How to parse 2 json files in Apache beam - json

Question

I have 2 json configuration files to read and want to assign there values to variables. I am creating a data flow job using apache beam but unable to parse those files and assign there values to a variable.
config1.json - { "bucket_name": "mybucket"}
config2.json - { "dataset_name": "mydataset"}
This is the pipeline statements ---- I tried with one JSON file first but even that is not working
with beam.Pipeline(options=pipeline_options) as pipeline:
steps = (pipeline
| "Getdata" >> beam.io.ReadFromText(custom_options.configfile)
| "CUSTOM JSON PARSE" >> beam.ParDo(custom_json_parser(custom_options.configfile))
| "write to GCS" >> beam.io.WriteToText('gs://mynewbucket/outputfile.txt')
)
result = pipeline.run()
result.wait_until_finish()
I also tried creating a function to parse atleast one file. This is a sample method I created but it did not work.
class custom_json_parser(beam.DoFn):
import apache_beam as beam
from apache_beam.io.gcp import gcsio
import logging
def __init__(self, configfile):
self.configfile = configfile
def process(self, configfile):
logging.info("JSON PARSING STARTED")
with beam.io.gcp.gcsio.GcsIO().open(self.configfile, 'r') as f:
for line in f:
data = json.loads(line)
bucket = data.get('bucket_name')
dataset = data.get('dataset_name') ```
Can someone please suggest the best method to resolve this issue in apache beam?
Thanks in Advance

Answer 1

If you need to read only once your files in the pipeline, don't read them in the pipeline, but before running it.
Read the files from GCS
Parse the file and put the useful content in the pipeline options map
Run your pipeline and use the data from the options
EDIT 1
You can use this piece of code to load the file and read it, before your pipeline. Simple Python, standard GCS libraries.
from google.cloud import storage
import json
client = storage.Client()
bucket = client.get_bucket('your-bucket')
blob = bucket.get_blob("name.json")
json_data = blob.download_as_string().decode('UTF-8')
print(json_data) # print -> {"name": "works!!"}
print(json.loads(json_data)["name"]) # print -> works!!

Answer 2

You can try following code snippet: -
Function to Parse File
class custom_json_parser(beam.DoFn):
def process(self, element):
logging.info(element)
data = json.loads(element)
bucket = data.get('bucket_name')
dataset = data.get('dataset_name')
return [{"bucket": bucket , "dataset": dataset }]
Over Pipeline you can call function
with beam.Pipeline(options=pipeline_options) as pipeline:
steps = (pipeline
| "Getdata" >> beam.io.ReadFromText(custom_options.configfile)
| "CUSTOM JSON PARSE" >> beam.ParDo(custom_json_parser())
| "write to GCS" >> beam.io.WriteToText('gs://mynewbucket/outputfile.txt')
)
result = pipeline.run()
result.wait_until_finish()
It will work.