Allow bokeh server to be started on a Thread

panel/util.py

@@ -8,6 +8,7 @@
 import inspect
 import numbers
 import hashlib
+import threading
 
 from collections import defaultdict, MutableSequence, MutableMapping, OrderedDict
 from datetime import datetime
@@ -213,6 +214,30 @@ def __call__(self, pname):
         return pname
 
 
+class StoppableThread(threading.Thread):
+    """Thread class with a stop() method."""
+
+    def __init__(self, io_loop=None, timeout=1000, **kwargs):
+        from tornado import ioloop
+        super(StoppableThread, self).__init__(**kwargs)
+        self._stop_event = threading.Event()
+        self.io_loop = io_loop
+        self._cb = ioloop.PeriodicCallback(self._check_stopped, timeout)
+        self._cb.start()
+
+    def _check_stopped(self):
+        if self.stopped:
+            self._cb.stop()
+            self.io_loop.stop()
+
+    def stop(self):
+        self._stop_event.set()
+
+    @property
+    def stopped(self):
+        return self._stop_event.is_set()
+
+
 ################################
 # Display and update utilities #
 ################################

panel/viewable.py

@@ -325,7 +325,24 @@ def app(self, notebook_url="localhost:8888"):
         """
         show(self._modify_doc, notebook_url=notebook_url)
 
-    def show(self, port=0, websocket_origin=None):
+    def _start_server(self, app, loop, port, websocket_origin):
+        if websocket_origin and not isinstance(websocket_origin, list):
+            websocket_origin = [websocket_origin]
+        opts = dict(allow_websocket_origin=websocket_origin) if websocket_origin else {}
+        loop.make_current()
+        opts['io_loop'] = loop
+        server = Server({'/': app}, port=port, **opts)
+        def show_callback():
+            server.show('/')
+        server.io_loop.add_callback(show_callback)
+        server.start()
+        try:
+            loop.start()
+        except RuntimeError:
+            pass
+        return server
+
+    def show(self, port=0, websocket_origin=None, threaded=False):
         """
         Starts a bokeh server and displays the Viewable in a new tab
 
@@ -340,27 +357,31 @@ def show(self, port=0, websocket_origin=None):
             an external web site.
 
             If None, "localhost" is used.
+        threaded: boolean (optiona)
+            Whether to launch the Server on a separate thread, allowing
+            interactive use.
 
         Returns
         -------
-        server: bokeh Server instance
+        server: bokeh.server.Server or threading.Thread
+            Returns the bokeh server instance or the thread the server
+            was launched on (if threaded=True)
         """
         def modify_doc(doc):
             return self.server_doc(doc)
         handler = FunctionHandler(modify_doc)
         app = Application(handler)
 
         from tornado.ioloop import IOLoop
-        loop = IOLoop.current()
-        if websocket_origin and not isinstance(websocket_origin, list):
-            websocket_origin = [websocket_origin]
-        opts = dict(allow_websocket_origin=websocket_origin) if websocket_origin else {}
-        opts['io_loop'] = loop
-        server = Server({'/': app}, port=port, **opts)
-        def show_callback():
-            server.show('/')
-        server.io_loop.add_callback(show_callback)
-        server.start()
+        if threaded:
+            from .util import StoppableThread
+            loop = IOLoop()
+            server = StoppableThread(target=self._start_server, io_loop=loop,
+                                     args=(app, loop, port, websocket_origin))
+            server.start()
+        else:
+            loop = IOLoop.current()
+            server = self._start_server(app, loop, port, websocket_origin)
 
         def sig_exit(*args, **kwargs):
             loop.add_callback_from_signal(do_stop)
@@ -369,10 +390,6 @@ def do_stop(*args, **kwargs):
             loop.stop()
 
         signal.signal(signal.SIGINT, sig_exit)
-        try:
-            loop.start()
-        except RuntimeError:
-            pass
         return server