Instances also leave gracefully: a service shutting down should announce its departure rather than wait to expire, so callers stop routing to it immediately. deregister removes an instance from the pool at once. It must be safe to call on an instance (or service) that isn't there, so a double-deregister or a stale call never raises.
Add graceful removal:
deregister(service, instance_id): remove the instance from its service if present; do nothing (no error) if it isn't.class ServiceRegistry:
def __init__(self, ttl=10):
self.ttl = ttl
self.instances = {}
self._rr = {}
def register(self, service, instance_id, now):
self.instances.setdefault(service, {})[instance_id] = now
def healthy(self, service, now):
svc = self.instances.get(service, {})
return sorted(i for i, last in svc.items() if now - last <= self.ttl)
def heartbeat(self, service, instance_id, now):
svc = self.instances.get(service, {})
if instance_id in svc:
svc[instance_id] = now
return True
return False
def deregister(self, service, instance_id):
"""Remove an instance immediately; a no-op if it isn't registered."""
# TODO: self.instances.get(service, {}).pop(instance_id, None)
pass
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Instances also leave gracefully: a service shutting down should announce its departure rather than wait to expire, so callers stop routing to it immediately. deregister removes an instance from the pool at once. It must be safe to call on an instance (or service) that isn't there, so a double-deregister or a stale call never raises.
Add graceful removal:
deregister(service, instance_id): remove the instance from its service if present; do nothing (no error) if it isn't.Press Run Tests or ⌘↩ to check your solution.