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wubloader/common/common/googleapis.py

68 lines
2.3 KiB
Python

import time
import logging
import gevent
from .requests import InstrumentedSession
# Wraps all requests in some metric collection
requests = InstrumentedSession()
class GoogleAPIClient(object):
"""Manages access to google apis and maintains an active access token.
Make calls using client.request(), which is a wrapper for requests.request().
"""
ACCESS_TOKEN_ERROR_RETRY_INTERVAL = 10
# Refresh token 10min before it expires (it normally lasts an hour)
ACCESS_TOKEN_REFRESH_TIME_BEFORE_EXPIRY = 600
def __init__(self, client_id, client_secret, refresh_token):
self.client_id = client_id
self.client_secret = client_secret
self.refresh_token = refresh_token
self._first_get_access_token = gevent.spawn(self.get_access_token)
@property
def access_token(self):
"""Blocks if access token unavailable yet"""
self._first_get_access_token.join()
return self._access_token
def get_access_token(self):
"""Authenticates against google's API and retrieves a token we will use in
subsequent requests.
This function gets called automatically when needed, there should be no need to call it
yourself."""
while True:
try:
start_time = time.time()
resp = requests.post('https://www.googleapis.com/oauth2/v4/token', data={
'client_id': self.client_id,
'client_secret': self.client_secret,
'refresh_token': self.refresh_token,
'grant_type': 'refresh_token',
}, metric_name='get_access_token')
resp.raise_for_status()
data = resp.json()
self._access_token = data['access_token']
expires_in = (start_time + data['expires_in']) - time.time()
if expires_in < self.ACCESS_TOKEN_REFRESH_TIME_BEFORE_EXPIRY:
self.logger.warning("Access token expires in {}s, less than normal leeway time of {}s".format(
expires_in, self.ACCESS_TOKEN_REFRESH_TIME_BEFORE_EXPIRY,
))
gevent.spawn_later(expires_in - self.ACCESS_TOKEN_REFRESH_TIME_BEFORE_EXPIRY, self.get_access_token)
except Exception:
logging.exception("Failed to fetch access token, retrying")
gevent.sleep(self.ACCESS_TOKEN_ERROR_RETRY_INTERVAL)
else:
break
def request(self, method, url, headers={}, **kwargs):
# merge in auth header
headers = dict(headers, Authorization='Bearer {}'.format(self.access_token))
return requests.request(method, url, headers=headers, **kwargs)