implemented "lease_renewal" attribute as calculated value within what period of time the license must be renewed

app/main.py

@@ -9,7 +9,7 @@ from dotenv import load_dotenv
 from fastapi import FastAPI
 from fastapi.requests import Request
 from json import loads as json_loads
-from datetime import datetime
+from datetime import datetime, timedelta
 from dateutil.relativedelta import relativedelta
 from calendar import timegm
 from jose import jws, jwk, jwt, JWTError
@@ -43,6 +43,7 @@ INSTANCE_KEY_PUB = load_key(str(env('INSTANCE_KEY_PUB', join(dirname(__file__),
 TOKEN_EXPIRE_DELTA = relativedelta(days=int(env('TOKEN_EXPIRE_DAYS', 1)), hours=int(env('TOKEN_EXPIRE_HOURS', 0)))
 LEASE_EXPIRE_DELTA = relativedelta(days=int(env('LEASE_EXPIRE_DAYS', 90)), hours=int(env('LEASE_EXPIRE_HOURS', 0)))
 LEASE_RENEWAL_PERIOD = float(env('LEASE_RENEWAL_PERIOD', 0.15))
+LEASE_RENEWAL_DELTA = timedelta(days=int(env('LEASE_EXPIRE_DAYS', 90)), hours=int(env('LEASE_EXPIRE_HOURS', 0)))
 CORS_ORIGINS = str(env('CORS_ORIGINS', '')).split(',') if (env('CORS_ORIGINS')) else [f'https://{DLS_URL}']
 
 jwt_encode_key = jwk.construct(INSTANCE_KEY_RSA.export_key().decode('utf-8'), algorithm=ALGORITHMS.RS256)
@@ -151,7 +152,8 @@ async def _origins(request: Request, leases: bool = False):
     for origin in session.query(Origin).all():
         x = origin.serialize()
         if leases:
-            x['leases'] = list(map(lambda _: _.serialize(), Lease.find_by_origin_ref(db, origin.origin_ref)))
+            serialize = dict(renewal_period=LEASE_RENEWAL_PERIOD, renewal_delta=LEASE_RENEWAL_DELTA)
+            x['leases'] = list(map(lambda _: _.serialize(**serialize), Lease.find_by_origin_ref(db, origin.origin_ref)))
         response.append(x)
     session.close()
     return JSONr(response)
@@ -168,7 +170,8 @@ async def _leases(request: Request, origin: bool = False):
     session = sessionmaker(bind=db)()
     response = []
     for lease in session.query(Lease).all():
-        x = lease.serialize()
+        serialize = dict(renewal_period=LEASE_RENEWAL_PERIOD, renewal_delta=LEASE_RENEWAL_DELTA)
+        x = lease.serialize(**serialize)
         if origin:
             lease_origin = session.query(Origin).filter(Origin.origin_ref == lease.origin_ref).first()
             if lease_origin is not None:

app/orm.py

@@ -81,7 +81,7 @@ class Lease(Base):
     def __repr__(self):
         return f'Lease(origin_ref={self.origin_ref}, lease_ref={self.lease_ref}, expires={self.lease_expires})'
 
-    def serialize(self) -> dict:
+    def serialize(self, renewal_period: float, renewal_delta: datetime.timedelta) -> dict:
         return {
             'lease_ref': self.lease_ref,
             'origin_ref': self.origin_ref,
@@ -89,6 +89,7 @@ class Lease(Base):
             'lease_created': self.lease_created.isoformat(),
             'lease_expires': self.lease_expires.isoformat(),
             'lease_updated': self.lease_updated.isoformat(),
+            'lease_renewal': Lease.calculate_renewal(renewal_period, renewal_delta),
         }
 
     @staticmethod
@@ -156,6 +157,19 @@ class Lease(Base):
         session.close()
         return deletions
 
+    @staticmethod
+    def calculate_renewal(renewal_period: float, delta: datetime.timedelta):
+        """
+        LEASE_RENEWAL_PERIOD=0.2  # 20%
+        delta = datetime.timedelta(days=1)
+        renew = delta.total_seconds() * LEASE_RENEWAL_PERIOD
+        renew = timedelta(seconds=renew)
+        expires = delta - renew  # 19.2
+        """
+        renew = delta.total_seconds() * renewal_period
+        renew = datetime.timedelta(seconds=renew)
+        return delta - renew
+
 
 def init(engine: Engine):
     tables = [Origin, Lease]