split base_launch_kernel into make_kernel_cmd / launch_kernel

IPython/zmq/entry_point.py

@@ -1,226 +1,262 b''
 """ Defines helper functions for creating kernel entry points and process
 launchers.
 """
 
-# Standard library imports.
-import atexit
+# Standard library imports
 import json
 import os
 import socket
 from subprocess import Popen, PIPE
 import sys
 import tempfile
 
 # System library imports
 
 # IPython imports
 from IPython.utils.localinterfaces import LOCALHOST
 from IPython.utils.py3compat import bytes_to_str
 
-# Local imports.
+# Local imports
 from parentpoller import ParentPollerWindows
 
 def write_connection_file(fname=None, shell_port=0, iopub_port=0, stdin_port=0, hb_port=0,
                          ip=LOCALHOST, key=b'', transport='tcp'):
     """Generates a JSON config file, including the selection of random ports.
     
     Parameters
     ----------
 
     fname : unicode
         The path to the file to write
 
     shell_port : int, optional
         The port to use for ROUTER channel.
 
     iopub_port : int, optional
         The port to use for the SUB channel.
 
     stdin_port : int, optional
         The port to use for the REQ (raw input) channel.
 
     hb_port : int, optional
         The port to use for the hearbeat REP channel.
 
     ip  : str, optional
         The ip address the kernel will bind to.
 
     key : str, optional
         The Session key used for HMAC authentication.
 
     """
     # default to temporary connector file
     if not fname:
         fname = tempfile.mktemp('.json')
     
     # Find open ports as necessary.
     
     ports = []
     ports_needed = int(shell_port <= 0) + int(iopub_port <= 0) + \
                    int(stdin_port <= 0) + int(hb_port <= 0)
     if transport == 'tcp':
         for i in range(ports_needed):
             sock = socket.socket()
             sock.bind(('', 0))
             ports.append(sock)
         for i, sock in enumerate(ports):
             port = sock.getsockname()[1]
             sock.close()
             ports[i] = port
     else:
         N = 1
         for i in range(ports_needed):
             while os.path.exists("%s-%s" % (ip, str(N))):
                 N += 1
             ports.append(N)
             N += 1
     if shell_port <= 0:
         shell_port = ports.pop(0)
     if iopub_port <= 0:
         iopub_port = ports.pop(0)
     if stdin_port <= 0:
         stdin_port = ports.pop(0)
     if hb_port <= 0:
         hb_port = ports.pop(0)
     
     cfg = dict( shell_port=shell_port,
                 iopub_port=iopub_port,
                 stdin_port=stdin_port,
                 hb_port=hb_port,
               )
     cfg['ip'] = ip
     cfg['key'] = bytes_to_str(key)
     cfg['transport'] = transport
     
     with open(fname, 'w') as f:
         f.write(json.dumps(cfg, indent=2))
     
     return fname, cfg
     
 
-def base_launch_kernel(code, fname, stdin=None, stdout=None, stderr=None,
-                        executable=None, independent=False, extra_arguments=[],
-                        cwd=None):
+def make_kernel_cmd(code, executable=None, extra_arguments=[], **kw):
     """ Launches a localhost kernel, binding to the specified ports.
 
     Parameters
     ----------
     code : str,
         A string of Python code that imports and executes a kernel entry point.
 
-    stdin, stdout, stderr : optional (default None)
-        Standards streams, as defined in subprocess.Popen.
+    executable : str, optional (default sys.executable)
+        The Python executable to use for the kernel process.
+
+    extra_arguments : list, optional
+        A list of extra arguments to pass when executing the launch code.
+    
+    Returns
+    -------
+    
+    A Popen command list
+    """
+    
+    # Build the kernel launch command.
+    if executable is None:
+        executable = sys.executable
+    arguments = [ executable, '-c', code, '-f', '{connection_file}' ]
+    arguments.extend(extra_arguments)
 
-    fname : unicode, optional
-        The JSON connector file, containing ip/port/hmac key information.
+    # Spawn a kernel.
+    if sys.platform == 'win32':
 
-    key : str, optional
-        The Session key used for HMAC authentication.
+        # If the kernel is running on pythonw and stdout/stderr are not been
+        # re-directed, it will crash when more than 4KB of data is written to
+        # stdout or stderr. This is a bug that has been with Python for a very
+        # long time; see http://bugs.python.org/issue706263.
+        # A cleaner solution to this problem would be to pass os.devnull to
+        # Popen directly. Unfortunately, that does not work.
+        if executable.endswith('pythonw.exe'):
+            arguments.append('--no-stdout')
+            arguments.append('--no-stderr')
 
-    executable : str, optional (default sys.executable)
-        The Python executable to use for the kernel process.
+    return arguments
+
+
+def launch_kernel(cmd, stdin=None, stdout=None, stderr=None,
+                        independent=False,
+                        cwd=None, ipython_kernel=True,
+                        **kw
+                        ):
+    """ Launches a localhost kernel, binding to the specified ports.
+
+    Parameters
+    ----------
+    cmd : Popen list,
+        A string of Python code that imports and executes a kernel entry point.
+
+    stdin, stdout, stderr : optional (default None)
+        Standards streams, as defined in subprocess.Popen.
 
     independent : bool, optional (default False)
         If set, the kernel process is guaranteed to survive if this process
         dies. If not set, an effort is made to ensure that the kernel is killed
         when this process dies. Note that in this case it is still good practice
         to kill kernels manually before exiting.
 
-    extra_arguments : list, optional
-        A list of extra arguments to pass when executing the launch code.
-    
     cwd : path, optional
         The working dir of the kernel process (default: cwd of this process).
 
+    ipython_kernel : bool, optional
+        Whether the kernel is an official IPython one,
+        and should get a bit of special treatment.
+
     Returns
     -------
-    A tuple of form:
-        (kernel_process, shell_port, iopub_port, stdin_port, hb_port)
-    where kernel_process is a Popen object and the ports are integers.
-    """
     
-    # Build the kernel launch command.
-    if executable is None:
-        executable = sys.executable
-    arguments = [ executable, '-c', code, '-f', fname ]
-    arguments.extend(extra_arguments)
+    Popen instance for the kernel subprocess
+    """
 
     # Popen will fail (sometimes with a deadlock) if stdin, stdout, and stderr
     # are invalid. Unfortunately, there is in general no way to detect whether
     # they are valid.  The following two blocks redirect them to (temporary)
     # pipes in certain important cases.
 
     # If this process has been backgrounded, our stdin is invalid. Since there
     # is no compelling reason for the kernel to inherit our stdin anyway, we'll
     # place this one safe and always redirect.
     redirect_in = True
     _stdin = PIPE if stdin is None else stdin
 
     # If this process in running on pythonw, we know that stdin, stdout, and
     # stderr are all invalid.
     redirect_out = sys.executable.endswith('pythonw.exe')
     if redirect_out:
         _stdout = PIPE if stdout is None else stdout
         _stderr = PIPE if stderr is None else stderr
     else:
         _stdout, _stderr = stdout, stderr
 
     # Spawn a kernel.
     if sys.platform == 'win32':
+        
         # Create a Win32 event for interrupting the kernel.
         interrupt_event = ParentPollerWindows.create_interrupt_event()
-        arguments += [ '--interrupt=%i'%interrupt_event ]
-
-        # If the kernel is running on pythonw and stdout/stderr are not been
-        # re-directed, it will crash when more than 4KB of data is written to
-        # stdout or stderr. This is a bug that has been with Python for a very
-        # long time; see http://bugs.python.org/issue706263.
-        # A cleaner solution to this problem would be to pass os.devnull to
-        # Popen directly. Unfortunately, that does not work.
-        if executable.endswith('pythonw.exe'):
-            if stdout is None:
-                arguments.append('--no-stdout')
-            if stderr is None:
-                arguments.append('--no-stderr')
+        if ipython_kernel:
+            cmd += [ '--interrupt=%i' % interrupt_event ]
+
+            # If the kernel is running on pythonw and stdout/stderr are not been
+            # re-directed, it will crash when more than 4KB of data is written to
+            # stdout or stderr. This is a bug that has been with Python for a very
+            # long time; see http://bugs.python.org/issue706263.
+            # A cleaner solution to this problem would be to pass os.devnull to
+            # Popen directly. Unfortunately, that does not work.
+            if cmd[0].endswith('pythonw.exe'):
+                if stdout is None:
+                    cmd.append('--no-stdout')
+                if stderr is None:
+                    cmd.append('--no-stderr')
 
         # Launch the kernel process.
         if independent:
-            proc = Popen(arguments,
+            proc = Popen(cmd,
                          creationflags=512, # CREATE_NEW_PROCESS_GROUP
                          stdin=_stdin, stdout=_stdout, stderr=_stderr)
         else:
-            try:
-                from _winapi import DuplicateHandle, GetCurrentProcess, \
-                    DUPLICATE_SAME_ACCESS
-            except:
-                from _subprocess import DuplicateHandle, GetCurrentProcess, \
-                    DUPLICATE_SAME_ACCESS
-            pid = GetCurrentProcess()
-            handle = DuplicateHandle(pid, pid, pid, 0,
-                                     True, # Inheritable by new processes.
-                                     DUPLICATE_SAME_ACCESS)
-            proc = Popen(arguments + ['--parent=%i'%int(handle)],
-                         stdin=_stdin, stdout=_stdout, stderr=_stderr)
+            if ipython_kernel:
+                try:
+                    from _winapi import DuplicateHandle, GetCurrentProcess, \
+                        DUPLICATE_SAME_ACCESS
+                except:
+                    from _subprocess import DuplicateHandle, GetCurrentProcess, \
+                        DUPLICATE_SAME_ACCESS
+                pid = GetCurrentProcess()
+                handle = DuplicateHandle(pid, pid, pid, 0,
+                                         True, # Inheritable by new processes.
+                                         DUPLICATE_SAME_ACCESS)
+                cmd +=[ '--parent=%i' % handle ]
+            
+            
+            proc = Popen(cmd,
+                         stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd)
 
         # Attach the interrupt event to the Popen objet so it can be used later.
         proc.win32_interrupt_event = interrupt_event
 
     else:
         if independent:
-            proc = Popen(arguments, preexec_fn=lambda: os.setsid(),
+            proc = Popen(cmd, preexec_fn=lambda: os.setsid(),
                          stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd)
         else:
-            proc = Popen(arguments + ['--parent=1'],
+            if ipython_kernel:
+                cmd += ['--parent=1']
+            proc = Popen(cmd,
                          stdin=_stdin, stdout=_stdout, stderr=_stderr, cwd=cwd)
 
     # Clean up pipes created to work around Popen bug.
     if redirect_in:
         if stdin is None:
             proc.stdin.close()
     if redirect_out:
         if stdout is None:
             proc.stdout.close()
         if stderr is None:
             proc.stderr.close()
 
     return proc