Fix the output of omero_user_token get utility

The introduction of the login() functionality allowed to consume the
connection logic as an API but removed the ability to print the
token when invoking the command-line.
This splits the logic into two calls: get_token() and login()

Author: sbesson

omero_user_token/__init__.py

@@ -66,34 +66,41 @@ def setter(server, port, user, password, time_to_idle):
         client.closeSession()
 
 
-def login():
+def get_token():
     """
-    Returns an omero.client object from the current user token.  The
-    session the token refers to has had a join attempt made upon it.  If
-    the token file does not exist a FileNotFoundError will be raised.
+    Returns the current user token
+    Raises FileNotFoundError if the token file does not exist
     """
-    token_path = assert_and_get_token_path()
-    with open(token_path, 'r') as token_file:
-        token = token_file.read().strip()
-        omero_session_key = token[:token.find('@')]
-        host, port = token[token.find('@') + 1:].split(':')
-        client = omero.client(host, int(port))
-        try:
-            session = client.joinSession(omero_session_key)
-            session.detachOnDestroy()
-        except Exception:
-            pass
-        return client
+    with open(assert_and_get_token_path(), 'r') as token_path:
+        return token_path.read().strip()
+
+
+def login(token):
+    """
+    Returns an omero.client object from a valid token.  The
+    session the token refers to has had a join attempt made upon it.
+    """
+    omero_session_key = token[:token.find('@')]
+    host, port = token[token.find('@') + 1:].split(':')
+    client = omero.client(host, int(port))
+    try:
+        session = client.joinSession(omero_session_key)
+        session.detachOnDestroy()
+    except Exception:
+        pass
+    return client
 
 
 def getter():
     try:
-        client = login()
+        token = get_token()
+        client = login(token)
         try:
             client.getSession()
         except Exception:
             sys.exit('ERROR: Token is invalid!')
         finally:
             client.closeSession()
+        return token
     except FileNotFoundError:
         sys.exit('ERROR: No token available, `omero_user_token set` required!')