jobctrl: use shell for subprocess if trying without it fails

IPython/Extensions/jobctrl.py

@@ -1,162 +1,174 b''
 """ Preliminary "job control" extensions for IPython 
 
 requires python 2.4 (or separate 'subprocess' module
 
 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,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]
     def __repr__(self):
         return '<IPython job "%s" PID=%d>' % (self.line, self.pid)
 
     def kill(self):
         kill_process(self.pid)
                   
 def startjob(job):
     p = IpyPopen(shlex.split(job), stdout=PIPE, shell = False)
     p.line = job
     return p
 
 def jobctrl_prefilter_f(self,line):    
     if line.startswith('&'):
         pre,fn,rest = self.split_user_input(line[1:])
         
         line = ip.IP.expand_aliases(fn,rest)
         return '_ip.startjob(%s)' % genutils.make_quoted_expr(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:
         dur = int(time.time()-t)
         print "%d: '%s' (%s) %d:%02d" % (pid,cmd,cwd, dur / 60,dur%60)
 
 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
 
+    jobentry = None
+    try:
+        try:
     p = Popen(cmd,shell = use_shell)
-    jobentry = 'tasks/t' + str(p.pid)
+        except WindowsError:
+            if use_shell:
+                # try with os.system
+                os.system(cmd)
+                return
+            else:
+                # have to go via shell, sucks
+                p = Popen(cmd,shell = True)
     
-    try:
+        jobentry = 'tasks/t' + str(p.pid)
         ip.db[jobentry] = (p.pid,cmd,os.getcwd(),time.time())
         p.communicate()
+
     finally:
+        if jobentry:
         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('shell_hook', jobctrl_shellcmd)
     ip.expose_magic('kill',magic_kill)
     ip.expose_magic('tasks',magic_tasks)
     
 install()