Approve CodePipeline approval action with Lambda function

approve_release.py

import boto3

def lambda_handler(event, context):
    pipeline_name=event['PIPELINE_NAME']
    stage_name=event['STAGE_NAME']
    action_name=event['ACTION_NAME']

    cp = boto3.client('codepipeline')
    state = cp.get_pipeline_state(name=pipeline_name)

    for stage_state in state['stageStates']:
        if stage_state['stageName'] == stage_name:
            stage = stage_state 

    for action_state in stage['actionStates']:
        if action_state['actionName'] == action_name:
            action = action_state 

    token = action['latestExecution']['token']

    cp.put_approval_result(
        pipelineName=pipeline_name,
        stageName=stage_name,
        actionName=action_name,
        result={
            'summary': 'ok',
            'status': 'Approved'
        },
        token=token
    )

    return 'Completed.'