Mebbling/lib/metrics.ts

import { db } from "@/lib/db";

const line = (name: string, value: number, labels = "") => `${name}${labels ? `{${labels}}` : ""} ${Number.isFinite(value) ? value : 0}`;
export function prometheusMetrics() {
  const count = (sql: string) => Number((db.prepare(sql).get() as { count: number }).count);
  const jobs = db.prepare("SELECT status,count(*) AS count FROM sync_jobs GROUP BY status").all() as { status: string; count: number }[];
  const alerts = db.prepare("SELECT status,count(*) AS count FROM alert_deliveries GROUP BY status").all() as { status: string; count: number }[];
  const queuedAge = Number((db.prepare("SELECT COALESCE(MAX(strftime('%s','now')-strftime('%s',created_at)),0) AS age FROM sync_jobs WHERE status='queued'").get() as { age: number }).age);
  const signed = count("SELECT count(*) AS count FROM sources WHERE is_enabled=1 AND webhook_mode='signed'"); const recentWebhook = count("SELECT count(*) AS count FROM sources WHERE is_enabled=1 AND webhook_mode='signed' AND last_webhook_at>=datetime('now','-24 hours')");
  const cacheRows = db.prepare("SELECT attachments_json FROM posts").all() as { attachments_json: string }[]; let cacheBytes = 0; for (const row of cacheRows) { try { cacheBytes += (JSON.parse(row.attachments_json) as { url?: string; size?: number }[]).filter((item) => item.url?.startsWith("/uploads/cache/")).reduce((sum, item) => sum + Number(item.size || 0), 0); } catch {} }
  return ["# HELP mebbling_sources_enabled Number of enabled sources", "# TYPE mebbling_sources_enabled gauge", line("mebbling_sources_enabled", count("SELECT count(*) AS count FROM sources WHERE is_enabled=1")), "# HELP mebbling_posts_public Number of visible public posts", "# TYPE mebbling_posts_public gauge", line("mebbling_posts_public", count("SELECT count(*) AS count FROM posts WHERE visibility='PUBLIC' AND hidden=0")), "# HELP mebbling_sync_jobs Number of sync jobs by status", "# TYPE mebbling_sync_jobs gauge", ...jobs.map((job) => line("mebbling_sync_jobs", job.count, `status=\"${job.status.replaceAll('"', '')}\"`)), "# HELP mebbling_alert_deliveries Alert deliveries by status", "# TYPE mebbling_alert_deliveries gauge", ...alerts.map((alert) => line("mebbling_alert_deliveries", alert.count, `status=\"${alert.status.replaceAll('"', '')}\"`)), line("mebbling_sync_queue_oldest_seconds", queuedAge), line("mebbling_signed_webhooks", signed), line("mebbling_signed_webhooks_recent_24h", recentWebhook), line("mebbling_attachment_cache_bytes", cacheBytes)].join("\n") + "\n";
}