Joseph Doherty
712c5117ee
Prerequisite for OtOpcUa Warm redundancy (lmxopcua#717): a Warm standby keeps a
healthy session but serves BadOutOfService at a standby ServiceLevel (90/50, boot 1),
so a connection that lands there sat on Bad quality forever.
- OPC UA connections with a backup poll Server_ServiceLevel (i=2267) on the connected
endpoint (IServiceLevelReadable, implemented by OpcUaDataConnection; never raises
Disconnected). A level < 200 sustained for the degraded window (default 10 s), or
the first sample after any (re)connect, triggers a probe of the other endpoint
(short-lived session: connect, read, dispose). Switch only when it reports a
Healthy (>= 200) higher level, and not within the minimum dwell (default 60 s) of
the previous ServiceLevel switch. Both degraded, other unreachable or level
unknown: stay put. 250/240 (today's OtOpcUa) never starts a streak.
- The switch reuses the failover path: SwitchToOtherEndpoint() now shared by all
three triggers, then BecomeReconnecting(ReconnectCause.ServiceLevelFailover) -
zero delay, no unstable accounting, ReSubscribeAll on the new endpoint.
- Config: OpcUaEndpointConfig.ServiceLevelFailover {enabled, degradedWindowSeconds,
minDwellSeconds}, read from the PRIMARY endpoint's JSON only; null = defaults
(enabled, 10, 60). Inside the encrypted protocol JSON, so no schema change or
migration. Central UI: fields in the Backup card next to Failover Retry Count.
Global: ScadaBridge:DataConnection:ServiceLevelPollInterval (2 s) and
ServiceLevelProbeTimeout (15 s).
- Tests: actor tests per trigger/non-trigger with positive controls, an unsolicited
promotion RefreshStart/RefreshEnd test at client and actor level, adapter tests,
and a real in-process OPC UA server pair end to end. All 15 mutants killed.
- Docs: Component-DataConnectionLayer, components/DataConnectionLayer, Component-CLI.
Claude-Session: https://claude.ai/code/session_01GT67ACmpMR7b9LGRPLijMi
Component Reference Documentation
Developer-reference docs for each ScadaBridge component, describing how the shipped
code in src/ actually works — with real code examples. These complement the
design specs in docs/requirements/: the specs say what a
component should do and why; these docs say how the code does it.
Reference docs exist for all 27 components (plus the shared TreeView, listed below).
| # | Component | Description |
|---|---|---|
| 1 | Template Engine | Template modeling, inheritance, composition, flattening, diffs, and semantic validation as implemented by the engine's services. |
| 2 | Deployment Manager | The central deployment pipeline: deployment identity and idempotency, per-instance operation locks, state transitions, all-or-nothing site apply, and artifact deployment. |
| 3 | Site Runtime | The site actor hierarchy (Deployment Manager singleton, Instance, Script, and Alarm actors), script compilation and execution, the site-wide stream, native alarms, and supervision. |
| 4 | Data Connection Layer | Protocol adapters (OPC UA, MxGateway), the Become/Stash connection state machine, reconnect and re-subscribe, and the native-alarm subscription seam. |
| 5 | Central–Site Communication | ClusterClient command and control plus gRPC server-streaming, the central and site communication actors, receptionist registration, and per-site contact points. |
| 6 | Store-and-Forward Engine | Site-only buffering, fixed-interval retry, parking, SQLite persistence, standby replication, and the operation-tracking store. |
| 7 | External System Gateway | Script-facing HTTP/REST and database access, the Call and CachedCall modes, and transient versus permanent error classification. |
| 8 | Notification Service | Central notification-list and SMTP definitions, the per-type delivery adapters, and OAuth2 or Basic SMTP delivery. |
| 9 | Central UI | The Blazor Server app structure, authentication, real-time updates (SignalR and gRPC), and the management pages. |
| 10 | Security & Auth | LDAP bind authentication, cookie and JWT sessions, role-based and site-scoped authorization, and shared Data Protection keys. |
| 11 | Health Monitoring | Site metric collection and central aggregation, report and heartbeat intervals, offline detection, and dead-letter monitoring. |
| 12 | Site Event Logging | The site-local SQLite event log, retention and storage cap, daily purge, and paginated central query access. |
| 13 | Cluster Infrastructure | The ClusterOptions model and validation for active/standby clustering, split-brain resolution, and failover. |
| 14 | Inbound API | POST /api/{method} script invocation, API-key authentication, the extended type system, and inbound-request auditing. |
| 15 | Host | The deployable binary: role-based component registration, Akka bootstrap, ASP.NET Core hosting, and the readiness and active-node health endpoints. |
| 16 | Commons | Shared POCO entities, repository and service interfaces, message contracts, and the Types/Interfaces/Entities/Messages namespace layout. |
| 17 | Configuration Database | The EF Core DbContext, repository implementations, the audit service, secret encryption, and migration and partition maintenance. |
| 18 | Management Service | The ManagementActor admin command surface, its HTTP endpoints, and ClusterClientReceptionist registration. |
| 19 | CLI | The System.CommandLine tool over the HTTP Management API — its command groups, config file, and output formats. |
| 20 | Traefik Proxy | The reverse proxy fronting the central cluster, active-node routing via /health/active, and the Docker topology configuration. |
| 21 | Notification Outbox | The central NotificationOutboxActor, the Notifications table, the dispatcher loop, retry and parking, and KPIs. |
| 22 | Site Call Audit | The central SiteCallAuditActor, the SiteCalls mirror table, telemetry ingest, and the parked-call Retry/Discard relay. |
| 23 | Audit Log | The append-only audit store: site SQLite hot-path, gRPC telemetry, central ingest and reconciliation, redaction, retention, and KPIs. |
| 24 | Transport | Encrypted bundle export and import, dependency resolution, conflict detection, and BundleImportId-correlated audit. |
| 25 | Script Analysis | The script trust model and validator, the diagnostics-only compile gate, the blocking-wait advisory, and the static flow-shape predictor. |
| 26 | KPI History | The central KpiHistoryRecorderActor singleton: KPI sampling, hourly rollups and backfill, and retention purge. |
| 27 | Delmia Notifier | The WWNotifier console client DELMIA shells out to, its YES/NO contract, and pre-execution-only failover. |
| 28 | Tree View | The reusable Blazor tree component — parameters, selection modes, and usage in the Central UI. |
Related Documentation
- Component design specs — the spec each component implements.
- Documentation Style Guide — the writing conventions these docs follow.
- README — the repository master index.