feat(sessions): add UnattachedSessionGraceSeconds to reap never-subscribed idle sessions

A client that opens a session and vanishes before it ever streams (e.g.
OtOpcUa's GalaxyDriver on a failed start) pinned a session slot and a live
x86 worker for the full DefaultLeaseSeconds (1800 s), because detach-grace
only applies to sessions that once had a subscriber.

MxGateway:Sessions:UnattachedSessionGraceSeconds (int, default 0 = off,
validated >= 0) makes the existing lease sweep reap a Ready session that
has never attached an event subscriber once it has been idle (no unary
activity) for the window, with the close reason unattached-grace-expired.
Ready-only, idle-from-last-activity and first-subscriber-cancels keep it
from catching slow starts or unary-only clients.

GatewaySession.ExtendLease had no production callers and did not fit the
rule, so it is removed; tests move leases through TouchClientActivity.

This commit is contained in:

Joseph Doherty

2026-10-22 06:31:39 -04:00

parent 2b165cd3a4

commit 285ef64160

9 changed files with 258 additions and 35 deletions

									
										src/ZB.MOM.WW.MxGateway.Server/appsettings.json
									
		+1
		
												View File
												
				@@ -51,6 +51,7 @@

				      "DefaultLeaseSeconds": 1800,

				      "LeaseSweepIntervalSeconds": 30,

				      "DetachGraceSeconds": 30,

				      "UnattachedSessionGraceSeconds": 0,

				      "AllowMultipleEventSubscribers": false,

				      "MaxEventSubscribersPerSession": 8

				    },