Transform and converter chains in Kafka - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a simple transformation to the Kafka Connect chain.

Kafka

transforms=AddPrefix
transforms.AddPrefix.type=[1]

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

Aorg.apache.kafka.connect.transforms.InsertField$Value

Borg.apache.kafka.connect.transforms.SetSchemaMetadata

Corg.apache.kafka.connect.transforms.RegexRouter

Dorg.apache.kafka.connect.transforms.ValueToKey

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a transform that modifies message keys or values instead of topic names.

The RegexRouter transform is used to modify topic names in the chain.

2fill in blank

medium

Complete the code to configure a converter chain for JSON data.

Kafka

key.converter=org.apache.kafka.connect.json.JsonConverter
value.converter=[1]

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

Aorg.apache.kafka.connect.converters.ByteArrayConverter

Borg.apache.kafka.connect.storage.StringConverter

Corg.apache.kafka.connect.avro.AvroConverter

Dorg.apache.kafka.connect.json.JsonConverter

Attempts:

3 left

💡 Hint

Common Mistakes

Using different converters for key and value causing data format mismatch.

Both key and value converters should be set to JsonConverter for JSON data.

3fill in blank

hard

Fix the error in the transform chain configuration to correctly apply a value transformation.

Kafka

transforms=MaskField
transforms.MaskField.type=[1]

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

Aorg.apache.kafka.connect.transforms.ReplaceField$Value

Borg.apache.kafka.connect.transforms.MaskField$Value

Corg.apache.kafka.connect.transforms.MaskField$Key

Dorg.apache.kafka.connect.transforms.InsertField$Value

Attempts:

3 left

💡 Hint

Common Mistakes

Using MaskField$Key when the transformation should apply to the message value.

The MaskField$Value transform masks fields in the message value, which is the intended behavior here.

4fill in blank

hard

Fill both blanks to configure a converter chain with Avro and a transform to route topics.

Kafka

key.converter=[1]
value.converter=[2]

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

Aorg.apache.kafka.connect.json.JsonConverter

Borg.apache.kafka.connect.storage.StringConverter

Cio.confluent.connect.avro.AvroConverter

Dorg.apache.kafka.connect.converters.ByteArrayConverter

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing different converters for key and value causing serialization errors.

Both key and value converters should be set to AvroConverter for Avro data format.

5fill in blank

hard

Fill all three blanks to create a transform chain that renames topics and masks a field in the value.

Kafka

transforms=RouteTopic,MaskValue
transforms.RouteTopic.type=[1]
transforms.MaskValue.type=[2]
transforms.MaskValue.fields=[3]

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

Aorg.apache.kafka.connect.transforms.RegexRouter

Borg.apache.kafka.connect.transforms.MaskField$Value

Cpassword

Dorg.apache.kafka.connect.transforms.InsertField$Value

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing MaskField$Key with MaskField$Value.

Not specifying the field name to mask.

The RegexRouter transform renames topics, MaskField$Value masks fields in the value, and password is the field to mask.

Practice

1. What is the main purpose of using transform and converter chains in Kafka Connect?

easy

A. To monitor Kafka cluster health

B. To store data permanently in Kafka topics

C. To create new Kafka topics automatically

D. To change data step-by-step during processing

Solution

1. Step 1: Understand transform and converter chains

   Transform and converter chains let you modify data in stages as it moves through Kafka Connect.

2. Step 2: Identify the main purpose

   The main goal is to change or clean data step-by-step automatically before it reaches its destination.

3. Final Answer:

   To change data step-by-step during processing -> Option D

4. Quick Check:

   Transform chains = step-by-step data change [OK]

Hint: Transforms modify data stepwise in Kafka Connect [OK]

Common Mistakes:

• Confusing transform chains with topic creation
• Thinking transforms monitor cluster health
• Assuming transforms store data permanently

2. Which of the following is the correct way to list multiple transforms in Kafka Connect configuration?

easy

A. transforms=InsertField,ReplaceField

B. transforms=[InsertField, ReplaceField]

C. transforms: InsertField; ReplaceField

D. transforms = InsertField ReplaceField

Solution

1. Step 1: Recall Kafka Connect transform list syntax

   Transforms are listed as a comma-separated string without brackets or semicolons.

2. Step 2: Match the correct syntax

   transforms=InsertField,ReplaceField uses commas correctly: transforms=InsertField,ReplaceField.

3. Final Answer:

   transforms=InsertField,ReplaceField -> Option A

4. Quick Check:

   Comma-separated list = correct syntax [OK]

Hint: Use commas to separate transforms in config [OK]

Common Mistakes:

• Using brackets or semicolons instead of commas
• Adding spaces around commas incorrectly
• Using colons or spaces without commas

3. Given this Kafka Connect transform chain configuration:
transforms=InsertField,ReplaceField
transforms.InsertField.type=org.apache.kafka.connect.transforms.InsertField$Value
transforms.InsertField.static.field=source
transforms.InsertField.static.value=app1
transforms.ReplaceField.type=org.apache.kafka.connect.transforms.ReplaceField$Value
transforms.ReplaceField.renames=oldName:newName
What will happen to a record with value {"oldName":"data"}?

medium

A. The record value becomes {"newName":"data"} only

B. The record value becomes {"oldName":"data", "source":"app1"}

C. The record value becomes {"source":"app1", "newName":"data"}

D. The record value remains unchanged

Solution

1. Step 1: Apply InsertField transform

   This adds a field "source" with value "app1" to the record, so value becomes {"oldName":"data", "source":"app1"}.

2. Step 2: Apply ReplaceField transform

   This renames "oldName" to "newName", so final value is {"source":"app1", "newName":"data"}.

3. Final Answer:

   {"source":"app1", "newName":"data"} -> Option C

4. Quick Check:

   InsertField adds, ReplaceField renames = final value [OK]

Hint: Apply transforms in order listed [OK]

Common Mistakes:

• Applying transforms in wrong order
• Forgetting InsertField adds a new field
• Assuming ReplaceField deletes old field without rename

4. You configured a transform chain but get an error: "Unknown transform type". Which of these fixes the problem?

medium

A. Remove all transforms from the config

B. Correct the transform type class name in the config

C. Restart Kafka Connect without changing config

D. Increase Kafka Connect heap size

Solution

1. Step 1: Understand the error cause

   "Unknown transform type" means Kafka Connect cannot find the class name specified for the transform.

2. Step 2: Fix the transform type

   Correcting the transform type class name in the configuration ensures Kafka Connect can load it properly.

3. Final Answer:

   Correct the transform type class name in the config -> Option B

4. Quick Check:

   Fix class name to resolve unknown transform error [OK]

Hint: Check transform class names carefully [OK]

Common Mistakes:

• Ignoring typo in transform type
• Restarting without fixing config
• Assuming memory issues cause this error

5. You want to create a transform chain that first removes sensitive fields, then adds a timestamp, and finally converts the record to JSON string. Which order of transforms is correct?

hard

A. RemoveFields, InsertField (timestamp), StringConverter

B. StringConverter, RemoveFields, InsertField (timestamp)

C. InsertField (timestamp), RemoveFields, StringConverter

D. RemoveFields, StringConverter, InsertField (timestamp)

Solution

1. Step 1: Remove sensitive fields first

   Removing fields must happen before adding new data or converting formats to avoid leaking sensitive info.

2. Step 2: Add timestamp after cleaning

   InsertField adds the timestamp field next, so the record has the new info before conversion.

3. Step 3: Convert record to JSON string last

   StringConverter should be last to convert the final cleaned and enriched record into a JSON string.

4. Final Answer:

   RemoveFields, InsertField (timestamp), StringConverter -> Option A

5. Quick Check:

   Clean, enrich, then convert = correct order [OK]

Hint: Clean data first, then add fields, convert last [OK]

Common Mistakes:

• Converting to string before removing fields
• Adding fields after conversion
• Wrong transform order causing data errors