export a simple report of Jenkins credential usage

export.py

import csv
import requests

auth = ('username', 'password')

API_URL = 'http://jenkins.host/credentials/store/system/api/json?depth=3&pretty=1'

response = requests.get(API_URL, auth=auth)

data = response.json()

with open('filename.csv', 'w') as csvfile:
    writer = csv.DictWriter(
        csvfile, fieldnames=['displayName', 'description', 'usage'],
        extrasaction='ignore')
    writer.writeheader()
    for domain, domain_data in data['domains'].items():
        for cred_data in domain_data['credentials']:
            usage = 0
            if cred_data['fingerprint']:
                usage = len(cred_data['fingerprint'].get('usage'))
            cred_data['usage'] = usage

            writer.writerow(cred_data)