This class will get consumer config properties via
configure() method, including clientId assigned
by KafkaConsumer if not specified in the consumer config. The interceptor implementation needs to be aware that it will be
sharing consumer config namespace with other interceptors and serializers, and ensure that there are no conflicts.
Exceptions thrown by ConsumerInterceptor methods will be caught, logged, but not propagated further. As a result, if the user configures the interceptor with the wrong key and value type parameters, the consumer will not throw an exception, just log the errors.
ConsumerInterceptor callbacks are called from the same thread that invokes
ClusterResourceListener to receive cluster metadata once it's available. Please see the class documentation for ClusterResourceListener for more information.
onConsumeThis is called just before the records are returned by
This method is allowed to modify consumer records, in which case the new records will be returned. There is no limitation on number of records that could be returned from this method. I.e., the interceptor can filter the records or generate new records.
Any exception thrown by this method will be caught by the caller, logged, but not propagated to the client.
Since the consumer may run multiple interceptors, a particular interceptor's onConsume() callback will be called in the order specified by
ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG. The first interceptor in the list gets the consumed records, the following interceptor will be passed the records returned by the previous interceptor, and so on. Since interceptors are allowed to modify records, interceptors may potentially get the records already modified by other interceptors. However, building a pipeline of mutable interceptors that depend on the output of the previous interceptor is discouraged, because of potential side-effects caused by interceptors potentially failing to modify the record and throwing an exception. If one of the interceptors in the list throws an exception from onConsume(), the exception is caught, logged, and the next interceptor is called with the records returned by the last successful interceptor in the list, or otherwise the original consumed records.
records- records to be consumed by the client or records returned by the previous interceptors in the list.
- records that are either modified by the interceptor or same as records passed to this method.
onCommitThis is called when offsets get committed.
Any exception thrown by this method will be ignored by the caller.
offsets- A map of offsets by partition with associated metadata
closevoid close()This is called when interceptor is closed