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Posted to user@spark.apache.org by Something Something <ma...@gmail.com> on 2020/03/04 02:02:30 UTC

Stateful Spark Streaming: Required attribute 'value' not found

In a Stateful Spark Streaming application I am writing the 'OutputRow' in
the 'updateAcrossEvents' but I keep getting this error (*Required attribute
'value' not found*) while it's trying to write to Kafka. I know from the
documentation that 'value' attribute needs to be set but how do I do that
in the 'Stateful Structured Streaming'? Where & how do I add this 'value'
attribute in the following code? *Note: I am using Spark 2.3.1*

withEventTime
      .as[R00tJsonObject]
      .withWatermark("event_time", "5 minutes")
      .groupByKey(row => (row.value.Id, row.value.time.toString, row.value.cId))
      .mapGroupsWithState(GroupStateTimeout.EventTimeTimeout)(updateAcrossEvents)
      .writeStream
      .format("kafka")
      .option("kafka.bootstrap.servers", "localhost:9092")
      .option("topic", "myTopic")
      .option("checkpointLocation", "/Users/username/checkpointLocation")
      .outputMode("update")
      .start()
      .awaitTermination()

Re: Stateful Spark Streaming: Required attribute 'value' not found

Posted by Something Something <ma...@gmail.com>.

By simply adding 'toJSON' before 'writeStream' the problem was fixed. Maybe
it will help someone.

On Tue, Mar 3, 2020 at 6:02 PM Something Something <ma...@gmail.com>
wrote:

> In a Stateful Spark Streaming application I am writing the 'OutputRow' in
> the 'updateAcrossEvents' but I keep getting this error (*Required
> attribute 'value' not found*) while it's trying to write to Kafka. I know
> from the documentation that 'value' attribute needs to be set but how do I
> do that in the 'Stateful Structured Streaming'? Where & how do I add this
> 'value' attribute in the following code? *Note: I am using Spark 2.3.1*
>
> withEventTime
>       .as[R00tJsonObject]
>       .withWatermark("event_time", "5 minutes")
>       .groupByKey(row => (row.value.Id, row.value.time.toString, row.value.cId))
>       .mapGroupsWithState(GroupStateTimeout.EventTimeTimeout)(updateAcrossEvents)
>       .writeStream
>       .format("kafka")
>       .option("kafka.bootstrap.servers", "localhost:9092")
>       .option("topic", "myTopic")
>       .option("checkpointLocation", "/Users/username/checkpointLocation")
>       .outputMode("update")
>       .start()
>       .awaitTermination()
>
>