Notes and documentation covering actors, remoting, clustering, persistence,
streams, serialization, hosting, testing, and best practices for the Akka.NET
framework used throughout the ScadaLink system.
Deployment Manager: add deployment concurrency rules (block same-instance, allow
parallel different-instance), per-site artifact deployment status, current-only
status persistence.
Central UI: specify Blazor Server framework, real-time push updates via SignalR
for debug view, health dashboard, and deployment status.
Site Event Logging: daily retention purge, paginated queries with 500-event default,
keyword search on message/source fields.
Store-and-Forward: clarify async best-effort replication to standby with acceptable
trade-offs on failover.
Expand SMTP configuration with OAuth2 Client Credentials support for Microsoft 365,
connection timeout, and max concurrent connections. Single email per send with all
recipients in BCC. Plain text only. Classify SMTP errors: transient (4xx/connection)
to S&F, permanent (5xx) returned to script. No app-level rate limiting.
Define POST /api/{methodName} URL structure with X-API-Key header. Flat JSON
request/response with no envelope wrapper. Add extended type system (Object, List)
for complex API parameters and return values, applied to both Inbound API and
External System Gateway method definitions. Only failures logged; no rate limiting
in this controlled industrial environment.
Replace Windows Integrated Auth with direct LDAP bind (username/password login form).
Add JWT-based sessions with HMAC-SHA256 shared key for load balancer compatibility.
15-minute token refresh re-queries LDAP for current group memberships. 30-minute
configurable idle timeout. LDAP failure: new logins fail, active sessions continue
with current roles until LDAP recovers.
Set 30-second report interval with 60-second absolute timeout for offline detection.
Define error rates as raw counts per interval (reset after each report). Script errors
include all failure types. Automatic online recovery on first received report. Flat
snapshot report structure.
Add keep-oldest split-brain resolver with 15s stable-after duration. Configure both
nodes as seed nodes for symmetric startup. Set moderate failure detection defaults
(2s heartbeat, 10s threshold, ~25s total failover). Document automatic dual-node
recovery from persistent storage with no manual intervention.
Add per-pattern message timeouts with sensible defaults (120s for deployments, 30s
for queries/commands). Configure Akka.NET transport heartbeat explicitly rather than
relying on framework defaults. Document per-site message ordering guarantee. Specify
that in-flight messages on disconnect result in timeout error (no central buffering)
and debug streams die on any disconnect.
Scripts now choose per invocation whether an external system call is synchronous
(all failures return to script) or cached (transient failures go to store-and-forward).
Mirrors the existing Database.Connection/CachedWrite pattern. Updated ESG, Site
Runtime script API, high-level requirements, and design doc.
Specify HTTP/REST with JSON as the invocation protocol. Add API key and Basic Auth
as outbound authentication modes. Add per-system call timeouts. Classify errors by
HTTP status for store-and-forward decisions (5xx/transient → retry, 4xx → permanent
error to script). Document ADO.NET connection pooling for database connections.
Update Store-and-Forward to clarify transient-only buffering.
Add connection lifecycle (fixed-interval auto-reconnect, immediate bad quality on
disconnect, transparent re-subscribe), synchronous write failure errors to scripts,
periodic tag path resolution retry, and enhanced health reporting with tag resolution
counts. Update cross-references in Health Monitoring and Site Runtime.
Audit logging was absorbed into the Configuration Database component (IAuditService),
making the separate Component-AuditLogging.md redundant. Also added tool usage
guidance to CLAUDE.md for Codex MCP model selection.
