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https://issues.apache.org/jira/browse/KAFKA-7052?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17032488#comment-17032488
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Randall Hauch commented on KAFKA-7052:
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Thanks for the discussion, everyone. As soon as we introduce a configuration
option on a Connect-provided SMT, we need a KIP and we can't backport the
change.
I would suggestion the following:
# One PR to improve the error message per [~rmoff]'s earlier comment (e.g.,
"ExtractField : field 'id' not found in Key") but otherwise not change the
behavior. Or, we make the message better and we decide that "skip" is an
appropriate fix rather than an NPE; this may need more discussion, but I think
NPE is a bad UX and probably rarely useful. This would be able to be merged on
trunk and backported to 2-3 branches (standard practice).
# Create a new Jira issue and small KIP and another PR to add the proposed
ExtractField configuration property, such as
"{{behavior.on.non.existant.field}} = {{(fail|drop|skip)}}". Note I'm
suggesting using "skip" rather than "passon" to keep things simple.
[~gunnar.morling]'s PR would apply to this new Jira issue and KIP rather than
to this issue.
# Create a new Jira issue and KIP to define an optional topic filter property
for each transformation that would specify a regex pattern matching the topics
to which the SMT should apply, and defaulting to ".*" to maintain the current
behavior. I'm not sure how feasible this will be to ensure it never clashes
with SMT-specific properties, but it's worth investigating.
Important: We've already missed the KIP acceptance deadline for AK 2.5, so the
earliest #2 and #3 could appear is AK 2.6.
WDYT?
> ExtractField SMT throws NPE - needs clearer error message
> ---------------------------------------------------------
>
> Key: KAFKA-7052
> URL: https://issues.apache.org/jira/browse/KAFKA-7052
> Project: Kafka
> Issue Type: Improvement
> Components: KafkaConnect
> Reporter: Robin Moffatt
> Priority: Major
>
> With the following Single Message Transform:
> {code:java}
> "transforms.ExtractId.type":"org.apache.kafka.connect.transforms.ExtractField$Key",
> "transforms.ExtractId.field":"id"{code}
> Kafka Connect errors with :
> {code:java}
> java.lang.NullPointerException
> at
> org.apache.kafka.connect.transforms.ExtractField.apply(ExtractField.java:61)
> at
> org.apache.kafka.connect.runtime.TransformationChain.apply(TransformationChain.java:38){code}
> There should be a better error message here, identifying the reason for the
> NPE.
> Version: Confluent Platform 4.1.1
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