my harness for niri
retain only 3 days worth of metrics
+39
+39
src/metrics.ts
+39
src/metrics.ts
···
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let db: Database.Database
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const events: (MetricEvent & { id: number })[] = []
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const MAX_IN_MEMORY = 100
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+
const DEFAULT_METRICS_RETENTION_DAYS = 3
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const METRICS_PRUNE_INTERVAL_MS = 60 * 60_000
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+
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let pruneTimer: ReturnType<typeof setInterval> | null = null
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+
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function metricsRetentionDays(): number {
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const parsed = Number(process.env.METRICS_RETENTION_DAYS ?? DEFAULT_METRICS_RETENTION_DAYS)
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if (!Number.isFinite(parsed) || parsed <= 0) return DEFAULT_METRICS_RETENTION_DAYS
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return parsed
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}
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+
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function metricsRetentionCutoff(days = metricsRetentionDays()): string {
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return new Date(Date.now() - days * 24 * 60 * 60_000).toISOString()
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}
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+
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export function pruneOldMetrics(days = metricsRetentionDays()): number {
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if (!db) return 0
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+
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const cutoff = metricsRetentionCutoff(days)
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try {
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const result = db.prepare("delete from metrics where createdAt < ?").run(cutoff)
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const deleted = result.changes
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if (deleted > 0) {
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console.log(`[metrics] pruned ${deleted} rows older than ${days} days`)
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db.pragma("wal_checkpoint(PASSIVE)")
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}
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return deleted
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} catch (err) {
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console.error("[metrics] failed to prune old metrics:", err)
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return 0
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}
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}
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export function initMetricsDb(): void {
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try {
···
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create index if not exists idx_metrics_created on metrics(createdAt desc);
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create index if not exists idx_metrics_type_id on metrics(type, id desc);
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`)
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pruneOldMetrics()
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if (!pruneTimer) {
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pruneTimer = setInterval(() => {
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pruneOldMetrics()
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}, METRICS_PRUNE_INTERVAL_MS)
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if (typeof pruneTimer.unref === "function") pruneTimer.unref()
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}
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console.log("[metrics] ready")
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}
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