Merge pull request #88 from swails/feature/improve-retries

Improve retry logic

wideq/core.py

@@ -9,6 +9,8 @@ import datetime
 import requests
 import logging
 from typing import Any, Dict, List, Tuple
+from requests.adapters import HTTPAdapter
+from requests.packages.urllib3.util.retry import Retry
 
 GATEWAY_URL = 'https://kic.lgthinq.com:46030/api/common/gatewayUriList'
 APP_KEY = 'wideq'
@@ -21,6 +23,9 @@ OAUTH_CLIENT_KEY = 'LGAO221A02'
 DATE_FORMAT = '%a, %d %b %Y %H:%M:%S +0000'
 DEFAULT_COUNTRY = 'US'
 DEFAULT_LANGUAGE = 'en-US'
+NUM_RETRIES = 5  # Anecdotally this seems sufficient.
+BACKOFF_FACTOR = 0.5
+STATUS_FORCELIST = (502, 503, 504)
 
 
 def get_wideq_logger() -> logging.Logger:
@@ -59,6 +64,26 @@ def get_wideq_logger() -> logging.Logger:
 LOGGER = get_wideq_logger()
 
 
+def get_retry_session():
+    # See https://www.peterbe.com/plog/best-practice-with-retries-with-requests
+    # for the source of this retry mechanism
+    session = requests.Session()
+    retry = Retry(
+        total=NUM_RETRIES,
+        read=NUM_RETRIES,
+        connect=NUM_RETRIES,
+        backoff_factor=BACKOFF_FACTOR,
+        status_forcelist=STATUS_FORCELIST,
+    )
+    adapter = HTTPAdapter(max_retries=retry)
+    session.mount('http://', adapter)
+    session.mount('https://', adapter)
+    return session
+
+
+SESSION = get_retry_session()
+
+
 def set_log_level(level: int):
     logger = get_wideq_logger()
     logger.setLevel(level)
@@ -163,7 +188,6 @@ def lgedm_post(url, data=None, access_token=None, session_id=None):
     authenticated requests. They are not required, for example, to load
     the gateway server data or to start a session.
     """
-
     headers = {
         'x-thinq-application-key': APP_KEY,
         'x-thinq-security-key': SECURITY_KEY,
@@ -174,7 +198,7 @@ def lgedm_post(url, data=None, access_token=None, session_id=None):
     if session_id:
         headers['x-thinq-jsessionId'] = session_id
 
-    res = requests.post(url, json={DATA_ROOT: data}, headers=headers)
+    res = SESSION.post(url, json={DATA_ROOT: data}, headers=headers)
     out = res.json()[DATA_ROOT]
 
     # Check for API errors.
@@ -266,7 +290,7 @@ def refresh_auth(oauth_root, refresh_token):
         'Accept': 'application/json',
     }
 
-    res = requests.post(token_url, data=data, headers=headers)
+    res = SESSION.post(token_url, data=data, headers=headers)
     res_data = res.json()
 
     if res_data['status'] != 1: