Add small util for killing hanging processes.

tools/task_kill.py

+#!/usr/bin/env python
+#
+# Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+# for details. All rights reserved. Use of this source code is governed by a
+# BSD-style license that can be found in the LICENSE file.
+#
+
+# A script to kill hanging processs. The tool will return non-zero if any
+# process was actually found.
+#
+
+import optparse
+import os
+import signal
+import shutil
+import string
+import subprocess
+import sys
+import utils
+
+os_name = None
+
+POSIX_LIST = 'ps -e -o comm,pid'

[kustermann, 2013/08/27 08:42:22]

Please add a comment, which gives an example output. Same for windows.

[ricow1, 2013/08/27 11:45:25]

This has been moved into the platform specific functions, with sample output

+POSIX_INFO = 'ps -p %s -o args'
+
+LIST_COMMAND = {
+  'win32': 'wmic process get Caption,Processid',
+  'macos': POSIX_LIST,
+  'linux': POSIX_LIST,
+}
+
+INFO_COMMAND = {
+  'win32': 'wmic process where Processid=%s get CommandLine',
+  'macos': POSIX_INFO,
+  'linux': POSIX_INFO,
+}
+
+def GetOptions():
+  parser = optparse.OptionParser("usage: %prog [options]")
+  parser.add_option("--kill_dart", default=True,
+                    help="Kill all dart processes")
+  parser.add_option("--kill_browsers", default=False,

[kustermann, 2013/08/27 08:42:22]

Why the difference in default values?

[ricow1, 2013/08/27 11:45:25]

Because if people use it locally I don't want to kill their browsers by default

+                     help="Kill all browser processes")
+  (options, args) = parser.parse_args()
+  return options
+
+def GetPids(process_name):
+  # We asume that the list command will return lines in the format:
+  # PROCESS_NAME WHITESPACE* PID

[kustermann, 2013/08/27 08:42:22]

Don't know if this is working. Often on mac and windows we've spaces in
directory/executable names.

I'd prefer a regexp like this:
line = re.compile('^(.+)\s+([0-9]+)$')

It's better for documentation and probably more reliable.

[ricow1, 2013/08/27 11:45:25]

I changed the order now and just return the last part of the string on posix, on
windows we actually get it for the explicit binary name

+  p = subprocess.Popen(LIST_COMMAND[os_name],
+                       stdout=subprocess.PIPE,
+                       stderr=subprocess.PIPE,
+                       shell=True)
+  output, stderr = p.communicate()
+  results = []
+
+  lines = output.splitlines()
+  # Pop the header
+  lines.pop(0)

[kustermann, 2013/08/27 08:42:22]

Do we have this header on windows and linux?

[ricow1, 2013/08/27 11:45:25]

Yes we did, but not with the new command 

+  for line in lines:
+    split = line.split()
+    if len(split) == 2 and split[0] == process_name:
+      results.append(split[1])

[kustermann, 2013/08/27 08:42:22]

see comment above.

[ricow1, 2013/08/27 11:45:25]

Done.

+  return results
+
+def PrintPidInfo(pid):
+  # We asume that the list command will return lines in the format:
+  # EXECUTABLE_PATH ARGS
+  # There may be blank strings in the output
+  p = subprocess.Popen(INFO_COMMAND[os_name] % pid,
+                       stdout=subprocess.PIPE,
+                       stderr=subprocess.PIPE,
+                       shell=True)
+  output, stderr = p.communicate()
+  lines = output.splitlines()
+
+  # Pop the header
+  lines.pop(0)
+  for line in lines:
+    # wmic will output a bunch of empty strings, we ignore these
+    if len(line) >= 1:
+      print("Hanging process info:")
+      print("  PID: %s" % pid)
+      print("  Command line: %s" % line)

[kustermann, 2013/08/27 08:42:22]

Same comments as above.

[ricow1, 2013/08/27 11:45:25]

Done.

+
+def KillPosix(pid):
+  try:
+    os.kill(int(pid), signal.SIGTERM);

[kustermann, 2013/08/27 08:42:22]

What if SIGTERM is ignored? We should really make sure, that the hanging
processes are gone.

[ricow1, 2013/08/27 11:45:25]

Done.

[ricow1, 2013/08/27 11:45:25]

Done.

+  except:
+    # Ignore this, the process is already dead from killing another process.
+    pass
+
+def KillWindows(pid):
+  # os.kill is not available until python 2.7
+  cmd = "taskkill /F /PID %s" % pid
+  p = subprocess.Popen(cmd,
+                       stdout=subprocess.PIPE,
+                       stderr=subprocess.PIPE,
+                       shell=True)
+
+def GetExecutableName(name):
+  if (os_name == "win32"):
+    return "%s.exe" % name
+  else:
+    return name
+
+def Kill(name):
+  print("***************** Killing %s *****************" % name)
+  pids = GetPids(GetExecutableName(name))
+  for pid in pids:
+    PrintPidInfo(pid);
+    if (os_name == "win32"):
+      KillWindows(pid)
+    else:
+      KillPosix(pid)
+    print("Killed pid: %s" % pid)

[kustermann, 2013/08/27 08:42:22]

You don't know if it was successfull or not at this place (maybe we actually
didn't kill it)

+  if (len(pids) == 0):
+    print("  Nothing to kill")

[kustermann, 2013/08/27 08:42:22]

We could print this out multiple times (for every Kill() invocation) -- which is
strange.

[ricow1, 2013/08/27 11:45:25]

That is what I want, the log will explicitly show that we try to kill the
process

+  return len(pids)

[kustermann, 2013/08/27 08:42:22]

We should return here how many we actually killed.

[ricow1, 2013/08/27 11:45:25]

well, that is hard to figure out without listing again, kill the main chrome
process for example will take down the render processes as well

+
+def KillBrowsers():
+  status = Kill('firefox')
+  status += Kill('chrome')
+  status += Kill('iexplore')

[kustermann, 2013/08/27 08:42:22]

"status" is not the correct name. We should call it 'num_killed' or something
like that. 

[ricow1, 2013/08/27 11:45:25]

Well, it is the return status :-)

+  status += Kill('Safari')

[kustermann, 2013/08/27 08:42:22]

firefox is probably uppercase on mac. We should make these names os dependend.
(Then the GetExecutableName() function is also obsolete)

[ricow1, 2013/08/27 11:45:25]

No it is not, but chrome is

+  return status
+
+def KillDart():
+  status = Kill("dart")
+  return status
+
+def Main():
+  global os_name
+  options = GetOptions()
+  os_name = utils.GuessOS()

[kustermann, 2013/08/27 08:42:22]

Don't do it here. Just do assign it at the module scope.

[ricow1, 2013/08/27 11:45:25]

Done.

+  status = 0
+  if (options.kill_dart):
+    status += KillDart();
+  if (options.kill_browsers):
+    status += status + KillBrowsers()
+  return status
+
+if __name__ == '__main__':
+  sys.exit(Main())