feat: removed check_port and made command optional

Author: ryshoooo

jupyter_server_proxy/config.py

@@ -17,7 +17,7 @@
 except ImportError:
     from .utils import Callable
 
-def _make_serverproxy_handler(name, command, environment, timeout, absolute_url, port, check_port, mappath, request_headers_override, rewrite_response):
+def _make_serverproxy_handler(name, command, environment, timeout, absolute_url, port, mappath, request_headers_override, rewrite_response):
     """
     Create a SuperviseAndProxyHandler subclass with given parameters
     """
@@ -26,10 +26,10 @@ class _Proxy(SuperviseAndProxyHandler):
         def __init__(self, *args, **kwargs):
             super().__init__(*args, **kwargs)
             self.name = name
+            self.command = command
             self.proxy_base = name
             self.absolute_url = absolute_url
             self.requested_port = port
-            self.check_port = check_port
             self.mappath = mappath
             self.rewrite_response = rewrite_response
 
@@ -63,7 +63,7 @@ def _realize_rendered_template(self, attribute):
             return self._render_template(attribute)
 
         def get_cmd(self):
-            return self._realize_rendered_template(command)
+            return self._realize_rendered_template(self.command)
 
         def get_env(self):
             return self._realize_rendered_template(environment)
@@ -115,20 +115,19 @@ def make_handlers(base_url, server_processes):
 
 LauncherEntry = namedtuple('LauncherEntry', ['enabled', 'icon_path', 'title', 'path_info'])
 ServerProcess = namedtuple('ServerProcess', [
-    'name', 'command', 'environment', 'timeout', 'absolute_url', 'port', 'check_port',
+    'name', 'command', 'environment', 'timeout', 'absolute_url', 'port',
     'mappath', 'launcher_entry', 'new_browser_tab', 'request_headers_override', 'rewrite_response',
 ])
 
 def make_server_process(name, server_process_config, serverproxy_config):
     le = server_process_config.get('launcher_entry', {})
     return ServerProcess(
         name=name,
-        command=server_process_config['command'],
+        command=server_process_config.get('command', list()),
         environment=server_process_config.get('environment', {}),
         timeout=server_process_config.get('timeout', 5),
         absolute_url=server_process_config.get('absolute_url', False),
         port=server_process_config.get('port', 0),
-        check_port=server_process_config.get('check_port', True),
         mappath=server_process_config.get('mappath', {}),
         launcher_entry=LauncherEntry(
             enabled=le.get('enabled', True),
@@ -155,12 +154,16 @@ class ServerProxy(Configurable):
 
         Value should be a dictionary with the following keys:
           command
-            A list of strings that should be the full command to be executed.
+            An optional list of strings that should be the full command to be executed.
             The optional template arguments {{port}} and {{base_url}} will be substituted with the
             port the process should listen on and the base-url of the notebook.
 
             Could also be a callable. It should return a list.
 
+            If the command is not specified or is an empty list, it is assumed the process is already
+            running, therefore the port checking is skipped and the proxy is set up on the specified
+            port.
+
           environment
             A dictionary of environment variable mappings. As with the command
             traitlet, {{port}} and {{base_url}} will be substituted.
@@ -177,10 +180,6 @@ class ServerProxy(Configurable):
           port
             Set the port that the service will listen on. The default is to automatically select an unused port.
 
-          check_port
-            Enable/Disable port availability check. If enabled and port is not available, the proxy will
-            raise an exception. If disabled, the port availability check is skipped. Default is True.
-
           mappath
             Map request paths to proxied paths.
             Either a dictionary of request paths to proxied paths,

jupyter_server_proxy/handlers.py

@@ -558,7 +558,7 @@ class SuperviseAndProxyHandler(LocalProxyHandler):
     def __init__(self, *args, **kwargs):
         self.requested_port = 0
         self.mappath = {}
-        self.check_port = True
+        self.command = list()
         super().__init__(*args, **kwargs)
 
     def initialize(self, state):
@@ -574,7 +574,7 @@ def port(self):
         Allocate either the requested port or a random empty port for use by
         application
         """
-        if 'port' not in self.state and self.check_port:
+        if 'port' not in self.state and self.command:
             sock = socket.socket()
             sock.bind(('', self.requested_port))
             self.state['port'] = sock.getsockname()[1]