Email sending: Allow user to stop email jobs (note that stopping may not actually prevent the email from being sent, depending on when the stop happens). Also automatically abort email sending if it takes longer than 15mins. Fixes #795960 (E-mail task hangs)

src/calibre/gui2/email.py

@@ -9,6 +9,7 @@ __docformat__ = 'restructuredtext en'
 import os, socket, time
 from binascii import unhexlify
 from functools import partial
+from threading import Thread
 from itertools import repeat
 
 from calibre.utils.smtp import (compose_mail, sendmail, extract_email_address,
@@ -22,9 +23,30 @@ from calibre.library.save_to_disk import get_components
 from calibre.utils.config import tweaks
 from calibre.gui2.threaded_jobs import ThreadedJob
 
+class Worker(Thread):
+
+    def __init__(self, func, args):
+        Thread.__init__(self)
+        self.daemon = True
+        self.exception = self.tb = None
+        self.func, self.args = func, args
+
+    def run(self):
+        #time.sleep(1000)
+        try:
+            self.func(*self.args)
+        except Exception as e:
+            import traceback
+            self.exception = e
+            self.tb = traceback.format_exc()
+        finally:
+            self.func = self.args = None
+
+
 class Sendmail(object):
 
     MAX_RETRIES = 1
+    TIMEOUT = 15 * 60 # seconds
 
     def __init__(self):
         self.calculate_rate_limit()
@@ -42,22 +64,32 @@ class Sendmail(object):
             abort=None, notifications=None):
 
         try_count = 0
-        while try_count <= self.MAX_RETRIES:
+        while True:
             if try_count > 0:
                 log('\nRetrying in %d seconds...\n' %
                         self.rate_limit)
-            try:
-                self.sendmail(attachment, aname, to, subject, text, log)
-                try_count = self.MAX_RETRIES
-                log('Email successfully sent')
-            except:
+            worker = Worker(self.sendmail,
+                    (attachment, aname, to, subject, text, log))
+            worker.start()
+            start_time = time.time()
+            while worker.is_alive():
+                worker.join(0.2)
                 if abort.is_set():
+                    log('Sending aborted by user')
                     return
-                if try_count == self.MAX_RETRIES:
-                    raise
-                log.exception('\nSending failed...\n')
-
+                if time.time() - start_time > self.TIMEOUT:
+                    log('Sending timed out')
+                    raise Exception(
+                            'Sending email %r to %r timed out, aborting'% (subject,
+                                to))
+            if worker.exception is None:
+                log('Email successfully sent')
+                return
+            log.error('\nSending failed...\n')
+            log.debug(worker.tb)
             try_count += 1
+            if try_count > self.MAX_RETRIES:
+                raise worker.exception
 
     def sendmail(self, attachment, aname, to, subject, text, log):
         while time.time() - self.last_send_time <= self.rate_limit:
@@ -90,7 +122,7 @@ def send_mails(jobnames, callback, attachments, to_s, subjects,
             attachments, to_s, subjects, texts, attachment_names):
         description = _('Email %s to %s') % (name, to)
         job = ThreadedJob('email', description, gui_sendmail, (attachment, aname, to,
-                subject, text), {}, callback, killable=False)
+                subject, text), {}, callback)
         job_manager.run_threaded_job(job)