R2-08 Async LDAP + HistoryRead (arch-review round 2) #435

2026-07-13T12:22:37-04:00

dohertj2 commented

2026-07-13 12:22:37 -04:00

Round-2 arch-review plan R2-08 (findings 03/S2, 03/S3).

03/S2: the OPC UA SDK raises the impersonation callback synchronously under a SessionManager-wide event lock, so one hung LDAP bind serializes every session activation. Fixed at the LdapOpcUaUserAuthenticator boundary: AuthTimeoutMs hard WaitAsync bound, MaxConcurrentAuthentications semaphore, ConnectionTimeoutMs, directory-outage circuit (OutageFailureThreshold/CooldownSeconds + half-open probe), LdapAuthResult.IsSystemFailure seam — all fail-closed.
03/S3: HistoryRead per-node sequential block-bridge async-ified (all 4 arms; OCE→BadTimeout), bounded per-node fan-out (RunBounded semaphore, single arm-boundary bridge), per-request deadline CTS, process-wide batch limiter (flood → BadTooManyOperations, cap 16×4=64).

All 14 tasks; T14 full-sweep + live legs (docker-dev unreachable-LDAP, Category=LiveIntegration soak) deferred to serial heavy pass. Build clean; Host.IntegrationTests LDAP 43, Security.Tests 11, OpcUaServer.Tests HistoryRead+Impersonation 37, Runtime.Tests ServerHistorianOptions 11 (all green). Plan: archreview/plans/R2-08-ldap-historyread-async-plan.md.

Round-2 arch-review plan **R2-08** (findings 03/S2, 03/S3). - **03/S2**: the OPC UA SDK raises the impersonation callback synchronously under a SessionManager-wide event lock, so one hung LDAP bind serializes every session activation. Fixed at the `LdapOpcUaUserAuthenticator` boundary: AuthTimeoutMs hard WaitAsync bound, MaxConcurrentAuthentications semaphore, ConnectionTimeoutMs, directory-outage circuit (OutageFailureThreshold/CooldownSeconds + half-open probe), `LdapAuthResult.IsSystemFailure` seam — all fail-closed. - **03/S3**: HistoryRead per-node sequential block-bridge async-ified (all 4 arms; OCE→BadTimeout), bounded per-node fan-out (RunBounded semaphore, single arm-boundary bridge), per-request deadline CTS, process-wide batch limiter (flood → BadTooManyOperations, cap 16×4=64). All 14 tasks; T14 full-sweep + live legs (docker-dev unreachable-LDAP, Category=LiveIntegration soak) deferred to serial heavy pass. Build clean; Host.IntegrationTests LDAP 43, Security.Tests 11, OpcUaServer.Tests HistoryRead+Impersonation 37, Runtime.Tests ServerHistorianOptions 11 (all green). Plan: `archreview/plans/R2-08-ldap-historyread-async-plan.md`.

dohertj2 added 14 commits 2026-07-13 12:22:38 -04:00

test(host): red repro — LDAP authenticator has no wall-clock bound on session activation (03/S2) ce6d9e21d3

feat(security): LDAP auth timeout/concurrency/outage-circuit options; project ConnectionTimeoutMs into the shared library (03/S2) 09faa05f06

feat(security): LdapAuthResult.IsSystemFailure distinguishes directory outage from credential deny (03/S2) 0d5cb89d48

feat(host): hard wall-clock bound + bounded concurrency on OPC UA LDAP authentication (03/S2) 21abe42a90

feat(host): LDAP directory-outage circuit — fail-fast denial during sustained outage (03/S2) 0c785415a2

test(host): unreachable-directory activation fails bounded; document the SDK impersonation threading contract (03/S2) 62a49779ac

test(opcuaserver): red repro — HistoryRead serves a batch strictly sequentially (03/S3) d5c6609cdf

feat(runtime): ServerHistorian HistoryRead parallelism/limiter/deadline knobs + node-manager wiring (03/S3) 304442dba4

refactor(opcuaserver): async-ify ServeNode + Processed/AtTime HistoryRead internals, thread cancellation (03/S3) 1e83fe7085

refactor(opcuaserver): async-ify ServeRawPaged + HistoryReadEvents internals (03/S3) cef7d9b281

feat(opcuaserver): bounded per-node parallel HistoryRead within a batch (03/S3) 8c365da754

feat(opcuaserver): per-request HistoryRead deadline — hung backends surface BadTimeout (03/S3) 888cf86655

feat(opcuaserver): process-wide HistoryRead batch limiter — flood degrades to BadTooManyOperations, not pool exhaustion (03/S3) 3cebfae417

docs: ServerHistorian HistoryRead knobs + Security:Ldap resilience keys; R2-08 status (03/S2, 03/S3)

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dohertj2 commented

2026-07-13 12:23:22 -04:00

Landed on master via merge commit a004931f (local --no-ff merge, clean build barrier). Full-sweep + live LDAP/gateway legs deferred to serial heavy pass. Closing as merged.

Landed on `master` via merge commit `a004931f` (local --no-ff merge, clean build barrier). Full-sweep + live LDAP/gateway legs deferred to serial heavy pass. Closing as merged.

dohertj2 closed this pull request

2026-07-13 12:23:23 -04:00

dohertj2 referenced this issue from a commit

2026-07-13 12:23:23 -04:00

Merge R2-08 Async LDAP + HistoryRead (arch-review round 2) [PR #435]

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Reference: dohertj2/lmxopcua#435