Add email notification

cynomys/migrations/0001_initial.py

-# Generated by Django 3.2.4 on 2021-06-24 13:13
+# Generated by Django 3.2.4 on 2021-06-25 08:38
 
 from django.db import migrations, models
 import django.db.models.deletion
@@ -9,17 +9,18 @@ class Migration(migrations.Migration):
     initial = True
 
     dependencies = [
-        ('django_celery_beat', '0016_auto_20210624_1313'),
+        ('django_celery_beat', '0016_auto_20210625_0828'),
     ]
 
     operations = [
         migrations.CreateModel(
-            name='Deltas',
+            name='Delta',
             fields=[
                 ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
-                ('timestamp', models.DateTimeField(auto_now=True)),
+                ('timestamp', models.DateTimeField(editable=False)),
                 ('success', models.BooleanField(blank=True, null=True)),
-                ('latest_check', models.DateTimeField(auto_now=True)),
+                ('latest_check', models.DateTimeField()),
+                ('return_value', models.CharField(blank=True, max_length=100)),
                 ('task', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='django_celery_beat.periodictask')),
             ],
         ),

cynomys/migrations/0002_deltas_return_value.py

-# Generated by Django 3.2.4 on 2021-06-24 13:23
-
-from django.db import migrations, models
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ('cynomys', '0001_initial'),
-    ]
-
-    operations = [
-        migrations.AddField(
-            model_name='deltas',
-            name='return_value',
-            field=models.CharField(blank=True, max_length=100),
-        ),
-    ]

cynomys/migrations/0003_auto_20210624_1757.py

-# Generated by Django 3.2.4 on 2021-06-24 17:57
-
-from django.db import migrations, models
-import django.db.models.deletion
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ('django_celery_beat', '0016_auto_20210624_1313'),
-        ('cynomys', '0002_deltas_return_value'),
-    ]
-
-    operations = [
-        migrations.CreateModel(
-            name='Delta',
-            fields=[
-                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
-                ('timestamp', models.DateTimeField(editable=False)),
-                ('success', models.BooleanField(blank=True, null=True)),
-                ('latest_check', models.DateTimeField()),
-                ('return_value', models.CharField(blank=True, max_length=100)),
-                ('task', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='django_celery_beat.periodictask')),
-            ],
-        ),
-        migrations.DeleteModel(
-            name='Deltas',
-        ),
-    ]

cynomys/tasks.py

@@ -2,10 +2,13 @@ from celery import shared_task
 import subprocess
 from django.utils import timezone
 import requests
-
+import logging
 from django_celery_beat.models import PeriodicTask
+from django.contrib.auth.models import User
 from cynomys.models import Delta
+from django.core.mail import send_mail
 
+logger = logging.getLogger()
 
 
 @shared_task
@@ -55,6 +58,42 @@ def check_http(host, timeout, httpcode, **kwargs):
 #@shared_task
 # def l4_check():
 #     pass
+@shared_task
+def notify_email(delta_id, attempts):
+    attempts -= 1
+
+    receivers = []
+    for user in User.objects.all():
+        receivers.append(user.email)
+
+    delta = Delta.objects.filter(id=delta_id).last()
+    task_status = "up" if delta.success else "down"
+
+    logger.debug("sending email; task: {}, to: {}".format(delta.task, receivers))
+    num = send_mail(
+        "[cynomys] New Status: {}, Task: {}".format(task_status, delta.task),
+        "Task: {}\nSuccess: {}\nReturn Value: {}\nTimestamp: {}\nLatest Check: {}".format(
+          delta.task, 
+          delta.success, 
+          delta.return_value, 
+          delta.timestamp.strftime("%d.%m.%Y, %H:%M:%S"), 
+          delta.latest_check.strftime("%d.%m.%Y, %H:%M:%S")
+        ),
+        None,
+        receivers,
+        fail_silently=False
+    )
+
+    # Email was sent, exit function
+    if num > 0:
+        logger.info("sent {} email to {}".format(num, receivers))
+        return
+    
+    # Email was not sent, retry
+    logger.error("failed to send email to {}, attempts left: {}".format(receivers, attempts))
+    if attempts > 0:
+        notify_email(receivers, delta_id, attempts)
+
 
 def check_delta(responsebool, return_value, parent_task):
     """Gets data from a check and compares it to the current state in the database. If a delta occurs, sends notifications"""
@@ -75,6 +114,7 @@ def check_delta(responsebool, return_value, parent_task):
             new_delta.save()
             print("Status Changed for " + parent_task.name + " to a Success! Sending Notification")
             #TODO put notification task
+            notify_email.delay(new_delta.pk, 3)
 
     else:
         delta = Delta.objects.filter(task=parent_task).last()
@@ -93,3 +133,4 @@ def check_delta(responsebool, return_value, parent_task):
             new_delta.save()
             print("Status Changed for " + parent_task.name + " to a Failure! Sending Notification")
             #TODO put notification task
+            notify_email.delay(new_delta.pk, 3)