Add timeout for requests.post() operation

Like all network operations, performing the POST request may fail for various
reasons. When no response from the remote end is received, a requests.post()
call may never return, leading to an unbounded increase in the sender queue.

To remedy such situations let's add a timeout argument to the requests call and
make it configurable, to be adaptable for different environments.

For more information see
https://2.python-requests.org/en/master/user/quickstart/#timeouts

logzio/handler.py

@@ -17,7 +17,8 @@ class LogzioHandler(logging.Handler):
                  logs_drain_timeout=3,
                  url="https://listener.logz.io:8071",
                  debug=False,
-                 backup_logs=True):
+                 backup_logs=True,
+                 network_timeout=10.0):
 
         if not token:
             raise LogzioException('Logz.io Token must be provided')
@@ -29,7 +30,8 @@ class LogzioHandler(logging.Handler):
             url=url,
             logs_drain_timeout=logs_drain_timeout,
             debug=debug,
-            backup_logs=backup_logs)
+            backup_logs=backup_logs,
+            network_timeout=network_timeout)
         logging.Handler.__init__(self)
 
     def extra_fields(self, message):

logzio/sender.py

@@ -33,12 +33,14 @@ class LogzioSender:
                  token, url='https://listener.logz.io:8071',
                  logs_drain_timeout=5,
                  debug=False,
-                 backup_logs=True):
+                 backup_logs=True,
+                 network_timeout=10.0):
         self.token = token
         self.url = '{}/?token={}'.format(url, token)
         self.logs_drain_timeout = logs_drain_timeout
         self.logger = get_logger(debug)
         self.backup_logs = backup_logs
+        self.network_timeout = network_timeout
 
         # Function to see if the main thread is alive
         self.is_main_thread_active = lambda: any(
@@ -104,7 +106,8 @@ class LogzioSender:
                 should_retry = False
                 try:
                     response = requests.post(
-                        self.url, headers=headers, data='\n'.join(logs_list))
+                        self.url, headers=headers, data='\n'.join(logs_list),
+                        timeout=self.network_timeout)
                     if response.status_code != 200:
                         if response.status_code == 400:
                             self.logger.info(