src: add user session detection implementation

Detect user login and logout for Linux and Windows.

Report an active interactive session through the /refresh response
so a new ogserver instance can update the session status.

Poll the session change in 5 second intervals in a thread. Use the
same event socket previously used by the old session detection
mechanism to notify a session change.

Use the method check_interactive_session_change in each
ogOperations.py to report the session status.
Return values:
	None: no session changes are found
	True: login
	False: logout

Windows
Verify if psutil.users() has any value.

Linux
Verify all the psutil.users() asociated to a terminal.

1 files changed, 23 insertions, 1 deletions

diff --git a/src/ogClient.py b/src/ogClient.py
index 51aa33b..2635a3f 100644
--- a/src/ogClient.py
+++ b/src/ogClient.py
@@ -6,6 +6,7 @@
 # Free Software Foundation; either version 3 of the License, or
 # (at your option) any later version.
 
+import threading
 import errno
 import select
 import socket
@@ -26,6 +27,8 @@ class State(Enum):
 
 class ogClient:
 	OG_PATH = '/opt/opengnsys/'
+	SESSION_POLL_INTERVAL = 5
+	EVENT_SOCKET_PORT = 55885
 
 	def __init__(self, config):
 		self.CONFIG = config
@@ -36,7 +39,7 @@ class ogClient:
 		if self.mode in {'linux', 'windows'}:
 			self.event_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
 			self.event_sock.setblocking(0)
-			self.event_sock.bind(('127.0.0.1', 55885))
+			self.event_sock.bind(('127.0.0.1', ogClient.EVENT_SOCKET_PORT))
 		else:
 			self.event_sock = None
 
@@ -49,6 +52,25 @@ class ogClient:
 		self.ogrest = ogRest(self.CONFIG)
 		self.seq = None
 
+		self.session_check_thread = threading.Thread(target=self._session_check_loop, daemon=True)
+		self.session_check_thread.start()
+
+	def _session_check_loop(self):
+		while True:
+			session_status = self.ogrest.check_interactive_session_change()
+			if session_status is True:
+				message = "session start user"
+			elif session_status is False:
+				message = "session stop user"
+			else:
+				message = None
+
+			if message:
+				self.event_sock.sendto(message.encode('utf-8'),
+				                       ('127.0.0.1', ogClient.EVENT_SOCKET_PORT))
+
+			time.sleep(ogClient.SESSION_POLL_INTERVAL)
+
 	def get_socket(self):
 		return self.sock