Retry to connect to the API in case of failure

re2oapi/client.py

@@ -6,6 +6,7 @@ import stat
 import json
 import requests
 import smtplib
+import time
 from email.mime.multipart import MIMEMultipart
 from email.mime.text import MIMEText
 from requests.exceptions import HTTPError
@@ -27,7 +28,8 @@ class Re2oAPIClient:
     """
 
     def __init__(self, hostname, username, password, token_file=None,
-                 use_tls=True, log_level=logging.CRITICAL+10):
+                 use_tls=True, log_level=logging.CRITICAL+10, max_retries=0,
+                 wait_time=10):
         """Creates an API client.
 
         Args:
@@ -43,6 +45,10 @@ class Re2oAPIClient:
             (recommended for production). The default is `True`.
             log_level: Control the logging level to use. The default is
             `logging.CRITICAL+10`. So nothing is logged.
+            max_retries: The maximum number of retries if the client cannot
+            connect to the API. The default is 0.
+            wait_time: The time to wait between two API tests. It is ignored if
+            `max_retries` is 0. The default value is 10 seconds.
 
         Raises:
             requests.exceptions.ConnectionError: Unable to resolve the
@@ -76,6 +82,9 @@ class Re2oAPIClient:
         self.hostname = hostname
         self._username = username
         self._password = password
+
+        self._check_api(max_retries, wait_time)
+
         # Try to fetch token from token file else get a new one from the
         # server
         try:
@@ -83,6 +92,23 @@ class Re2oAPIClient:
         except exceptions.APIClientGenericError:
             self._force_renew_token()
 
+    def _check_api(self, max_retries, wait_time):
+        """Checks if the API is responding to our requests"""
+        api_root = self.get_url_for("")
+        self.log.debug(f'Trying to connect to "{api_root}"')
+        for i in range(max_retries + 1):
+            try:
+                r = requests.get(api_root)
+                r.raise_for_status()
+                return
+            except Exception as e:
+                self.log.warning(f"[{i}/{max_retries}] Unable to get an answer from {api_root}: {e}")
+
+                if i == max_retries:
+                    raise e
+                else:
+                    time.sleep(wait_time)
+
     @property
     def need_renew_token(self):
         """The token needs to be renewed.