prepare to merge with pyquarantine project

pyquarantine/mailer.py

@@ -0,0 +1,86 @@
+# pyquarantine is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# pyquarantine is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with pyquarantine.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import logging
+import smtplib
+
+from multiprocessing import Process, Queue
+
+
+logger = logging.getLogger(__name__)
+queue = Queue(maxsize=50)
+process = None
+
+
+def smtp_send(smtp_host, smtp_port, mailfrom, recipient, mail):
+    s = smtplib.SMTP(host=smtp_host, port=smtp_port)
+    s.ehlo()
+    if s.has_extn("STARTTLS"):
+        s.starttls()
+        s.ehlo()
+    s.sendmail(mailfrom, [recipient], mail)
+    s.quit()
+
+
+def mailprocess():
+    "Mailer process to send emails asynchronously."
+    global logger
+    global queue
+
+    try:
+        while True:
+            m = queue.get()
+            if not m:
+                break
+
+            smtp_host, smtp_port, qid, mailfrom, recipient, mail, emailtype = m
+            try:
+                smtp_send(smtp_host, smtp_port, mailfrom, recipient, mail)
+            except Exception as e:
+                logger.error(
+                    f"{qid}: error while sending {emailtype} "
+                    f"to '{recipient}': {e}")
+            else:
+                logger.info(
+                    f"{qid}: successfully sent {emailtype} to: {recipient}")
+    except KeyboardInterrupt:
+        pass
+    logger.debug("mailer process terminated")
+
+
+def sendmail(smtp_host, smtp_port, qid, mailfrom, recipients, mail,
+             emailtype="email"):
+    "Send an email."
+    global logger
+    global process
+    global queue
+
+    if isinstance(recipients, str):
+        recipients = [recipients]
+
+    # start mailprocess if it is not started yet
+    if process is None:
+        process = Process(target=mailprocess)
+        process.daemon = True
+        logger.debug("starting mailer process")
+        process.start()
+
+    for recipient in recipients:
+        try:
+            queue.put(
+                (smtp_host, smtp_port, qid, mailfrom, recipient, mail,
+                 emailtype),
+                timeout=30)
+        except Queue.Full:
+            raise RuntimeError("email queue is full")