 deletions(-)

(limited to 'python/fatcat_tools/harvest/harvest_common.py')

diff --git a/python/fatcat_tools/harvest/harvest_common.py b/python/fatcat_tools/harvest/harvest_common.py
index da06275f..90f499da 100644
--- a/python/fatcat_tools/harvest/harvest_common.py
+++ b/python/fatcat_tools/harvest/harvest_common.py
@@ -8,6 +8,8 @@ from requests.adapters import HTTPAdapter
 # unclear why pylint chokes on this import. Recent 'requests' and 'urllib3' are
 # in Pipenv.lock, and there are no errors in QA
 from requests.packages.urllib3.util.retry import Retry # pylint: disable=import-error
+from confluent_kafka import Producer, Consumer, TopicPartition, KafkaException, \
+    OFFSET_BEGINNING
 
 
 # Used for parsing ISO date format (YYYY-MM-DD)
@@ -104,14 +106,14 @@ class HarvestState:
             date = datetime.datetime.strptime(state['completed-date'], DATE_FMT).date()
             self.complete(date)
 
-    def complete(self, date, kafka_topic=None):
+    def complete(self, date, kafka_topic=None, kafka_config=None):
         """
         Records that a date has been processed successfully.
 
         Updates internal state and returns a JSON representation to be
         serialized. Will publish to a kafka topic if passed as an argument.
 
-        kafka_topic should have type pykafka.Topic (not str)
+        kafka_topic should be a string. A producer will be created and destroyed.
         """
         try:
             self.to_process.remove(date)
@@ -123,25 +125,41 @@ class HarvestState:
             'completed-date': str(date),
         }).encode('utf-8')
         if kafka_topic:
-            with kafka_topic.get_sync_producer() as producer:
-                producer.produce(state_json)
+            assert(kafka_config)
+            def fail_fast(err, msg):
+                if err:
+                    raise KafkaException(err)
+            print("Commiting status to Kafka: {}".format(kafka_topic))
+            producer = Producer(kafka_config)
+            producer.produce(kafka_topic, state_json, on_delivery=fail_fast)
+            producer.flush()
         return state_json
 
-    def initialize_from_kafka(self, kafka_topic):
+    def initialize_from_kafka(self, kafka_topic, kafka_config):
         """
-        kafka_topic should have type pykafka.Topic (not str)
+        kafka_topic should have type str
         """
         if not kafka_topic:
             return
 
-        print("Fetching state from kafka topic: {}".format(kafka_topic.name))
-        consumer = kafka_topic.get_simple_consumer(consumer_timeout_ms=1000)
+        print("Fetching state from kafka topic: {}".format(kafka_topic))
+        conf = kafka_config.copy()
+        conf.update({
+            'auto.offset.reset': 'earliest',
+            'session.timeout.ms': 10000,
+            'group.id': kafka_topic + "-init",
+        })
+        consumer = Consumer(conf)
+        consumer.assign([TopicPartition(kafka_topic, 0, OFFSET_BEGINNING)])
         c = 0
         while True:
-            msg = consumer.consume(block=True)
+            msg = consumer.poll(timeout=1.0)
             if not msg:
                 break
-            #sys.stdout.write('.')
-            self.update(msg.value.decode('utf-8'))
+            if msg.error():
+                raise KafkaException(msg.error())
+            sys.stdout.write('.') # XXX:
+            self.update(msg.value().decode('utf-8'))
             c += 1
+        consumer.close()
         print("... got {} state update messages, done".format(c))
-- 
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