Feature/kafka transactions

blockchainetl/jobs/exporters/kafka_exporter.py

@@ -2,7 +2,7 @@
 import json
 import logging
 
-from kafka import KafkaProducer
+from confluent_kafka import Producer
 
 from blockchainetl.jobs.exporters.converters.composite_item_converter import CompositeItemConverter
 
@@ -13,28 +13,41 @@ def __init__(self, output, item_type_to_topic_mapping, converters=()):
         self.item_type_to_topic_mapping = item_type_to_topic_mapping
         self.converter = CompositeItemConverter(converters)
         self.connection_url = self.get_connection_url(output)
-        print(self.connection_url)
-        self.producer = KafkaProducer(bootstrap_servers=self.connection_url)
+        self.topic_prefix = self.get_topic_prefix(output)
+        print(self.connection_url, self.topic_prefix)
+        self.producer = Producer({
+            'bootstrap.servers': self.connection_url,
+            'transactional.id': 'ethereumetl',
+            'enable.idempotence': True,
+        })
 
     def get_connection_url(self, output):
         try:
             return output.split('/')[1]
-        except KeyError:
-            raise Exception('Invalid kafka output param, It should be in format of "kafka/127.0.0.1:9092"')
+        except IndexError:
+            raise Exception('Invalid kafka output param, It should be in format of "kafka/127.0.0.1:9092" or "kafka/127.0.0.1:9092/<topic-prefix>"')
+
+    def get_topic_prefix(self, output):
+        try:
+            return output.split('/')[2] + "."
+        except IndexError:
+            return ''
 
     def open(self):
-        pass
+        self.producer.init_transactions()
 
     def export_items(self, items):
+        self.producer.begin_transaction()
         for item in items:
             self.export_item(item)
-
+        self.producer.commit_transaction()
+
     def export_item(self, item):
         item_type = item.get('type')
         if item_type is not None and item_type in self.item_type_to_topic_mapping:
             data = json.dumps(item).encode('utf-8')
-            print(data)
-            return self.producer.send(self.item_type_to_topic_mapping[item_type], value=data)
+            logging.debug(data)
+            return self.producer.produce(self.topic_prefix + self.item_type_to_topic_mapping[item_type], data)
         else:
             logging.warning('Topic for item type "{}" is not configured.'.format(item_type))
 
@@ -43,9 +56,8 @@ def convert_items(self, items):
             yield self.converter.convert_item(item)
 
     def close(self):
-        pass
-
-
+       pass
+
 def group_by_item_type(items):
     result = collections.defaultdict(list)
     for item in items:

docs/commands.md

@@ -213,7 +213,7 @@ e.g. `-e block,transaction,log,token_transfer,trace,contract,token`.
     - For Postgres: `--output=postgresql+pg8000://<user>:<password>@<host>:<port>/<database_name>`, 
     e.g. `--output=postgresql+pg8000://postgres:admin@127.0.0.1:5432/ethereum`.
     - For GCS:  `--output=gs://<bucket_name>`. Make sure to install and initialize `gcloud` cli.
-    - For Kafka:  `--output=kafka/<host>:<port>`, e.g. `--output=kafka/127.0.0.1:9092`
+    - For Kafka:  `--output=kafka/<host>:<port>/<optional: topic_prefix>`, e.g. `--output=kafka/127.0.0.1:9092` or `--output=kafka/127.0.0.1:9092/crypto_ethereum`.
     - Those output types can be combined with a comma e.g. `--output=gs://<bucket_name>,projects/<your-project>/topics/crypto_ethereum`
 
     The [schema](https://github.com/blockchain-etl/ethereum-etl-postgres/tree/master/schema) 

setup.py

@@ -46,7 +46,7 @@ def read(fname):
             'timeout-decorator==0.4.1',
             'google-cloud-pubsub==2.1.0',
             'google-cloud-storage==1.33.0',
-            'kafka-python==2.0.2',
+            'confluent-kafka==1.9.0',
             'sqlalchemy==1.4',
             'pg8000==1.16.6',
             # This library is a dependency for google-cloud-pubsub, starting from 0.3.22 it requires Rust,