Fix blank TPS: read tick timing from vanilla 'tick query' instead of spark

spark sends command output asynchronously, so its RCON responses are
empty and the sampler recorded null TPS/MSPT. Use the synchronous
vanilla 'tick query' as the primary source (treating paused/frozen idle
servers as healthy), keep spark as fallback, and route spark ping /
healthreport through the server console (mc-send-to-console) with the
log watcher capturing ping lines. Lag endpoint now falls back to the
freshest recorded ping sample.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

dashboard/src/app/api/lag/route.ts

@@ -40,7 +40,13 @@ export async function GET() {
 
     const serverHealthy = (tps === null || tps >= 18) && (mspt === null || mspt <= 40);
     const players = online.map((name) => {
-      const ping = livePings[name] ?? null;
+      // spark's RCON reply is often empty (async output) — fall back to the
+      // most recent logged sample if it's fresh enough.
+      const hist = historyByPlayer[name] ?? [];
+      const lastSample = hist.length > 0 ? hist[hist.length - 1] : null;
+      const ping =
+        livePings[name] ??
+        (lastSample && Date.now() - lastSample.ts < 5 * 60 * 1000 ? lastSample.ping : null);
       return {
         name,
         ping,

dashboard/src/server/logwatch.ts

@@ -26,6 +26,17 @@ function messageOf(line: string): string {
 
 function parseEvent(line: string, backfill: boolean) {
   const msg = messageOf(line).replace(/§[0-9a-fk-or]/gi, "");
+
+  // spark ping output routed through the console (see sampler fallback):
+  // "[⚡] Alice: 23ms"
+  const ping = msg.match(/\[⚡\]\s*([A-Za-z0-9_]{3,16}):\s*([\d.]+)\s*ms/);
+  if (ping && !backfill) {
+    db()
+      .prepare("INSERT INTO ping_samples(ts, player, ping) VALUES(?, ?, ?)")
+      .run(Date.now(), ping[1], Math.round(Number(ping[2])));
+    return;
+  }
+
   const emit = (type: string, player?: string, detail?: string) => {
     if (backfill) return; // don't re-record history after a panel restart
     logActivity(type, player, detail);

dashboard/src/server/mc.ts

@@ -1,4 +1,6 @@
 import { rcon, stripColors, RconError } from "./rcon";
+import { execInContainer } from "./docker";
+import { env } from "./env";
 
 /**
  * Game-level operations on top of RCON: player list, whitelist, EasyAuth
@@ -93,6 +95,38 @@ export async function easyauthSetPassword(name: string, password: string): Promi
 
 export type TpsSample = { tps: number | null; mspt: number | null };
 
+/**
+ * Primary TPS/MSPT source: vanilla `tick query`. Unlike spark, its output is
+ * returned synchronously over RCON. Typical output:
+ *   "The game is running normally / Target tick rate: 20.0 per second. /
+ *    Average time per tick: 2.1ms (Target: 50.0ms) ..."
+ */
+export async function tickQueryTps(): Promise<TpsSample | null> {
+  const out = stripColors(await rcon().exec("tick query"));
+  const target = Number(out.match(/tick rate:\s*([\d.]+)/i)?.[1]) || 20;
+  if (/paused|frozen/i.test(out)) {
+    // pause-when-empty idle state — the server is keeping up by definition
+    return { tps: target, mspt: null };
+  }
+  const mspt = out.match(/per tick:\s*([\d.]+)\s*ms/i);
+  if (!mspt) return null;
+  const ms = Number(mspt[1]);
+  const tps = ms > 0 ? Math.min(target, 1000 / ms) : target;
+  return { tps: Math.round(tps * 10) / 10, mspt: ms };
+}
+
+/** TPS with fallback chain: tick query → spark → nulls. */
+export async function queryTps(): Promise<TpsSample> {
+  try {
+    const t = await tickQueryTps();
+    if (t) return t;
+  } catch (err) {
+    if (err instanceof RconError) return { tps: null, mspt: null };
+    throw err;
+  }
+  return sparkTps();
+}
+
 export async function sparkTps(): Promise<TpsSample> {
   try {
     const out = stripColors(await rcon().exec("spark tps"));
@@ -127,5 +161,15 @@ export async function sparkPings(): Promise<Record<string, number>> {
 }
 
 export async function sparkHealthReport(): Promise<string> {
-  return stripColors(await rcon().exec("spark healthreport"));
+  const out = stripColors(await rcon().exec("spark healthreport"));
+  if (out.trim()) return out;
+  // spark replies asynchronously; over RCON the response is often empty.
+  // Route the command through the server's real console instead — the report
+  // then shows up in the live log.
+  try {
+    await execInContainer(env.mcContainer, ["mc-send-to-console", "spark", "healthreport"], 15_000);
+    return "spark replies asynchronously, so the report can't be captured here.\nIt was sent to the server console instead — open the Console page to read it (takes a few seconds).";
+  } catch {
+    return "spark did not return output over RCON, and sending to the server console failed.";
+  }
 }

dashboard/src/server/sampler.ts

@@ -1,7 +1,7 @@
 import fs from "node:fs";
 import { execFile } from "node:child_process";
-import { inspectContainer, containerStats } from "./docker";
+import { inspectContainer, containerStats, execInContainer } from "./docker";
-import { listOnlinePlayers, sparkTps, sparkPings } from "./mc";
+import { listOnlinePlayers, queryTps, sparkPings } from "./mc";
 import { db } from "./db";
 import { bus } from "./bus";
 import { notify } from "./notify";
@@ -72,9 +72,9 @@ async function sampleTick(state: SamplerState) {
       players = (await listOnlinePlayers()).online;
     } catch {}
 
-    // spark TPS every 3rd tick (30s)
+    // TPS every 3rd tick (30s) — vanilla `tick query`, spark as fallback
     if (state.tick % 3 === 0) {
-      const t = await sparkTps();
+      const t = await queryTps();
       state.cachedTps = t.tps;
       state.cachedMspt = t.mspt;
       if (t.tps !== null && t.tps < 15) {
@@ -89,10 +89,17 @@ async function sampleTick(state: SamplerState) {
     }
 
     // per-player pings every 6th tick (60s)
-    if (state.tick % 6 === 0) {
+    if (state.tick % 6 === 0 && (players ?? 0) > 0) {
       const pings = await sparkPings();
-      const insert = db().prepare("INSERT INTO ping_samples(ts, player, ping) VALUES(?, ?, ?)");
+      if (Object.keys(pings).length > 0) {
-      for (const [player, ping] of Object.entries(pings)) insert.run(ts, player, ping);
+        const insert = db().prepare("INSERT INTO ping_samples(ts, player, ping) VALUES(?, ?, ?)");
+        for (const [player, ping] of Object.entries(pings)) insert.run(ts, player, ping);
+      } else {
+        // spark replies asynchronously, so RCON often gets an empty response.
+        // Fall back to sending the command to the server console; the output
+        // lands in the log and the log watcher records the pings from there.
+        void execInContainer(env.mcContainer, ["mc-send-to-console", "spark", "ping"], 15_000).catch(() => {});
+      }
     }
   } else {
     state.cachedTps = null;