Merge ~d0ugal/maas:release-notifications-2.7 into maas:2.7

[Dougal Matthews]

Add release notifications to MAAS

This change adds a new release notification service which periodically
queries the configured simplestream and checks the metadata for any
release notifications.

The notifications are created for all users and if a user dismisses the
notification it will be resurfaced every six weeks.

[MAAS Lander (maas-lander)]

UNIT TESTS
-b release-notifications-2.7 lp:~d0ugal/maas/+git/maas into -b 2.7 lp:~maas-committers/maas

STATUS: FAILED
LOG: http://maas-ci.internal:8080/job/maas/job/branch-tester/8399/console
COMMIT: 31025099926be9973c6c0f822288e4e6480f0356

review: Needs Fixing

[MAAS Lander (maas-lander)]

UNIT TESTS
-b release-notifications-2.7 lp:~d0ugal/maas/+git/maas into -b 2.7 lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: b24f1ed88081e345d1c284bb34a2dbf8b37f1115

review: Approve

[Lee Trager (ltrager)]

See my 2.9 review - https://code.launchpad.net/~d0ugal/maas/+git/maas/+merge/391058

review: Disapprove

[MAAS Lander (maas-lander)]

UNIT TESTS
-b release-notifications-2.7 lp:~d0ugal/maas/+git/maas into -b 2.7 lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 65700e30160c4775641c70b4342cedef8824b53f

review: Approve

[MAAS Lander (maas-lander)]

UNIT TESTS
-b release-notifications-2.7 lp:~d0ugal/maas/+git/maas into -b 2.7 lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: cba291a35c2ced5dd49f66674fc7519f2f17f677

review: Approve

9963f27... by Dougal Matthews on 2020-10-07

Add release notifications to MAAS

This change adds a new release notification service which periodically
queries the configured simplestream and checks the metadata for any
release notifications.

The notifications are created for all users and if a user dismisses the
notification it will be resurfaced every six weeks.

(cherry picked from commit 2a342196f366aea386f3bc341f71786c43c94e0d)

[MAAS Lander (maas-lander)]

UNIT TESTS
-b release-notifications-2.7 lp:~d0ugal/maas/+git/maas into -b 2.7 lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 9963f27b772ccb33da83031cd2a3b2544941518b

review: Approve

[Lee Trager (ltrager)]

LGTM!

review: Approve

diff --git a/src/maasserver/bootresources.py b/src/maasserver/bootresources.py
index 3cf6c30..3cc3689 100644
--- a/src/maasserver/bootresources.py
+++ b/src/maasserver/bootresources.py
@@ -65,6 +65,7 @@ from maasserver.models import (
     Event,
     LargeFile,
 )
+from maasserver.release_notifications import ReleaseNotifications
 from maasserver.rpc import getAllClients
 from maasserver.utils import (
     absolute_reverse,
@@ -1129,6 +1130,10 @@ class BootResourceRepoWriter(BasicMirrorWriter):
                     % (product_name, supported_version)
                 )
                 return
+        if item["ftype"] == "notifications":
+            ReleaseNotifications(
+                data["release_notification"]
+            ).maybe_check_release_notifications()
         if (
             item["ftype"] == BOOT_RESOURCE_FILE_TYPE.ROOT_IMAGE
             and BOOT_RESOURCE_FILE_TYPE.SQUASHFS_IMAGE in items.keys()
diff --git a/src/maasserver/models/bootsource.py b/src/maasserver/models/bootsource.py
index 1a2717c..73526e6 100644
--- a/src/maasserver/models/bootsource.py
+++ b/src/maasserver/models/bootsource.py
@@ -115,4 +115,17 @@ class BootSource(CleanSave, TimestampedModel):
                     "labels": ["*"],
                 }
             )
+        # Always download all release notifications from the stream.
+        for release_notification in self.bootsourcecache_set.filter(
+            release="notifications"
+        ):
+            data["selections"].append(
+                {
+                    "os": release_notification.os,
+                    "release": release_notification.release,
+                    "arches": [release_notification.arch],
+                    "subarches": ["*"],
+                    "labels": ["*"],
+                }
+            )
         return data
diff --git a/src/maasserver/release_notifications.py b/src/maasserver/release_notifications.py
new file mode 100644
index 0000000..808c886
--- /dev/null
+++ b/src/maasserver/release_notifications.py
@@ -0,0 +1,124 @@
+# Copyright 2020 Canonical Ltd.  This software is licensed under the
+# GNU Affero General Public License version 3 (see the file LICENSE).
+
+"""Release Notifications for MAAS
+
+Checks for new MAAS releases in the images.maas.io stream and creates
+notifications for the user.
+"""
+
+from datetime import datetime, timedelta
+
+import attr
+from twisted.internet.defer import inlineCallbacks
+
+from maasserver.models import Config, Notification
+from maasserver.utils.orm import transactional
+from maasserver.utils.threads import deferToDatabase
+from provisioningserver.logger import get_maas_logger, LegacyLogger
+from provisioningserver.utils import version
+from provisioningserver.utils.twisted import asynchronous
+
+maaslog = get_maas_logger("release-notifications")
+log = LegacyLogger()
+
+RELEASE_NOTIFICATION_SERVICE_PERIOD = timedelta(hours=24)
+RESURFACE_AFTER = timedelta(weeks=6)
+RELEASE_NOTIFICATION_IDENT = "release_notification"
+
+
+@attr.s()
+class ReleaseNotification:
+    maas_version = attr.ib()
+    message = attr.ib()
+    # Product version number
+    version = attr.ib()
+
+
+class NoReleasenotification(LookupError):
+    pass
+
+
+def notification_available(notification_version, maas_version=None):
+    current_version = version.get_version_tuple(
+        maas_version or version.get_maas_version()
+    )
+    log.debug(f"Current MAAS version: {repr(current_version)}")
+    log.debug(f"Notification version: {notification_version}")
+
+    notification_version_tuple = version.get_version_tuple(
+        notification_version
+    )
+    return notification_version_tuple > current_version
+
+
+@transactional
+def ensure_notification_exists(message, resurface_after=RESURFACE_AFTER):
+
+    notification, created = Notification.objects.get_or_create(
+        ident=RELEASE_NOTIFICATION_IDENT,
+        defaults={
+            "message": message,
+            "category": "info",
+            "users": True,
+            "admins": True,
+        },
+    )
+    if created:
+        # Since this is a new notification there is nothing else to do. It will
+        # now be showen to all users
+        return
+
+    # Only the message will be updated in release notifications.
+    if notification.message != message:
+        notification.message = message
+        notification.save()
+        # If the notification is being updated, we want to resuface it for all
+        # users by deleting their dismissals
+        notification.notificationdismissal_set.all().delete()
+        return
+
+    if (datetime.now() - notification.updated) > resurface_after:
+        notification.notificationdismissal_set.all().delete()
+        # We are using save to update the `updated` field on the Notification
+        # model. This behaviour will be changed in MAAS 2.9 and above when
+        # we can update the schema and make the notification dismissal a
+        # timestamped model
+        notification.save(force_update=True)
+
+
+class ReleaseNotifications:
+    def __init__(self, release_notification):
+        self.release_notification = ReleaseNotification(**release_notification)
+
+    def maybe_check_release_notifications(self):
+        def check_config():
+            return Config.objects.get_config("release_notifications")
+
+        d = deferToDatabase(transactional(check_config))
+        d.addCallback(self.check_notifications)
+        d.addErrback(log.err, "Failure checking release notifications.")
+        return d
+
+    def cleanup_notification(self):
+        maaslog.debug("Cleaning up notifications")
+        Notification.objects.filter(ident=RELEASE_NOTIFICATION_IDENT).delete()
+
+    @asynchronous
+    @inlineCallbacks
+    def check_notifications(self, notifications_enabled):
+
+        if not notifications_enabled:
+            maaslog.debug("Release notifications are disabled")
+            # Notifications are disabled, we can delete any that currently exist.
+            yield deferToDatabase(transactional(self.cleanup_notification))
+            return
+
+        if not notification_available(self.release_notification.maas_version):
+            maaslog.debug("No new release notifications available")
+            return
+
+        maaslog.debug("Notification to display")
+        yield deferToDatabase(
+            ensure_notification_exists, self.release_notification.message
+        )
diff --git a/src/maasserver/tests/test_release_notifications.py b/src/maasserver/tests/test_release_notifications.py
new file mode 100644
index 0000000..c63f8b4
--- /dev/null
+++ b/src/maasserver/tests/test_release_notifications.py
@@ -0,0 +1,101 @@
+import datetime
+
+from maasserver import release_notifications
+from maasserver.models import Notification
+from maasserver.testing.testcase import (
+    MAASServerTestCase,
+    MAASTransactionServerTestCase,
+)
+
+
+class TestVersionCheck(MAASServerTestCase):
+    def test_new_release_available(self):
+        current_version = "2.8.1"
+        notification_maas_version = "2.9.0"
+        self.assertTrue(
+            release_notifications.notification_available(
+                notification_maas_version, current_version
+            )
+        )
+
+    def test_already_on_latest_version(self):
+        current_version = "2.9.0"
+        notification_maas_version = "2.9.0"
+        self.assertFalse(
+            release_notifications.notification_available(
+                notification_maas_version, current_version
+            )
+        )
+
+    def test_notification_is_old(self):
+        current_version = "2.9.0"
+        notification_maas_version = "2.8.0"
+        self.assertFalse(
+            release_notifications.notification_available(
+                notification_maas_version, current_version
+            )
+        )
+
+
+class TestReleaseNotification(MAASTransactionServerTestCase):
+    def _get_release_notifications(self):
+        return Notification.objects.filter(
+            ident=release_notifications.RELEASE_NOTIFICATION_IDENT
+        )
+
+    def test_create_notification(self):
+        """Test creating a new release notification"""
+
+        message = "Upgrade to version 3.14 today"
+        release_notifications.ensure_notification_exists(message)
+        original_notification = self._get_release_notifications().get()
+
+        release_notifications.ensure_notification_exists(message)
+
+        self.assertEqual(self._get_release_notifications().count(), 1)
+
+        notification = self._get_release_notifications().get()
+        self.assertEqual(message, notification.message)
+        self.assertEqual(notification.created, original_notification.created)
+        # As the notification hasn't changed, we don't want the updated datetime
+        # to be changed.
+        self.assertEqual(notification.updated, original_notification.updated)
+
+    def test_updating_notification(self):
+        """Test updating a release notification with a new message"""
+
+        message = "Upgrade to version 3.1 today"
+        release_notifications.ensure_notification_exists(message)
+        original_notification = self._get_release_notifications().get()
+
+        message = "Upgrade to version 3.2 today"
+        release_notifications.ensure_notification_exists(message)
+
+        self.assertEqual(self._get_release_notifications().count(), 1)
+
+        notification = self._get_release_notifications().get()
+        self.assertEqual(message, notification.message)
+        self.assertEqual(notification.created, original_notification.created)
+        self.assertGreater(notification.updated, original_notification.updated)
+
+    def test_resurface_notification(self):
+        """Test resufacing release notifications that were dismissed"""
+
+        message = "Upgrade to version 3.14 today"
+        release_notifications.ensure_notification_exists(message)
+
+        # Manually update the notification to appear in the past.
+        seven_weeks_ago = datetime.datetime.now() - datetime.timedelta(weeks=7)
+        self._get_release_notifications().update(
+            updated=seven_weeks_ago, created=seven_weeks_ago
+        )
+        original_notification = self._get_release_notifications().get()
+
+        release_notifications.ensure_notification_exists(message)
+
+        self.assertEqual(self._get_release_notifications().count(), 1)
+
+        notification = self._get_release_notifications().get()
+        self.assertEqual(message, notification.message)
+        self.assertEqual(notification.created, original_notification.created)
+        self.assertGreater(notification.updated, original_notification.updated)