Allow jobs to be killed from the GUI

src/libprs500/gui2/dialogs/jobs.py

@@ -31,7 +31,17 @@ class JobsDialog(QDialog, Ui_JobsDialog):
         self.setWindowTitle(__appname__ + ' - Active Jobs')
         QObject.connect(self.jobs_view.model(), SIGNAL('modelReset()'), 
                         self.jobs_view.resizeColumnsToContents)
-        
+        QObject.connect(self.kill_button, SIGNAL('clicked()'),
+                        self.kill_job)
+        QObject.connect(self, SIGNAL('kill_job(int, PyQt_PyObject)'), 
+                        self.jobs_view.model().kill_job)
+    
+    def kill_job(self):
+        for index in self.jobs_view.selectedIndexes():
+            row = index.row()
+            self.emit(SIGNAL('kill_job(int, PyQt_PyObject)'), row, self)
+            return
+    
     def closeEvent(self, e):
         self.jobs_view.write_settings()
         e.accept()

src/libprs500/gui2/dialogs/jobs.ui

@@ -41,6 +41,13 @@
      </property>
     </widget>
    </item>
+   <item>
+    <widget class="QPushButton" name="kill_button" >
+     <property name="text" >
+      <string>&amp;Stop selected job</string>
+     </property>
+    </widget>
+   </item>
   </layout>
  </widget>
  <customwidgets>

src/libprs500/gui2/jobs.py

@@ -12,6 +12,7 @@
 ##    You should have received a copy of the GNU General Public License along
 ##    with this program; if not, write to the Free Software Foundation, Inc.,
 ##    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+from libprs500.gui2 import error_dialog
 import traceback, logging, collections
 
 from PyQt4.QtCore import QAbstractTableModel, QMutex, QObject, SIGNAL, Qt, \
@@ -170,7 +171,8 @@ class JobManager(QAbstractTableModel):
                 for job in [job for job in self.running_jobs if job.isFinished()]:
                     self.running_jobs.remove(job)
                     self.finished_jobs.appendleft(job)
-                    job.notify()
+                    if job.result != self.process_server.KILL_RESULT:
+                        job.notify()
                     self.emit(SIGNAL('job_done(int)'), job.id)
                     refresh = True
                 
@@ -317,7 +319,9 @@ class JobManager(QAbstractTableModel):
             if status == 0:
                 return self.running_icon
             if status == 2:
-                return self.done_icon if job.exception is None else self.error_icon
+                if job.exception or job.result == self.process_server.KILL_RESULT:
+                    return self.error_icon
+                return self.done_icon 
         return NONE
     
     def status_update(self, id, progress):
@@ -327,6 +331,22 @@ class JobManager(QAbstractTableModel):
                 index = self.index(i, 2)
                 self.emit(SIGNAL('dataChanged(QModelIndex, QModelIndex)'), index, index)
                 break
+            
+    def kill_job(self, row, gui_parent):
+        job, status = self.row_to_job(row)
+        if isinstance(job, DeviceJob):
+            error_dialog(gui_parent, _('Cannot kill job'), 
+                _('Cannot kill jobs that are communicating with the device as this may cause data corruption.')).exec_()
+            return
+        if status == 2:
+            error_dialog(gui_parent, _('Cannot kill job'), 
+                _('Cannot kill already completed jobs.')).exec_()
+            return
+        if status == 1:
+            error_dialog(gui_parent, _('Cannot kill job'), 
+                _('Cannot kill waiting jobs.')).exec_()
+            return
+        self.process_server.kill(job.id)
 
 class DetailView(QDialog, Ui_Dialog):
     

src/libprs500/parallel.py

@@ -20,7 +20,7 @@ from functools import partial
 from libprs500.ebooks.lrf.any.convert_from import main as any2lrf
 from libprs500.ebooks.lrf.web.convert_from import main as web2lrf
 from libprs500.gui2.lrf_renderer.main import main as lrfviewer
-from libprs500 import iswindows
+from libprs500 import iswindows, __appname__
 
 PARALLEL_FUNCS = {
                   'any2lrf'   : partial(any2lrf, gui_mode=True),
@@ -47,11 +47,44 @@ def cleanup(tdir):
 
 class Server(object):
     
+    #: Interval in seconds at which child processes are polled for status information
+    INTERVAL = 0.1
+    KILL_RESULT = 'Server: job killed by user|||#@#$%&*)*(*$#$%#$@&'
+    
     def __init__(self):
-        self.tdir = tempfile.mkdtemp('', 'libprs500_IPC_')
+        self.tdir = tempfile.mkdtemp('', '%s_IPC_'%__appname__)
         atexit.register(cleanup, self.tdir)
         self.stdout = {}
+        self.kill_jobs = []
         
+    def kill(self, job_id):
+        '''
+        Kill the job identified by job_id.
+        '''
+        self.kill_jobs.append(str(job_id))
+        
+    def _terminate(self, pid):
+        '''
+        Kill process identified by C{pid}.
+        @param pid: On unix a process number, on windows a process handle.
+        '''
+        if iswindows:
+            import win32api
+            try:
+                win32api.TerminateProcess(int(pid), -1)
+            except:
+                pass
+        else:
+            import signal
+            try:
+                try:
+                    os.kill(pid, signal.SIGTERM)
+                finally:
+                    time.sleep(2)
+                    os.kill(pid, signal.SIGKILL)                    
+            except:
+                pass
+    
     def run(self, job_id, func, args=[], kwdargs={}, monitor=True):
         '''
         Run a job in a separate process.
@@ -61,7 +94,8 @@ class Server(object):
         @param kwdargs: A dictionary of keyword arguments to pass to C{func}
         @param monitor: If False launch the child process and return. Do not monitor/communicate with it.
         @return: (result, exception, formatted_traceback, log) where log is the combined
-        stdout + stderr of the child process; or None if monitor is True.
+        stdout + stderr of the child process; or None if monitor is True. If a job is killed
+        by a call to L{kill()} then result will be L{KILL_RESULT}
         '''
         job_id = str(job_id)
         job_dir = os.path.join(self.tdir, job_id)
@@ -86,7 +120,9 @@ class Server(object):
             Popen((python, '-c', cmd))
             return 
         while p.returncode is None:
-            self.stdout[job_id].write(p.stdout.readline())
+            if job_id in self.kill_jobs:
+                self._terminate(p._handle if iswindows else p.pid)
+                return self.KILL_RESULT, None, None, _('Job killed by user') 
             p.poll()
             time.sleep(0.5) # Wait for half a second
         self.stdout[job_id].write(p.stdout.read())