Added centralized logging

accounts.json

@@ -0,0 +1,4 @@
+{
+    "guest":"",
+    "user1":"secretpw"
+}

ssh_server.py

@@ -2,21 +2,25 @@
 # private key in it to use as a server host key. An SSH host certificate
 # can optionally be provided in the file ``ssh_host_key-cert.pub``.
 
-import asyncio, asyncssh, crypt, sys
+import asyncio
+import asyncssh
+import sys
+import json 
 from typing import Optional
-
+import logging
-passwords = {'guest': '',                 # guest account with no password
+import datetime
-             'user123': 'qV2iEadIGV2rw'   # password of 'secretpw'
-            }
 
 async def handle_client(process: asyncssh.SSHServerProcess) -> None:
+# This is the main loop for handling SSH client connections. 
+# Any user interaction should be done here.
+
     process.stdout.write('Welcome to my SSH server, %s!\n' %
                          process.get_extra_info('username'))
     
     try:
         async for line in process.stdin:
             line = line.rstrip('\n')
-            if line:
+            logging.info(f"INPUT: {line}")
             process.stdout.write('You entered: %s\n' % line)
     except asyncssh.BreakReceived:
         pass
@@ -25,36 +29,60 @@ async def handle_client(process: asyncssh.SSHServerProcess) -> None:
 
 class MySSHServer(asyncssh.SSHServer):
     def connection_made(self, conn: asyncssh.SSHServerConnection) -> None:
-        print('SSH connection received from %s.' %
+        logging.info(f"SSH connection received from {conn.get_extra_info('peername')[0]}.")
-                  conn.get_extra_info('peername')[0])
 
     def connection_lost(self, exc: Optional[Exception]) -> None:
         if exc:
             print('SSH connection error: ' + str(exc), file=sys.stderr)
+            logging.error('SSH connection error: ' + str(exc), file=sys.stderr)
+
         else:
             print('SSH connection closed.')
+            logging.info("SSH connection closed.")
 
     def begin_auth(self, username: str) -> bool:
         # If the user's password is the empty string, no auth is required
-        return passwords.get(username) != ''
+        return accounts.get(username) != ''
 
     def password_auth_supported(self) -> bool:
         return True
 
     def validate_password(self, username: str, password: str) -> bool:
-        pw = passwords.get(username, '*')
+        pw = accounts.get(username, '*')
-        return crypt.crypt(password, pw) == pw
+        return ((pw != '*') and (password == pw))
 
 async def start_server() -> None:
     await asyncssh.create_server(MySSHServer, '', 8022,
                                  server_host_keys=['ssh_host_key'],
                                  process_factory=handle_client)
 
-loop = asyncio.get_event_loop()
 
-try:
+def read_accounts() -> dict:
-    loop.run_until_complete(start_server())
+    accounts = dict()
-except (OSError, asyncssh.Error) as exc:
-    sys.exit('Error starting server: ' + str(exc))
 
+    with open('accounts.json', 'r') as f:
+        accounts = json.loads(f.read())
+
+    return accounts
+
+#### MAIN ####
+
+# Set up the logging
+logging.basicConfig(
+    filename="ssh_log.log", 
+    level=logging.INFO,
+    format="%(asctime)s %(levelname)s:%(message)s",
+    datefmt="%Y-%m-%d %H:%M:%S. %Z"
+)
+
+logging.Formatter.formatTime = (lambda self, record, datefmt=None: datetime.datetime.fromtimestamp(record.created, datetime.timezone.utc).astimezone().isoformat(sep="T",timespec="milliseconds"))
+
+# Read the valid accounts
+accounts = read_accounts()
+
+# Kick off the server!
+loop = asyncio.new_event_loop()
+asyncio.set_event_loop(loop)
+loop.run_until_complete(start_server())
 loop.run_forever()
+