feat: Notifications mailing system

devops/lms.yml

@@ -29,6 +29,25 @@ services:
       - ./rabbitmq.cookie:/var/lib/rabbitmq/.erlang.cookie
     networks:
       - lms
+
+  mailer:
+    image: lms:latest
+    command: celery -A lms.utils worker
+    volumes:
+      - ../lms/utils/:/app_dir/lms/utils/
+    environment:
+      - CELERY_RABBITMQ_ERLANG_COOKIE=AAVyo5djdSMGIZXiwEQs3JeVaBx5l14z
+      - CELERY_RABBITMQ_DEFAULT_USER=rabbit-user
+      - CELERY_RABBITMQ_DEFAULT_PASS=YgKlCvnYVzpTa3T9adG3NrMoUNe4Z5aZ
+      - CELERY_MAILER_VHOST=utils
+      - CELERY_RABBITMQ_HOST=rabbitmq
+      - CELERY_RABBITMQ_PORT=5672
+    links:
+      - rabbitmq
+    depends_on:
+      - rabbitmq
+    networks:
+      - lms
 
   checks-sandbox:
     image: lms:latest

lms/lmsdb/bootstrap.py

@@ -255,6 +255,18 @@ def _add_uuid_to_users_table(table: Model, _column: Field) -> None:
             user.save()
 
 
+def _add_mail_subscription_to_users_table(
+    table: Model, _column: Field,
+) -> None:
+    log.info(
+        'Adding mail subscription for users, might take some extra time...',
+    )
+    with db_config.database.transaction():
+        for user in table:
+            user.mail_subscription = True
+            user.save()
+
+
 def _api_keys_migration() -> bool:
     User = models.User
     _add_not_null_column(User, User.api_key, _add_api_keys_to_users_table)
@@ -309,6 +321,13 @@ def _uuid_migration() -> bool:
     return True
 
 
+def _mail_subscription() -> bool:
+    User = models.User
+    _add_not_null_column(
+        User, User.mail_subscription, _add_mail_subscription_to_users_table,
+    )
+
+
 def _assessment_migration() -> bool:
     Solution = models.Solution
     _add_not_null_column(Solution, Solution.assessment)
@@ -328,6 +347,7 @@ def main():
             _api_keys_migration()
             _last_course_viewed_migration()
             _uuid_migration()
+            _mail_subscription()
 
         if models.database.table_exists(models.UserCourse.__name__.lower()):
             _add_user_course_constaint()

lms/lmsdb/models.py

@@ -172,6 +172,7 @@ class User(UserMixin, BaseModel):
     api_key = CharField()
     last_course_viewed = ForeignKeyField(Course, null=True)
     uuid = UUIDField(default=uuid4, unique=True)
+    mail_subscription = BooleanField(default=True)
 
     def get_id(self):
         return str(self.uuid)
@@ -308,6 +309,9 @@ class Notification(BaseModel):
 
     def read(self) -> bool:
         self.viewed = True
+        mail = MailMessage.get_or_none(MailMessage.notification == self)
+        if mail:
+            mail.delete_instance()
         return bool(self.save())
 
     @classmethod
@@ -375,6 +379,28 @@ def on_notification_saved(
         instance.delete_instance()
 
 
+class MailMessage(BaseModel):
+    user = ForeignKeyField(User, backref='mails')
+    notification = ForeignKeyField(Notification, backref='mails')
+    date = DateTimeField(default=datetime.now)
+
+    @classmethod
+    def distincit_users(cls):
+        return cls.select(cls.user).distinct()
+
+    @classmethod
+    def by_user(cls, user: User) -> Iterable['MailMessage']:
+        return cls.select().where(cls.user == user)
+
+    @classmethod
+    def user_messages_number(cls, user: User) -> int:
+        return cls.select(fn.Count(cls.id)).where(cls.user == user).scalar()
+
+    @classmethod
+    def get_instances_number(cls):
+        return cls.select(fn.Count(cls.id))
+
+
 class Exercise(BaseModel):
     subject = CharField()
     date = DateTimeField()

lms/lmsweb/__init__.py

@@ -3,6 +3,7 @@
 import typing
 
 from flask import Flask
+from flask_apscheduler import APScheduler  # type: ignore
 from flask_babel import Babel  # type: ignore
 from flask_httpauth import HTTPBasicAuth
 from flask_limiter import Limiter  # type: ignore
@@ -48,6 +49,9 @@
 
 webmail = Mail(webapp)
 
+webscheduler = APScheduler(app=webapp)
+webscheduler.start()
+
 
 # Must import files after app's creation
 from lms.lmsdb import models  # NOQA: F401, E402, I202

lms/lmsweb/config.py.example

@@ -65,6 +65,10 @@ LOCALE = 'en'
 LIMITS_PER_MINUTE = 5
 LIMITS_PER_HOUR = 50
 
+# Scheduler
+SCHEDULER_API_ENABLED = True
+DEFAULT_DO_TASKS_EVERY_HOURS = 2
+
 # Change password settings
 MAX_INVALID_PASSWORD_TRIES = 5