Source connectors in Kafka - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Kafka Connect source connector configuration?

Given this JSON configuration for a Kafka Connect source connector, what will be the value of the tasks.max property when the connector starts?

Kafka

{
  "name": "my-source-connector",
  "config": {
    "connector.class": "FileStreamSource",
    "tasks.max": "3",
    "file": "/tmp/input.txt",
    "topic": "test-topic"
  }
}

A Error: tasks.max must be an integer

B 1

C 0

D 3

💡 Hint

Check the value assigned to tasks.max in the config JSON.

The tasks.max property is set to the string "3" which Kafka Connect parses as integer 3, so the connector will start with 3 tasks.

🧠 Conceptual

intermediate

Which Kafka Connect source connector property controls the maximum number of tasks?

In Kafka Connect source connectors, which configuration property defines the maximum number of tasks that can be created to read data?

A offset.flush.interval.ms

B max.poll.records

C tasks.max

D batch.size

💡 Hint

It controls parallelism of the connector.

The tasks.max property controls how many tasks the connector can create to read data in parallel.

❓ Predict Output

advanced

What error does this source connector configuration cause?

What error will Kafka Connect raise when starting this source connector?

Kafka

{
  "name": "invalid-connector",
  "config": {
    "connector.class": "FileStreamSource",
    "tasks.max": "zero",
    "file": "/tmp/input.txt",
    "topic": "test-topic"
  }
}

A No error, tasks.max defaults to 1

B Error: tasks.max must be a positive integer

C Error: file path not found

D Error: topic name missing

💡 Hint

Check the value type of tasks.max.

The tasks.max property must be a positive integer. The string "zero" is invalid and causes a configuration error.

🚀 Application

advanced

How many tasks will be created with this source connector config?

If a source connector is configured with tasks.max set to 5, but the connector's taskConfigs method returns only 3 task configurations, how many tasks will Kafka Connect create?

A 3

B 5

C 0

D Error: mismatch between tasks.max and taskConfigs

💡 Hint

The number of tasks is limited by the number of task configurations returned.

Kafka Connect creates as many tasks as the number of task configurations returned by the connector, up to tasks.max. Here, only 3 task configs are returned, so 3 tasks are created.

🔧 Debug

expert

Why does this source connector fail to start?

This source connector configuration fails to start. What is the cause?

Kafka

{
  "name": "my-source",
  "config": {
    "connector.class": "org.apache.kafka.connect.file.FileStreamSourceConnector",
    "tasks.max": "2",
    "file": "/tmp/input.txt"
  }
}

A Missing required property: topic

B Invalid connector.class value

C tasks.max must be an integer, not string

D File path does not exist

💡 Hint

Check if all required properties for FileStreamSourceConnector are present.

The FileStreamSourceConnector requires the 'topic' property to specify the Kafka topic to write to. Without it, the connector fails to start.