Add ExpiringEvents to count number events within a type window

tests/test_job_monitor.py

+
+import pytest
+import time
+
+from webservice.job_monitor import ExpiringEvents
+
+
+def test_expiring_events():
+    ev = ExpiringEvents(600)
+
+    assert ev.add() == 1
+    assert ev.add() == 2
+    assert ev.add(time.monotonic() - 800) == 2
+    assert ev.add() == 3
+
+    assert len(ev) == 3

webservice/job_monitor.py

@@ -7,6 +7,8 @@ import os.path
 import shlex
 import signal
 import time
+from bisect import insort_left
+from collections import deque
 from datetime import datetime, timezone
 from pathlib import Path
 from subprocess import run, PIPE
@@ -38,6 +40,33 @@ STATE_ABBREVS = {
 }
 
 
+class ExpiringEvents:
+    """Track events occuring within a time window.
+
+    Args:
+        window (int, optional): Time window in seconds, 600 by default.
+    """
+
+    def __init__(self, window=600):
+        self.window = window
+        self.events = deque()
+
+    def add(self, event=None):
+        now = time.monotonic()
+
+        insort_left(self.events, event or now)
+
+        cutoff = now - self.window
+
+        while self.events and self.events[0] < cutoff:
+            self.events.popleft()
+
+        return len(self.events)
+
+    def __len__(self):
+        return len(self.events)
+
+
 class NoOpProducer:
     """Fills in for Kafka producer object when setting that up fails"""
     def send(self, topic, value):