Created helper constructor for MonkeyTTL to make it more friendly to use

CR comment

monkey/monkey_island/cc/models/monkey_ttl.py

@@ -1,3 +1,5 @@
+from datetime import datetime, timedelta
+
 from mongoengine import Document, DateTimeField
 
 
@@ -6,11 +8,21 @@ class MonkeyTtl(Document):
     This model represents the monkey's TTL, and is referenced by the main Monkey document.
     See https://docs.mongodb.com/manual/tutorial/expire-data/ and
     https://stackoverflow.com/questions/55994379/mongodb-ttl-index-doesnt-delete-expired-documents/56021663#56021663
-    for more information about how TTL indexing works.
-
-    When initializing this object, do it like so:
-    t = MonkeyTtl(expire_at=datetime.utcnow() + timedelta(seconds=XXX))
+    for more information about how TTL indexing works and why this class is set up the way it is.
     """
+
+    def __init__(self, expiry_in_seconds, *args, **values):
+        """
+        Initializes a TTL object which will expire in expire_in_seconds seconds from when created.
+        Remember to call .save() on the object after creation.
+        :param expiry_in_seconds: How long should the TTL be in the DB, in seconds. Please take into consideration
+        that the cleanup thread of mongo might take extra time to delete the TTL from the DB.
+        """
+        # Using UTC to make the mongodb TTL feature work. See
+        # https://stackoverflow.com/questions/55994379/mongodb-ttl-index-doesnt-delete-expired-documents.
+        super(MonkeyTtl, self).__init__(
+            expire_at=datetime.utcnow() + timedelta(seconds=expiry_in_seconds), *args, **values)
+
     meta = {
         'indexes': [
             {

monkey/monkey_island/cc/models/test_monkey.py

@@ -21,7 +21,7 @@ class TestMonkey(TestCase):
     """
     def test_is_dead(self):
         # Arrange
-        alive_monkey_ttl = MonkeyTtl(expire_at=datetime.now() + timedelta(seconds=30))
+        alive_monkey_ttl = MonkeyTtl(30)
         alive_monkey_ttl.save()
         alive_monkey = Monkey(
             guid=str(uuid.uuid4()),
@@ -30,7 +30,7 @@ class TestMonkey(TestCase):
         alive_monkey.save()
 
         # MIA stands for Missing In Action
-        mia_monkey_ttl = MonkeyTtl(expire_at=datetime.now() + timedelta(seconds=30))
+        mia_monkey_ttl = MonkeyTtl(30)
         mia_monkey_ttl.save()
         mia_monkey = Monkey(guid=str(uuid.uuid4()), dead=False, ttl_ref=mia_monkey_ttl)
         mia_monkey.save()

monkey/monkey_island/cc/resources/monkey.py

@@ -19,9 +19,7 @@ __author__ = 'Barak'
 
 def create_monkey_ttl():
     # The TTL data uses the new `models` module which depends on mongoengine.
-    # Using UTC to make the mongodb TTL feature work. See
-    # https://stackoverflow.com/questions/55994379/mongodb-ttl-index-doesnt-delete-expired-documents.
-    current_ttl = MonkeyTtl(expire_at=datetime.utcnow() + timedelta(seconds=MONKEY_TTL_EXPIRY_DURATION_IN_SECONDS))
+    current_ttl = MonkeyTtl(MONKEY_TTL_EXPIRY_DURATION_IN_SECONDS)
     current_ttl.save()
     ttlid = current_ttl.id
     return ttlid