Add the wallabag tag consumer.

Signed-off-by: Jan Losinski <losinski@wh2.tu-dresden.de>

consumer.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+import asyncio
+
+from logbook import Logger
+from sqlalchemy.orm import joinedload
+
+from models import User, Job
+
+logger = Logger(__name__)
+
+
+class Consumer:
+    def __init__(self, wallabag, session, sender, interval=30):
+        self.wallabag = wallabag
+        self.session = session
+        self.interval = interval
+        self.sender = sender
+        self.running = True
+
+    async def fetch_jobs(self, user):
+        logger.info("Fetch entries for user {}", user.name)
+        async for entry in self.wallabag.fetch_entries(user):
+            logger.info("Schedule job to send entry {}", entry.id)
+            job = Job(article=entry.id, title=entry.title, format=entry.tag.format)
+            user.jobs.append(job)
+            await self.wallabag.remove_tag(user, entry)
+
+    async def process_job(self, job):
+        logger.info("Process export for job {id} ({format})", id=job.article, format=job.format)
+        data = await self.wallabag.export_article(job.user, job.article, job.format)
+        await self.sender.send_mail(job, data)
+        self.session.delete(job)
+
+    async def consume(self):
+        while self.running:
+            logger.info("Start consume run")
+            fetches = [self.fetch_jobs(user) for user in self.session.query(User).all()]
+            await asyncio.gather(*fetches)
+            self.session.commit()
+
+            jobs = [self.process_job(job) for job in self.session.query(Job).options(joinedload('user'))]
+            await asyncio.gather(*jobs)
+            self.session.commit()
+
+            asyncio.sleep(self.interval)
+