Specifying replication factor in Confluent Kafka Python Client - apache-kafka

Question

I have setup a Single broker instance of Kafka along with Zookeeper, Kafka-tools,Schema-registry and control-center.The setup is done using docker compose and using the Confluent provided images.Here is how the docker-compose looks like:
zookeeper:
image: confluentinc/cp-zookeeper:latest
environment:
ZOOKEEPER_CLIENT_PORT: 2181
ZOOKEEPER_TICK_TIME: 2000
ports:
- 2181:2181
broker:
image: confluentinc/cp-server:latest
depends_on:
- zookeeper
ports:
- 9092:9092
environment:
KAFKA_BROKER_ID: 1
KAFKA_ZOOKEEPER_CONNECT: "zookeeper:2181"
KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: PLAINTEXT:PLAINTEXT,PLAINTEXT_HOST:PLAINTEXT
KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://broker:29092,PLAINTEXT_HOST://localhost:9092
KAFKA_METRIC_REPORTERS: io.confluent.metrics.reporter.ConfluentMetricsReporter
KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
KAFKA_GROUP_INITIAL_REBALANCE_DELAY_MS: 0
KAFKA_CONFLUENT_LICENSE_TOPIC_REPLICATION_FACTOR: 1
CONFLUENT_METRICS_REPORTER_BOOTSTRAP_SERVERS: broker:29092
CONFLUENT_METRICS_REPORTER_ZOOKEEPER_CONNECT: zookeeper:2181
CONFLUENT_METRICS_REPORTER_TOPIC_REPLICAS: 1
CONFLUENT_METRICS_ENABLE: "true"
CONFLUENT_SUPPORT_CUSTOMER_ID: "anonymous"
kafka-tools:
image: confluentinc/cp-kafka:latest
hostname: kafka-tools
container_name: kafka-tools
command: ["tail", "-f", "/dev/null"]
network_mode: "host"
schema-registry:
image: confluentinc/cp-schema-registry:5.5.0
hostname: schema-registry
container_name: schema-registry
depends_on:
- zookeeper
- broker
ports:
- "8081:8081"
environment:
SCHEMA_REGISTRY_HOST_NAME: schema-registry
SCHEMA_REGISTRY_KAFKASTORE_CONNECTION_URL: "zookeeper:2181"
control-center:
image: confluentinc/cp-enterprise-control-center:latest
hostname: control-center
container_name: control-center
depends_on:
- zookeeper
- broker
- schema-registry
ports:
- "9021:9021"
environment:
CONTROL_CENTER_BOOTSTRAP_SERVERS: 'broker:29092'
CONTROL_CENTER_ZOOKEEPER_CONNECT: 'zookeeper:2181'
CONTROL_CENTER_SCHEMA_REGISTRY_URL: "http://schema-registry:8081"
CONTROL_CENTER_REPLICATION_FACTOR: 1
CONTROL_CENTER_INTERNAL_TOPICS_PARTITIONS: 1
CONTROL_CENTER_MONITORING_INTERCEPTOR_TOPIC_PARTITIONS: 1
CONFLUENT_METRICS_TOPIC_REPLICATION: 1
PORT: 9021
Trying to the confluent-kafka python client to create the Producer and Consumer application.The following is the code of my Kafka producer:
from datetime import datetime
import os
import json
from uuid import uuid4
from confluent_kafka import SerializingProducer
from confluent_kafka.serialization import StringSerializer
from confluent_kafka.schema_registry import SchemaRegistryClient
from confluent_kafka.schema_registry.json_schema import JSONSerializer
class BotExecutionProducer(object):
"""
Class represents the
Bot execution Stats
"""
def __init__(self,ticketId,accountId,executionTime,status):
self.ticketId = ticketId
self.accountId = accountId
self.executionTime = executionTime
self.timestamp = str(datetime.now())
self.status = status
def botexecution_to_dict(self,botexecution,ctx):
"""
Returns a Dict representation of the
KafkaBotExecution instance
botexecution : KafkaBotExecution instance
ctx: SerializaionContext
"""
return dict(ticketId=self.ticketId,
accountId=self.accountId,
executionTime=self.executionTime,
timestamp=self.timestamp,
status=self.status
)
def delivery_report(self,err, msg):
"""
Reports the failure or success of a message delivery.
"""
if err is not None:
print("Delivery failed for User record {}: {}".format(msg.key(), err))
return
print('User record {} successfully produced to {} [{}] at offset {}'.format(
msg.key(), msg.topic(), msg.partition(), msg.offset()))
def send(self):
"""
Will connect to Kafka Broker
validate and send the message
"""
topic = "bots.execution"
schema_str = """
{
"$schema": "http://json-schema.org/draft-07/schema#",
"title": "BotExecutions",
"description": "BotExecution Stats",
"type": "object",
"properties": {
"ticketId": {
"description": "Ticket ID",
"type": "string"
},
"accountId": {
"description": "Customer's AccountID",
"type": "string"
},
"executionTime": {
"description": "Bot Execution time in seconds",
"type": "number"
},
"timestamp": {
"description": "Timestamp",
"type": "string"
},
"status": {
"description": "Execution Status",
"type": "string"
}
},
"required": [ "ticketId", "accountId", "executionTime", "timestamp", "status"]
}
"""
schema_registry_conf = {'url': 'http://localhost:8081'}
schema_registry_client = SchemaRegistryClient(schema_registry_conf)
json_serializer = JSONSerializer(schema_str,schema_registry_client,self.botexecution_to_dict)
producer_conf = {
'bootstrap.servers': "localhost:9092",
'key.serializer': StringSerializer('utf_8'),
'value.serializer': json_serializer,
'acks': 0,
}
producer = SerializingProducer(producer_conf)
print(f'Producing records to topic {topic}')
producer.poll(0.0)
try:
print(self)
producer.produce(topic=topic,key=str(uuid4()),partition=1,
value=self,on_delivery=self.delivery_report)
except ValueError:
print("Invalid Input,discarding record.....")
Now when I execute the code it should create a Kafka topic and push the JSON data to that topic, but that does not seem to work it keeps showing an error that a replication factor of 3 has been specified when there is only one broker.is there a way to define the replication factor in the above code.The kafka borker works perfectly when do the same using the Kafka cli.
Is there something that I am missing?

Answer 1

I'm not sure the full difference between cp-server and cp-kafka images, but you can add a variable for the default replication factor of automatically created topics
KAFKA_DEFAULT_REPLICATION_FACTOR: 1
If that doesn't work, import and use AdminClient