Nsryjdtyk

My sample data is in json format and looks like:

{

  "metadata": {

    "action": "insert",

    "type": "export",

    "version": 1,

    "timestamp": "2018-11-23T09:17:59.048-08:00"

  },

  "data": {

    "attr1": 61,

    "day": "2018-11-22",

    "pin": "2C49956",

    "CDP": 0,

    "DP": 0,

    "VD": 0,

    "seo": 0,

    "dir": 0,

    "other": 0,

    "at": 0

  }

}

This is in a flat file and the objective is to run a dataflow pipeline in batch mode to insert the data into bigquery table. In one of the transformations where I want to take timestamp from the metadata and add it as a key value pair in the data section, I am getting the error from dataflow saying 'unicode object has no attribute 'items'.

The code looks as below:

import collections

import json

import argparse

import logging

from datetime import datetime

import apache_beam as beam

from apache_beam.options.pipeline_options import PipelineOptions, GoogleCloudOptions, StandardOptions, SetupOptions, 

    WorkerOptions

from apache_beam.io.gcp import bigquery





# Creating options object

def create_options(argv):

    # pipeline options

    options = PipelineOptions()

    google_cloud_options = options.view_as(GoogleCloudOptions)

    google_cloud_options.project = 'something'

    google_cloud_options.job_name = datetime.now().strftime('somename')

    google_cloud_options.staging_location = 'some_loc'

    google_cloud_options.temp_location = 'another_loc'

    options.view_as(StandardOptions).runner = 'DirectRunner'

    options.view_as(SetupOptions).save_main_session = True

    options.view_as(WorkerOptions).machine_type = 'n1-standard-1'

    return options



    class PrepareData(beam.DoFn):

        """

        ParDo function to create a dictionary of data for downstream consumption

        """



        def process(self, element):

            data = json.loads(element)

            modified_data = {"action": data["metadata"]["action"], "timestamp": data["metadata"]["timestamp"], "data": data}

            return [modified_data]





    class FilterInserts(beam.DoFn):

        """

        Filter data for inserts

        """



        def process(self, element):

            if element["action"] == "insert":

                element['data']['data']['timestamp'] = element['timestamp']

                # for dict in element["data"]["data"]:

                #     dict["timestamp"] = element["timestamp"]

                return element["data"]["data"]





    def run_pipe(options, argv):

        """

        Creating pipelines

        """

        p = beam.Pipeline(options=options)



        main_pipe =p | 'PREPARE_DATA' >> beam.io.ReadFromText('/home/Downloads/sample_1') | beam.ParDo(PrepareData())



        """ Separating pipes for various actions """

        insert_pipe= main_pipe | beam.ParDo(FilterInserts())



        """

        Inserts--> sinking to BQ

        """

        insert_pipe | 'INSERT' >> beam.io.WriteToBigQuery(

            project='some-data-warehouse',

            dataset='sample_data',

            table='sample',

            write_disposition='WRITE_APPEND',

            create_disposition='CREATE_IF_NEEDED')





        p.run()





    def main():

        """

        Main function to drive the run

        :return: errors if any

        """

        parser = argparse.ArgumentParser()

        args = parser.parse_args()

        try:

            # create options

            opt = create_options(argv=args)

            # run pipeline

            run_pipe(opt, argv=args)

        except Exception as e:

            logging.error('Pipeline failed with error : %s', e)

            raise Exception('Pipeline failed with error : %s', e)





    if __name__ == "__main__":

        main()

I am running this on direct runner to test on local but i get the same error even if i change the runner to dataflow-runner.
The error message is:

Exception: ('Pipeline failed with error : %s', AttributeError(u"'unicode' object has no attribute 'items' [while running 'INSERT/WriteToBigQuery']",))

Can anyone help me figure out what's going wrong and how i can fix this?

By using the following table's schema (You can modify it according to your necessities):

schema = 'VD:INTEGER,pin:STRING,timestamp:STRING,other:INTEGER,CDP:INTEGER,dir:INTEGER,attr1:INTEGER,seo:INTEGER,day:STRING,DP:INTEGER,at:INTEGER'

Try the following on your FilterInserts class:

class FilterInserts(beam.DoFn):

    """

    Filter data for inserts

    """



    def process(self, element):

        if element["action"] == "insert":

            element['data']['data']['timestamp'] = element['timestamp']



            return [{

            'VD': element['data']['data']['VD'],

            'pin': element['data']['data']['pin'],

            'timestamp': element['data']['data']['timestamp'],

            'other': element['data']['data']['other'],

            'CDP': element['data']['data']['CDP'],

            'dir': element['data']['data']['dir'],

            'attr1' : element['data']['data']['attr1'],

            'seo' : element['data']['data']['seo'],

            'day' : element['data']['data']['day'],

            'DP' : element['data']['data']['DP'],

            'at' : element['data']['data']['at'],

            }]

The issue happens since you need to send a Key Value array to BigQuery, and you were sending a JSON dictionary with unicode strings.

Hope it helps.