Dealing with two topics in Spark Structured Streaming

[Mich Talebzadeh]

Hi,


I am dealing with two topics in SSS.


Topic "md" returns market data values as per


            result = streamingDataFrame.select( \

                     col("parsed_value.rowkey").alias("rowkey") \

                   , col("parsed_value.ticker").alias("ticker") \

                   , col("parsed_value.timeissued").alias("timeissued") \

                   , col("parsed_value.price").alias("price")). \

                     writeStream. \

                     outputMode('append'). \

                     option("truncate", "false"). \

                     foreachBatch(*sendToSink*). \

                     trigger(processingTime='30 seconds'). \

Topic "newtopic" returns one row including status column

           newtopicResult = streamingNewtopic.select( \
                     col("newtopic_value.uuid").alias("uuid") \
                   , col("newtopic_value.timecreated").alias("timecreated")
\
                   , col("newtopic_value.status").alias("status")). \
                     writeStream. \
                     outputMode('append'). \
                     option("truncate", "false"). \
                     foreachBatch(*sendToControl*). \
                     trigger(processingTime='2 seconds'). \
                     start()

The method sendToSink writes values to a database BigQuery

def sendToSink(df, batchId):
    if(len(df.take(1))) > 0:
        print(f"""{batchId}""")
        df.show(100)
        df. persist()
        # write to BigQuery batch table
        s.writeTableToBQ(df, "append",
config['MDVariables']['targetDataset'],config['MDVariables']['targetTable'])
        df.unpersist()
    else:
        print("DataFrame is empty")

The second method simply gets value for status column

def sendToControl(dfnewtopic, batchId):
    if(len(dfnewtopic.take(1))) > 0:
        print(f"""newtopic batchId is {batchId}""")
       * status = dfnewtopic.select(col("status")).collect()[0][0]*
    else:
        print("DataFrame newtopic is empty")

I need to be able to check the status value from the sendToControl method
in the sendToSink method. Note that status values may be changing as per
streaming. What would be the best approach?

Thanks


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