Make sure that all process output makes it to the terminal

terminado/__init__.py

@@ -12,4 +12,4 @@
 # Prevent a warning about no attached handlers in Python 2
 logging.getLogger(__name__).addHandler(logging.NullHandler())
 
-__version__ = '0.8.3'
+__version__ = '0.8.4'

terminado/management.py

@@ -10,7 +10,7 @@
 if sys.version_info[0] < 3:
     byte_code = ord
 else:
-    byte_code = lambda x: x
+    def byte_code(x): return x
     unicode = str
 
 from collections import deque
@@ -31,18 +31,23 @@
 
 DEFAULT_TERM_TYPE = "xterm"
 
+
 class PtyWithClients(object):
-    def __init__(self, ptyproc):
-        self.ptyproc = ptyproc
+    def __init__(self, argv, env=[], cwd=None):
         self.clients = []
-        # Store the last few things read, so when a new client connects,
-        # it can show e.g. the most recent prompt, rather than absolutely
-        # nothing.
+        # If you start the process and then construct this object from it,
+        #  output generated by the process prior to the object's creation
+        #  is lost.  Hence the change from 0.8.3.
+        # Buffer output until a client connects; then let the client
+        #  drain the buffer.
+        # We keep the same read_buffer as before
         self.read_buffer = deque([], maxlen=10)
+        self.preopen_buffer = deque([])
+        self.ptyproc = PtyProcessUnicode.spawn(argv, env=env, cwd=cwd)
 
     def resize_to_smallest(self):
         """Set the terminal size to that of the smallest client dimensions.
-        
+
         A terminal not using the full space available is much nicer than a
         terminal trying to use more than the available space, so we keep it 
         sized to the smallest client.
@@ -57,7 +62,7 @@ def resize_to_smallest(self):
 
         if minrows == 10001 or mincols == 10001:
             return
-        
+
         rows, cols = self.ptyproc.getwinsize()
         if (rows, cols) != (minrows, mincols):
             self.ptyproc.setwinsize(minrows, mincols)
@@ -72,7 +77,7 @@ def killpg(self, sig=signal.SIGTERM):
             return self.ptyproc.kill(sig)
         pgid = os.getpgid(self.ptyproc.pid)
         os.killpg(pgid, sig)
-    
+
     @gen.coroutine
     def terminate(self, force=False):
         '''This forces a child process to terminate. It starts nicely with
@@ -86,7 +91,7 @@ def terminate(self, force=False):
                        signal.SIGTERM]
 
         loop = IOLoop.current()
-        sleep = lambda : gen.sleep(self.ptyproc.delayafterterminate)
+        def sleep(): return gen.sleep(self.ptyproc.delayafterterminate)
 
         if not self.ptyproc.isalive():
             raise gen.Return(True)
@@ -115,6 +120,7 @@ def terminate(self, force=False):
             else:
                 raise gen.Return(False)
 
+
 def _update_removing(target, changes):
     """Like dict.update(), but remove keys where the value is None.
     """
@@ -124,8 +130,10 @@ def _update_removing(target, changes):
         else:
             target[k] = v
 
+
 class TermManagerBase(object):
     """Base class for a terminal manager."""
+
     def __init__(self, shell_command, server_url="", term_settings={},
                  extra_env=None, ioloop=None):
         self.shell_command = shell_command
@@ -141,11 +149,11 @@ def __init__(self, shell_command, server_url="", term_settings={},
         else:
             import tornado.ioloop
             self.ioloop = tornado.ioloop.IOLoop.instance()
-        
+
     def make_term_env(self, height=25, width=80, winheight=0, winwidth=0, **kwargs):
         """Build the environment variables for the process in the terminal."""
         env = os.environ.copy()
-        env["TERM"] = self.term_settings.get("type",DEFAULT_TERM_TYPE)
+        env["TERM"] = self.term_settings.get("type", DEFAULT_TERM_TYPE)
         dimensions = "%dx%d" % (width, height)
         if winwidth and winheight:
             dimensions += ";%dx%d" % (winwidth, winheight)
@@ -168,8 +176,8 @@ def new_terminal(self, **kwargs):
         options.update(kwargs)
         argv = options['shell_command']
         env = self.make_term_env(**options)
-        pty = PtyProcessUnicode.spawn(argv, env=env, cwd=options.get('cwd', None))
-        return PtyWithClients(pty)
+        cwd = options.get('cwd', None)
+        return PtyWithClients(argv, env, cwd)
 
     def start_reading(self, ptywclients):
         """Connect a terminal to the tornado event loop to read data from it."""
@@ -194,7 +202,12 @@ def pty_read(self, fd, events=None):
         ptywclients = self.ptys_by_fd[fd]
         try:
             s = ptywclients.ptyproc.read(65536)
+            client_list = ptywclients.clients
             ptywclients.read_buffer.append(s)
+            if not client_list:
+                # No one to consume our output: buffer it.
+                ptywclients.preopen_buffer.append(s)
+                return
             for client in ptywclients.clients:
                 client.on_pty_read(s)
         except EOFError:
@@ -204,7 +217,7 @@ def pty_read(self, fd, events=None):
 
     def get_terminal(self, url_component=None):
         """Override in a subclass to give a terminal to a new websocket connection
-        
+
         The :class:`TermSocket` handler works with zero or one URL components
         (capturing groups in the URL spec regex). If it receives one, it is
         passed as the ``url_component`` parameter; otherwise, this is None.
@@ -232,6 +245,7 @@ def kill_all(self):
 
 class SingleTermManager(TermManagerBase):
     """All connections to the websocket share a common terminal."""
+
     def __init__(self, **kwargs):
         super(SingleTermManager, self).__init__(**kwargs)
         self.terminal = None
@@ -241,21 +255,24 @@ def get_terminal(self, url_component=None):
             self.terminal = self.new_terminal()
             self.start_reading(self.terminal)
         return self.terminal
-    
+
     @gen.coroutine
     def kill_all(self):
         yield super(SingleTermManager, self).kill_all()
         self.terminal = None
 
+
 class MaxTerminalsReached(Exception):
     def __init__(self, max_terminals):
         self.max_terminals = max_terminals
-    
+
     def __str__(self):
         return "Cannot create more than %d terminals" % self.max_terminals
 
+
 class UniqueTermManager(TermManagerBase):
     """Give each websocket a unique terminal to use."""
+
     def __init__(self, max_terminals=None, **kwargs):
         super(UniqueTermManager, self).__init__(**kwargs)
         self.max_terminals = max_terminals
@@ -284,17 +301,18 @@ def client_disconnected(self, websocket):
 class NamedTermManager(TermManagerBase):
     """Share terminals between websockets connected to the same endpoint.
     """
+
     def __init__(self, max_terminals=None, **kwargs):
         super(NamedTermManager, self).__init__(**kwargs)
         self.max_terminals = max_terminals
         self.terminals = {}
 
     def get_terminal(self, term_name):
         assert term_name is not None
-        
+
         if term_name in self.terminals:
             return self.terminals[term_name]
-        
+
         if self.max_terminals and len(self.terminals) >= self.max_terminals:
             raise MaxTerminalsReached(self.max_terminals)
 
@@ -331,13 +349,13 @@ def kill(self, name, sig=signal.SIGTERM):
     def terminate(self, name, force=False):
         term = self.terminals[name]
         yield term.terminate(force=force)
-    
+
     def on_eof(self, ptywclients):
         super(NamedTermManager, self).on_eof(ptywclients)
         name = ptywclients.term_name
         self.log.info("Terminal %s closed", name)
         self.terminals.pop(name, None)
-    
+
     @gen.coroutine
     def kill_all(self):
         yield super(NamedTermManager, self).kill_all()

terminado/websocket.py

@@ -18,13 +18,16 @@
 import tornado.web
 import tornado.websocket
 
+
 def _cast_unicode(s):
     if isinstance(s, bytes):
         return s.decode('utf-8')
     return s
 
+
 class TermSocket(tornado.websocket.WebSocketHandler):
     """Handler for a terminal websocket"""
+
     def initialize(self, term_manager):
         self.term_manager = term_manager
         self.term_name = ""
@@ -39,7 +42,7 @@ def origin_check(self, origin=None):
 
     def open(self, url_component=None):
         """Websocket connection opened.
-        
+
         Call our terminal manager to get a terminal, and connect to it as a
         client.
         """
@@ -52,12 +55,18 @@ def open(self, url_component=None):
         url_component = _cast_unicode(url_component)
         self.term_name = url_component or 'tty'
         self.terminal = self.term_manager.get_terminal(url_component)
-        for s in self.terminal.read_buffer:
-            self.on_pty_read(s)
         self.terminal.clients.append(self)
-
         self.send_json_message(["setup", {}])
         self._logger.info("TermSocket.open: Opened %s", self.term_name)
+        # Now drain the preopen buffer, if it exists.
+        buffered = ""
+        while True:
+            if not self.terminal.preopen_buffer:
+                break
+            s = self.terminal.preopen_buffer.popleft()
+            buffered += s
+        if buffered:
+            self.on_pty_read(buffered)
 
     def on_pty_read(self, text):
         """Data read from pty; send to frontend"""
@@ -69,13 +78,13 @@ def send_json_message(self, content):
 
     def on_message(self, message):
         """Handle incoming websocket message
-        
+
         We send JSON arrays, where the first element is a string indicating
         what kind of message this is. Data associated with the message follows.
         """
         ##logging.info("TermSocket.on_message: %s - (%s) %s", self.term_name, type(message), len(message) if isinstance(message, bytes) else message[:250])
         command = json.loads(message)
-        msg_type = command[0]    
+        msg_type = command[0]
 
         if msg_type == "stdin":
             self.terminal.ptyproc.write(command[1])
@@ -85,7 +94,7 @@ def on_message(self, message):
 
     def on_close(self):
         """Handle websocket closing.
-        
+
         Disconnect from our terminal, and tell the terminal manager we're
         disconnecting.
         """