AWS region in AWS Glue

How can I get the region in which the current Glue job is executing?

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When the Glue job starts executing, I see the output

Detected region eu-central-1.

In AWS Lambda, I can use the following lines to fetch the current region:

import os
region = os.environ['AWS_REGION']

However, it seems like the AWS_REGION environment variable is not present in Glue and therefore a KeyError is raised:

KeyError: 'AWS_REGION'

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The reason why I need the region is I am trying to fetch all databases and tables as described in this question and I do not want to hard code the region when creating the boto client.

Answer

One option is to pass the AWS_REGION as a job parameter. For example, if you trigger the job from Lambda:

import os

response = client.start_job_run(
    JobName = 'a_job_name',
    Arguments = {'--AWS_REGION': os.environ['AWS_REGION'] } 
)

Alternatively, if you define your jobs using the AWS::Glue::Job CloudFormation resource:

GlueJob:
  Type: AWS::Glue::Job
  Properties:
    Role: !Ref GlueRole
    DefaultArguments:
      "--AWS_REGION": !Sub "${AWS::Region}"
    Command:
      ScriptLocation: !Sub s3://${GlueScriptBucket}/glue-job.py
      Name: glueetl

Then you can extract the AWS_REGION parameter in your job code using getResolvedOptions:

import sys
from awsglue.utils import getResolvedOptions

args = getResolvedOptions(sys.argv, ['AWS_REGION'])
print('region', args['AWS_REGION'])