Joseph Doherty
b5f120c370
scadabridge_site_connection_up never counted data connections. It counts open central->site gRPC subscriber streams (Debug View + the site-wide alarm feed), so it correctly reads 0 on a healthy site nobody is watching — and the name invited reading it as device health. That misreading has already cost a live debugging session: register row 48's 'connection_up is 0 on all six site nodes' was healthy steady state, not the fault it was diagnosed as. Two halves, per the row: RENAME. scadabridge.site.connection.up -> scadabridge.site.stream.subscribers.active (helpers SiteConnectionOpened/Closed -> SiteStreamSubscriberOpened/Closed), and the instrument gains the unit:"1" the other gauges already carried. Every reference updated: the gRPC server, both test suites, Component-Communication.md, components/Commons.md, docker/README.md and docker/seed-live-probe.sh. A test now pins the new name AND asserts the old one is gone, so it cannot creep back. NEW. scadabridge.site.data_connections.connected / .total — the first exported data-connection signal (the state existed on the health report and in the CLI, but never as a metric). connected < total is the alert condition; neither number alone separates 'a device is down' from 'nothing is configured', which is why the denominator ships with the numerator. Sourcing is deliberate on two counts. It is fed by the DCL at its four state transitions rather than derived from the health report, so the metric survives a dead report pipeline — the exact failure the 'metrics stale' flag exists to catch, and a derived gauge would go blind at the same moment. And it uses a static registry reached through ScadaBridgeTelemetry (the SiteConnectionOpened precedent) rather than a DI-injected holder: the DCL actors already take ISiteHealthCollector through their constructors, and threading a second dependency through both would ripple into every test that builds them. It also keeps SiteHealthCollector untouched, which matters right now — another agent is concurrently editing that file for the tag-resolution path. Removal is wired too: an undeployed connection leaves the registry, so it stops counting toward the total instead of latching connected < total on forever. Both gauges read 0 on the standby (connections open on the active node only) — healthy, documented, and called out in the docs so it does not become the next site_connection_up. No ObservedMeters allowlist change: all three instruments ride the existing ZB.MOM.WW.ScadaBridge meter. (An unlisted meter exports nothing, silently.) Tests: Commons 711 passed (9 new, delta-based against a baseline with unique per-test connection names, so they do not inherit the register row 32 QueueDepthGaugeTests static-state flake); Communication 717; DCL 319.
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 24 of the 27 components (plus the shared TreeView, listed below). ScriptAnalysis (#25), KpiHistory (#26), and DelmiaNotifier (#27) are pending — tracked in ../plans/2026-07-08-deferred-work-register.md.
| # | 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 | 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.