Victoria Bialas created KAFKA-12159:
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Summary: kafka-console-producer prompt should redisplay after an
error output
Key: KAFKA-12159
URL: https://issues.apache.org/jira/browse/KAFKA-12159
Project: Kafka
Issue Type: Bug
Components: producer , tools
Environment: Mac OSX Catalina 10.15.7, iTerm, Linux
Reporter: Victoria Bialas
*BLUF:* The kafka-console-producer should return its prompt after outputting an
error message (if it is still running, which in most cases, it is). Current
behaviour is it doesn't return a prompt, and hitting return at that point shuts
it down.
*DETAIL AND EXAMPLE:* The console producer utility behaves in a less than
optimal way when you get an error. It doesn’t return the producer prompt even
though the producer is still running and accessible. If you hit return after
the error, it shuts down the producer, forcing you to restart it when in fact
that wasn’t necessary.
This makes it confusing to demo to users in Docs how to test producers and
consumers in scenarios where an error is generated. (I am adding a tip o write
around this which will be published soon. It will be at the end of step 7 in
[Demo: Enabling Schema Validation on a Topic at the Command
Line|http://example.com].
Here is an example from Confluent Platform. The scenario has you try to send a
message with schema validation on (which will fail due to the message format),
then disable schema validation and resend the message or another in a similar
format, which should then succeed.
# With Confluent "schema validation" on, try to send a message that doesn't
conform to the schema defined for a topic.
*Producer*
{code:java}
Last login: Wed Jan 6 17:51:01 on ttys004
Vickys-MacBook-Pro:~ vicky$ kafka-console-producer --broker-list localhost:9092
--topic test-schemas --property parse.key=true --property key.separator=,
>1,my first record
>2,my second record
>[2021-01-06 18:25:08,722] ERROR Error when sending message to topic
>test-schemas with key: 1 bytes, value: 16 bytes with error:
>(org.apache.kafka.clients.producer.internals.ErrorLoggingCallback)
org.apache.kafka.common.InvalidRecordException: This record has failed the
validation on broker and hence will be rejected.
org.apache.kafka.common.KafkaException: No key found on line 3:
at
kafka.tools.ConsoleProducer$LineMessageReader.readMessage(ConsoleProducer.scala:290)
at kafka.tools.ConsoleProducer$.main(ConsoleProducer.scala:51)
at kafka.tools.ConsoleProducer.main(ConsoleProducer.scala)
Vickys-MacBook-Pro:~ vicky$ kafka-console-producer --broker-list localhost:9092
--topic test-schemas --property parse.key=true --property key.separator=,
>3,my third record
>
{code}
You can see that you lose the producer prompt after the error and get only a
blank line, which leads you to believe you've lost the producer (it's actually
still running). If you hit return, the producer shuts down, forcing you to
restart the producer to continue (when in fact, this isn't necessary.)
*Consumer*
The consumer still shows only a previous message that was sent when schema
validation was disabled earlier in the demo.
{code:java}
Vickys-MacBook-Pro:~ vicky$ kafka-console-consumer --bootstrap-server
localhost:9092 --from-beginning --topic test-schemas --property
print.key=trueVickys-MacBook-Pro:~ vicky$ kafka-console-consumer
--bootstrap-server localhost:9092 --from-beginning --topic test-schemas
--property print.key=true1
my first record
{code}
# If instead, after disabling schema validation in a different shell, you
return to the producer window and copy-paste or type the message on the blank
line following the error, and then hit return, the message will send, and you
will see it in the running consumer.
*Producer*
{code:java}
Vickys-MacBook-Pro:~ vicky$ kafka-console-producer --broker-list localhost:9092
--topic test-schemas --property parse.key=true --property key.separator=,
>1,my first record
>2,my second record
>[2021-01-07 11:35:30,443] ERROR Error when sending message to topic
>test-schemas with key: 1 bytes, value: 16 bytes with error:
>(org.apache.kafka.clients.producer.internals.ErrorLoggingCallback)
org.apache.kafka.common.InvalidRecordException: One or more records have been
rejected
3,my third record
>
{code}
*Consumer*
{code:java}
Vickys-MacBook-Pro:~ vicky$ kafka-console-consumer --bootstrap-server
localhost:9092 --from-beginning --topic test-schemas --property
print.key=trueVickys-MacBook-Pro:~ vicky$ kafka-console-consumer
--bootstrap-server localhost:9092 --from-beginning --topic test-schemas
--property print.key=true1
my first record3
my third record{code}
If the prompt was simply shown again after the error, it would solve the
usability problem.
cc: [~mjsax], [~guozhang], [~gshapira_impala_35cc], [~abhishekd.i...@gmail.com]
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