Python producer (confluent-kafka) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a Kafka producer using confluent-kafka.

Kafka

from confluent_kafka import Producer

conf = {'bootstrap.servers': [1]
producer = Producer(conf)

Drag options to blanks, or click blank then click option'

A'kafka:2181'

B'localhost:9092'

C'127.0.0.1:2181'

D'localhost:2181'

Attempts:

3 left

💡 Hint

Common Mistakes

Using Zookeeper port 2181 instead of Kafka broker port 9092.

Using incorrect IP or hostname format.

The bootstrap.servers config requires the Kafka broker address with port 9092, not the Zookeeper port 2181.

2fill in blank

medium

Complete the code to send a message to the topic 'test-topic'.

Kafka

producer.produce([1], key='key1', value='Hello Kafka!')
producer.flush()

Drag options to blanks, or click blank then click option'

A'topic1'

B'my-topic'

C'kafka-topic'

D'test-topic'

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong topic name.

Forgetting to call flush() to ensure delivery.

The message must be sent to the topic named test-topic as specified.

3fill in blank

hard

Fix the error in the delivery report callback function to print success or failure.

Kafka

def delivery_report(err, msg):
    if [1] is not None:
        print(f"Message delivery failed: {err}")
    else:
        print(f"Message delivered to {msg.topic()} [{msg.partition()}]")

Drag options to blanks, or click blank then click option'

Aerr

Bmsg

Cerror

DNone

Attempts:

3 left

💡 Hint

Common Mistakes

Checking the wrong variable for error.

Using 'error' instead of 'err'.

The callback receives err which is None on success, so checking if err is not None detects failure.

4fill in blank

hard

Fill both blanks to produce messages with keys and values from a list.

Kafka

messages = [('key1', 'value1'), ('key2', 'value2')]
for [1], [2] in messages:
    producer.produce('my-topic', key=[1], value=[2])
producer.flush()

Drag options to blanks, or click blank then click option'

Akey

Bk

Cvalue

Dv

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names not matching the unpacked tuple.

Using the same variable name for both key and value.

In the loop, k and v are used as variable names for key and value respectively.

5fill in blank

hard

Fill all three blanks to create a producer with a delivery callback and send a message.

Kafka

def delivery_report([1], [2]):
    if [1] is not None:
        print(f"Failed: {err}")
    else:
        print(f"Delivered to {msg.topic()}")

conf = {'bootstrap.servers': 'localhost:9092'}
producer = Producer(conf)
producer.produce('topic1', key='k1', value='v1', callback=[3])
producer.flush()

Drag options to blanks, or click blank then click option'

Aerr

Bmsg

Cdelivery_report

Dcallback

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong parameter names in the callback.

Passing a string instead of the function as callback.

The delivery callback function takes err and msg as parameters, and the callback argument is the function delivery_report.

Practice

1. What is the main purpose of the produce() method in the Python confluent-kafka producer?

easy

A. To consume messages from a Kafka topic

B. To connect to the Kafka server

C. To send a message to a Kafka topic

D. To wait for all messages to be delivered

Solution

1. Step 1: Understand the role of produce()

   The produce() method is used to send messages to a Kafka topic from the producer.

2. Step 2: Differentiate from other methods

   flush() waits for messages to be sent, and connection is set by configuration, not produce().

3. Final Answer:

   To send a message to a Kafka topic -> Option C

4. Quick Check:

   produce() sends messages [OK]

Hint: Remember: produce() means send message [OK]

Common Mistakes:

• Confusing produce() with flush()
• Thinking produce() connects to Kafka
• Mixing producer and consumer roles

2. Which of the following is the correct way to set the Kafka server address in the Python confluent-kafka producer configuration?

easy

A. "bootstrap.servers" : "localhost:9092"

B. "server.bootstrap" : "localhost:9092"

C. "kafka.server" : "localhost:9092"

D. "broker.address" : "localhost:9092"

Solution

1. Step 1: Recall the correct configuration key

   The correct key to specify Kafka server address is bootstrap.servers.

2. Step 2: Match the option

   Only "bootstrap.servers" : "localhost:9092" uses the exact key "bootstrap.servers" with a valid address format.

3. Final Answer:

   "bootstrap.servers" : "localhost:9092" -> Option A

4. Quick Check:

   Kafka server config = bootstrap.servers [OK]

Hint: Look for exact key: bootstrap.servers [OK]

Common Mistakes:

• Swapping key names like server.bootstrap
• Using incorrect keys like kafka.server
• Missing quotes or wrong format

3. What will be the output of the following Python code using confluent-kafka producer?

from confluent_kafka import Producer

p = Producer({'bootstrap.servers': 'localhost:9092'})
p.produce('my_topic', key='key1', value='hello')
p.flush()
print('Message sent')

medium

A. Error: No Kafka server found

B. hello

C. No output

D. Message sent

Solution

1. Step 1: Understand the code flow

   The code creates a producer, sends a message to 'my_topic', waits for delivery with flush(), then prints 'Message sent'.

2. Step 2: Identify the printed output

   The only print statement outputs the string 'Message sent'. The message sending is asynchronous but flush ensures completion before print.

3. Final Answer:

   Message sent -> Option D

4. Quick Check:

   flush() waits, then print runs [OK]

Hint: flush() waits, print runs after sending [OK]

Common Mistakes:

• Expecting message value to print
• Ignoring flush() effect
• Assuming error without Kafka running

4. Identify the error in this Python confluent-kafka producer code:

from confluent_kafka import Producer

p = Producer({'bootstrap.servers': 'localhost:9092'})
p.produce('my_topic', key='key1', 'hello')
p.flush()

medium

A. Missing key argument in produce()

B. Incorrect order of arguments in produce()

C. flush() called before produce()

D. Missing import statement

Solution

1. Step 1: Check produce() argument order

   The produce() method expects positional arguments first (topic, optionally value), followed only by keyword arguments. Here, key='key1' (keyword) is followed by 'hello' (positional), causing SyntaxError: positional argument follows keyword argument.

2. Step 2: Identify correct usage

   Correct usage: produce('my_topic', value='hello') or produce('my_topic', key='key1', value='hello').

3. Final Answer:

   Incorrect order of arguments in produce() -> Option B

4. Quick Check:

   Positional args before keywords [OK]

Hint: Positional args must precede keywords [OK]

Common Mistakes:

• Placing positional argument after keyword argument
• Mixing positional and keyword argument order
• Forgetting Python positional-before-keyword rule

5. You want to send multiple messages to Kafka and ensure all are delivered before your program exits. Which sequence of calls is correct using confluent-kafka producer in Python?

hard

A. Call produce() for each message, then call flush() once at the end

B. Call flush() after each produce() call

C. Call flush() before any produce() calls

D. Call produce() once, then call flush() multiple times

Solution

1. Step 1: Understand message sending behavior

   produce() queues messages asynchronously. Calling it multiple times queues multiple messages.

2. Step 2: Use flush() to wait for delivery

   Calling flush() once after all produce() calls waits for all messages to be sent before program exit.

3. Final Answer:

   Call produce() for each message, then call flush() once at the end -> Option A

4. Quick Check:

   Produce many, flush once after all [OK]

Hint: Flush once after all produce calls to wait [OK]

Common Mistakes:

• Flushing after every produce (slow)
• Flushing before producing messages
• Not flushing at all causing lost messages