added %tasks and %kill to jobctrl, as a powerful way to kill stalling foreground tasks (and ctrl+C won't cut it)

IPython/Extensions/jobctrl.py

@@ -2,31 +2,61 b''
 
 requires python 2.4 (or separate 'subprocess' module
 
-At the moment this is in a very "unhelpful" form, will be extended in the future.
-
-Usage:
-
-[ipython]|2> import jobctrl
-[ipython]|3> &ls
-         <3> <jobctrl.IpyPopen object at 0x00D87FD0>
-[ipython]|4> _3.go
------------> _3.go()
-ChangeLog
-IPython
-MANIFEST.in
-README
-README_Windows.txt
-
-...                     
+This provides 2 features, launching background jobs and killing foreground jobs from another IPython instance.
+
+Launching background jobs:
+
+    Usage:
+
+    [ipython]|2> import jobctrl
+    [ipython]|3> &ls
+             <3> <jobctrl.IpyPopen object at 0x00D87FD0>
+    [ipython]|4> _3.go
+    -----------> _3.go()
+    ChangeLog
+    IPython
+    MANIFEST.in
+    README
+    README_Windows.txt
+
+    ...
+
+Killing foreground tasks:
+
+Launch IPython instance, run a blocking command:
+
+    [Q:/ipython]|1> import jobctrl
+    [Q:/ipython]|2> cat
+
+Now launch a new IPython prompt and kill the process:
+
+    IPython 0.8.3.svn.r2919   [on Py 2.5]
+    [Q:/ipython]|1> import jobctrl
+    [Q:/ipython]|2> %tasks
+    6020: 'cat ' (Q:\ipython)
+    [Q:/ipython]|3> %kill
+    SUCCESS: The process with PID 6020 has been terminated.
+    [Q:/ipython]|4>
+
+(you don't need to specify PID for %kill if only one task is running)
 """                     
 
 from subprocess import Popen,PIPE
-import os,shlex
+import os,shlex,sys,time
 
 from IPython import genutils
 
 import IPython.ipapi
 
+if os.name == 'nt':
+    def kill_process(pid):
+        os.system('taskkill /F /PID %d' % pid)
+else:
+    def kill_process(pid):
+        os.system('kill -9 %d' % pid)
+    
+    
+
 class IpyPopen(Popen):
     def go(self):
         print self.communicate()[0]
@@ -34,8 +64,7 b' class IpyPopen(Popen):'
         return '<IPython job "%s" PID=%d>' % (self.line, self.pid)
 
     def kill(self):
-        assert os.name == 'nt' # xxx add posix version 
-        os.system('taskkill /PID %d' % self.pid)
+        kill_process(self.pid)
                   
 def startjob(job):
     p = IpyPopen(shlex.split(job), stdout=PIPE, shell = False)
@@ -51,11 +80,82 b' def jobctrl_prefilter_f(self,line):'
 
     raise IPython.ipapi.TryNext
 
+
+def job_list(ip):
+    keys = ip.db.keys('tasks/*')
+    ents = [ip.db[k] for k in keys]
+    return ents
+
+def magic_tasks(self,line):
+    """ Show a list of tasks.
+
+    A 'task' is a process that has been started in IPython when 'jobctrl' extension is enabled.
+    Tasks can be killed with %kill.
+    """
+    ip = self.getapi()
+    ents = job_list(ip)
+    if not ents:
+        print "No tasks running"
+    for pid,cmd,cwd,t in ents:
+        print "%d: '%s' (%s)" % (pid,cmd,cwd)
+
+def magic_kill(self,line):
+    """ Kill a task
+
+    Without args, either kill one task (if only one running) or show list (if many)
+    With arg, assume it's the process id.
+
+    %kill is typically (much) more powerful than trying to terminate a process with ctrl+C.
+    """
+    ip = self.getapi()
+    jobs  = job_list(ip)
+
+    if not line.strip():
+        if len(jobs) == 1:
+            kill_process(jobs[0][0])
+        else:
+            magic_tasks(self,line)
+        return
+        
+    try:
+        pid = int(line)
+        kill_process(pid)
+    except ValueError:
+        magic_tasks(self,line)
+        
+if sys.platform == 'win32':
+    shell_internal_commands = 'break chcp cls copy ctty date del erase dir md mkdir path prompt rd rmdir time 	type ver vol'.split()
+else:
+    # todo linux commands
+    shell_internal_commands = [] 
+
+
+def jobctrl_shellcmd(ip,cmd):
+    """ os.system replacement that stores process info to db['tasks/t1234'] """
+    cmdname = cmd.split(None,1)[0]
+    if cmdname in shell_internal_commands:
+        use_shell = True
+    else:
+        use_shell = False
+
+    p = Popen(cmd,shell = use_shell)
+    jobentry = 'tasks/t' + str(p.pid)
+    
+    try:
+        ip.db[jobentry] = (p.pid,cmd,os.getcwd(),time.time())
+        p.communicate()
+    finally:
+        del ip.db[jobentry]
+
+
 def install():
     global ip
     ip = IPython.ipapi.get()
     # needed to make startjob visible as _ip.startjob('blah')
     ip.startjob = startjob
-    ip.set_hook('input_prefilter', jobctrl_prefilter_f)     
+    ip.set_hook('input_prefilter', jobctrl_prefilter_f)
+    ip.set_hook('shell_hook', jobctrl_shellcmd)
+    ip.expose_magic('kill',magic_kill)
+    ip.expose_magic('tasks',magic_tasks)
     
-install()
  No newline at end of file
+install()