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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?
2
Answers
By using the following table’s
schema(You can modify it according to your necessities):Try the following on your
FilterInsertsclass: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.
Create a table with column names same as the key of the dictionary of your pipeline you want to insert.
For example:
my output pipeline is a dictionary
{'age': 30, 'city': 'New York', 'name': 'John'}that I want to insert. So my table has a schema
{age:INTEGER,name:STRING,city:STRING}