Fix microsoft#200: Local attach

Add --pid option to ptvsd command line. When used, injects the debugger
into the process with the specified ID, such that it connects back to
the specified host/port.

ptvsd/__main__.py

@@ -6,6 +6,7 @@
 import os.path
 import sys
 
+from ptvsd._attach import attach_main
 from ptvsd._local import debug_main, run_main
 from ptvsd.socket import Address
 from ptvsd.version import __version__, __author__  # noqa
@@ -46,6 +47,7 @@
 USAGE = """
   {0} [-h] [-V] [--nodebug] [--host HOST | --server-host HOST] --port PORT -m MODULE [arg ...]
   {0} [-h] [-V] [--nodebug] [--host HOST | --server-host HOST] --port PORT FILENAME [arg ...]
+  {0} [-h] [-V] --host HOST --port PORT --pid PROCESS_ID
 """  # noqa
 
 
@@ -129,8 +131,8 @@ def _group_args(argv):
             supported.append(arg)
 
         # ptvsd support
-        elif arg in ('--host', '--server-host', '--port', '-m'):
-            if arg == '-m':
+        elif arg in ('--host', '--server-host', '--port', '--pid', '-m'):
+            if arg == '-m' or arg == '--pid':
                 gottarget = True
             supported.append(arg)
             if nextarg is not None:
@@ -155,14 +157,17 @@ def _parse_args(prog, argv):
         prog=prog,
         usage=USAGE.format(prog),
     )
+
     parser.add_argument('--nodebug', action='store_true')
+
     host = parser.add_mutually_exclusive_group()
     host.add_argument('--host')
     host.add_argument('--server-host')
     parser.add_argument('--port', type=int, required=True)
 
     target = parser.add_mutually_exclusive_group(required=True)
     target.add_argument('-m', dest='module')
+    target.add_argument('--pid', type=int)
     target.add_argument('filename', nargs='?')
 
     parser.add_argument('--single-session', action='store_true')
@@ -186,28 +191,36 @@ def _parse_args(prog, argv):
     else:
         args.address = Address.as_client(clienthost, ns.pop('port'))
 
+    pid = ns.pop('pid')
     module = ns.pop('module')
     filename = ns.pop('filename')
-    if module is None:
-        args.name = filename
-        args.kind = 'script'
-    else:
+    if pid is not None:
+        args.name = pid
+        args.kind = 'pid'
+    elif module is not None:
         args.name = module
         args.kind = 'module'
-    #if argv[-1] != args.name or (module and argv[-1] != '-m'):
-    #    parser.error('script/module must be last arg')
+    else:
+        args.name = filename
+        args.kind = 'script'
 
     return args
 
 
-def main(addr, name, kind, extra=(), nodebug=False, **kwargs):
-    if nodebug:
+def handle_args(addr, name, kind, extra=(), nodebug=False, **kwargs):
+    if kind == 'pid':
+        attach_main(addr, name, *extra, **kwargs)
+    elif nodebug:
         run_main(addr, name, kind, *extra, **kwargs)
     else:
         debug_main(addr, name, kind, *extra, **kwargs)
 
 
-if __name__ == '__main__':
-    args, extra = parse_args()
-    main(args.address, args.name, args.kind, extra, nodebug=args.nodebug,
+def main(argv=None):
+    args, extra = parse_args(argv)
+    handle_args(args.address, args.name, args.kind, extra, nodebug=args.nodebug,
          singlesession=args.single_session, wait=args.wait)
+
+
+if __name__ == '__main__' or __name__ == 'ptvsd.__main__':
+    main()

ptvsd/_attach.py

@@ -0,0 +1,39 @@
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See LICENSE in the project root
+# for license information.
+
+import os.path
+import sys
+
+import ptvsd
+import pydevd
+
+def attach_main(address, pid, *extra, **kwargs):
+    hostname, port_num = address
+
+    ptvsd_path = os.path.join(ptvsd.__file__, '../..')
+    pydevd_attach_to_process_path = os.path.join(os.path.dirname(pydevd.__file__), 'pydevd_attach_to_process')
+    sys.path.append(pydevd_attach_to_process_path)
+    from add_code_to_python_process import run_python_code
+
+    # The code must not contain single quotes. Also, it might be running on a different
+    # Python version once it's injected. Encoding string literals as raw UTF-8 byte
+    # values takes care of both.
+    code = '''
+ptvsd_path = bytearray({ptvsd_path}).decode("utf-8")
+hostname = bytearray({hostname}).decode("utf-8")
+
+import sys
+sys.path.insert(0, ptvsd_path)
+import ptvsd
+del sys.path[0]
+
+from ptvsd._remote import attach
+attach((hostname, {port_num}))
+'''
+
+    code = code.format(
+        ptvsd_path=repr(list(ptvsd_path.encode('utf-8'))),
+        hostname=repr(list(hostname.encode('utf-8'))),
+        port_num=port_num)
+    run_python_code(pid, code, connect_debugger_tracing=True)

ptvsd/_remote.py

@@ -83,3 +83,21 @@ def start_daemon():
                      stderrToServer=redirect_output,
                      port=port,
                      suspend=False)
+
+
+def attach(address,
+           redirect_output=True,
+           _pydevd=pydevd,
+           _install=install,
+           **kwargs):
+
+    host, port = address
+    daemon = _install(_pydevd,
+                      address,
+                      singlesession=False,
+                      **kwargs)
+    _pydevd.settrace(host=host,
+                     port=port,
+                     stdoutToServer=redirect_output,
+                     stderrToServer=redirect_output,
+                     suspend=False)

ptvsd/attach_server.py

@@ -3,7 +3,9 @@
 # for license information.
 
 from ptvsd._remote import (
-    enable_attach as ptvsd_enable_attach, _pydevd_settrace,
+    attach as ptvsd_attach,
+    enable_attach as ptvsd_enable_attach,
+    _pydevd_settrace,
 )
 from ptvsd.wrapper import debugger_attached
 
@@ -71,6 +73,31 @@ def enable_attach(address=(DEFAULT_HOST, DEFAULT_PORT), redirect_output=True):
     )
 
 
+def attach(address, redirect_output=True):
+    """Attaches this process to the debugger listening on a given address.
+
+    Parameters
+    ----------
+    address : (str, int), optional
+        Specifies the interface and port on which the debugger is listening
+        for TCP connections. It is in the same format as used for
+        regular sockets of the `socket.AF_INET` family, i.e. a tuple of
+        ``(hostname, port)``.
+    redirect_output : bool, optional
+        Specifies whether any output (on both `stdout` and `stderr`) produced
+        by this program should be sent to the debugger. Default is ``True``.
+    """
+    if is_attached():
+        return
+    debugger_attached.clear()
+
+    # Ensure port is int
+    port = address[1]
+    address = (address[0], port if type(port) is int else int(port))
+
+    ptvsd_attach(address, redirect_output=redirect_output)
+
+
 # TODO: Add disable_attach()?