Redundancy OTel Meter + RoleChanged SignalR push (#198) #141

dohertj2 · 2026-04-19T23:17:55-04:00

dohertj2 commented

2026-04-19 23:17:55 -04:00

Closes #198. New RedundancyMetrics (System.Diagnostics.Metrics.Meter with 3 ObservableGauges + role_transition Counter). FleetStatusPoller detects RedundancyRole changes, pushes RoleChanged to fleet-status hub, increments Counter. RedundancyTab subscribes + repaints + shows live banner. Exporter package (OTLP vs Prometheus) split to task #201. Admin 87/87 (+2 tests).

dohertj2 added 1 commit 2026-04-19 23:17:56 -04:00

OpenTelemetry redundancy metrics + RoleChanged SignalR push. Closes instrumentation + live-push slices of task #198 ; the exporter wiring (OTLP vs Prometheus package decision) is split to new task #201 because the collector/scrape-endpoint choice is a fleet-ops decision that deserves its own PR rather than hardcoded here. New RedundancyMetrics class (Singleton-registered in DI) owning a System.Diagnostics.Metrics.Meter("ZB.MOM.WW.OtOpcUa.Redundancy", "1.0.0"). Three ObservableGauge instruments — otopcua.redundancy.primary_count / secondary_count / stale_count — all tagged by cluster.id, populated by SetClusterCounts(clusterId, primary, secondary, stale) which the poller calls at the tail of every tick; ObservableGauge callbacks snapshot the last value set under a lock so the reader (OTel collector, dotnet-counters) sees consistent tuples. One Counter — otopcua.redundancy.role_transition — tagged cluster.id, node.id, from_role, to_role; ideal for tracking "how often does Cluster-X failover" + "which node transitions most" aggregate queries. In-box Metrics API means zero NuGet dep here — the exporter PR adds OpenTelemetry.Extensions.Hosting + OpenTelemetry.Exporter.OpenTelemetryProtocol or OpenTelemetry.Exporter.Prometheus.AspNetCore to actually ship the data somewhere. FleetStatusPoller extended with role-change detection. Its PollOnceAsync now pulls ClusterNode rows alongside the existing ClusterNodeGenerationState scan, and a new PollRolesAsync walks every node comparing RedundancyRole to the _lastRole cache. On change: records the transition to RedundancyMetrics + emits a RoleChanged SignalR message to both FleetStatusHub.GroupName(cluster) + FleetStatusHub.FleetGroup so cluster-scoped + fleet-wide subscribers both see it. First observation per node is a bootstrap (cache fill) + NOT a transition — avoids spurious churn on service startup or pod restart. UpdateClusterGauges groups nodes by cluster + sets the three gauge values, using ClusterNodeService.StaleThreshold (shared 30s convention) for staleness so the /hosts page + the gauge agree. RoleChangedMessage record lives alongside NodeStateChangedMessage in FleetStatusPoller.cs. RedundancyTab.razor subscribes to the fleet-status hub on first parameters-set, filters RoleChanged events to the current cluster, reloads the node list + paints a blue info banner ("Role changed on node-a: Primary → Secondary at HH:mm:ss UTC") so operators see the transition without needing to poll-refresh the page. IAsyncDisposable closes the connection on tab swap-away. Two new RedundancyMetricsTests covering RecordRoleTransition tag emission (cluster.id + node.id + from_role + to_role all flow through the MeterListener callback) + ObservableGauge snapshot for two clusters (assert primary_count=1 for c1, stale_count=1 for c2). Existing FleetStatusPollerTests ctor-line updated to pass a RedundancyMetrics instance; all tests still pass. Full Admin.Tests suite 87/87 passing (was 85, +2). Admin project builds 0 errors. Task #201 captures the exporter-wiring follow-up — OpenTelemetry.Extensions.Hosting + OTLP vs Prometheus + /metrics endpoint decision, driven by fleet-ops infra direction. 1f3343e61f

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

dohertj2 merged commit 42649ca7b0 into v2

2026-04-19 23:18:06 -04:00

dohertj2 referenced this issue from a commit

2026-04-19 23:18:07 -04:00

Merge pull request (#141) - Redundancy OTel + SignalR

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Reference: dohertj2/lmxopcua#141