improve client's lease monitoring

we monitor lease status too frequently (every 5s) which doesn't correspond to the default grpc keepalive which we just made longer.
Let's lighten the load a bit and poll less frequent, once in 30s.
Changed the info message about lease expiring soon to more friendly "ending in 5 minutes".
Also, use effective_begin_time + effective_duration for end time calculation. Once scheduled leases are implemented these may differ from begin_time and duration.

(cherry picked from commit 3f9449b)

Author: michalskrivanek

packages/jumpstarter/jumpstarter/client/grpc.py

@@ -114,6 +114,7 @@ class Lease(BaseModel):
     name: str
     selector: str
     duration: timedelta
+    effective_duration: timedelta | None = None
     client: str
     exporter: str
     conditions: list[kubernetes_pb2.Condition]
@@ -138,8 +139,12 @@ def from_protobuf(cls, data: client_pb2.Lease) -> Lease:
         else:
             exporter = ""
 
+        effective_duration = None
+        if data.HasField("effective_duration"):
+            effective_duration = data.effective_duration.ToTimedelta()
+
         effective_begin_time = None
-        if data.effective_begin_time:
+        if data.HasField("effective_begin_time"):
             effective_begin_time = data.effective_begin_time.ToDatetime(
                 tzinfo=datetime.now().astimezone().tzinfo,
             )
@@ -149,6 +154,7 @@ def from_protobuf(cls, data: client_pb2.Lease) -> Lease:
             name=name,
             selector=data.selector,
             duration=data.duration.ToTimedelta(),
+            effective_duration=effective_duration,
             client=client,
             exporter=exporter,
             effective_begin_time=effective_begin_time,

packages/jumpstarter/jumpstarter/client/lease.py

@@ -248,23 +248,21 @@ async def _wait_for_ready_connection(self, path: str):
     @asynccontextmanager
     async def monitor_async(self, threshold: timedelta = timedelta(minutes=5)):
         async def _monitor():
+            check_interval = 30  # seconds - check periodically for external lease changes
             while True:
                 lease = await self.get()
-                # TODO: use effective_end_time as the authoritative source for lease end time
-                if lease.effective_begin_time:
-                    end_time = lease.effective_begin_time + lease.duration
-                    remain = end_time - datetime.now(tz=datetime.now().astimezone().tzinfo)
+                if lease.effective_begin_time and lease.effective_duration:
+                    end_time = lease.effective_begin_time + lease.effective_duration
+                    remain = end_time - datetime.now().astimezone()
                     if remain < timedelta(0):
                         # lease already expired, stopping monitor
                         logger.info("Lease {} ended at {}".format(self.name, end_time))
                         break
-                    elif remain < threshold:
-                        # lease expiring soon, check again on expected expiration time in case it's extended
-                        logger.info("Lease {} ending soon in {} at {}".format(self.name, remain, end_time))
-                        await sleep(threshold.total_seconds())
-                    else:
-                        # lease still active, check again in 5 seconds
-                        await sleep(5)
+                    # Log once when entering the threshold window
+                    if threshold - timedelta(seconds=check_interval) <= remain < threshold:
+                        logger.info("Lease {} ending in {} minutes at {}".format(
+                            self.name, int((remain.total_seconds() + 30) // 60), end_time))
+                    await sleep(min(remain.total_seconds(), check_interval))
                 else:
                     await sleep(1)