const matchesInProgress = new prometheus.Gauge({ name: 'game_matches_active', help: 'Active matches', labelNames: ['game_mode'] });

// Performance metrics const tickDuration = new prometheus.Histogram({ name: 'game_tick_duration_seconds', help: 'Game loop tick duration', buckets: [0.001, 0.005, 0.01, 0.016, 0.033] });

const networkLatency = new prometheus.Histogram({ name: 'game_network_latency_ms', help: 'Player network latency', labelNames: ['region'], buckets: [10, 25, 50, 75, 100, 150, 200] });


## Alert Rules

```yaml
groups:
- name: game-alerts
  rules:
  - alert: GameServerDown
    expr: up{job="game-servers"} == 0
    for: 1m
    labels:
      severity: critical

  - alert: HighTickLatency
    expr: histogram_quantile(0.99, game_tick_duration_seconds) > 0.02
    for: 5m
    labels:
      severity: high

  - alert: LowPlayerCount
    expr: game_active_players < 10
    for: 10m
    labels:
      severity: warning

Target Thresholds

Metric	Target	Alert
Tick Rate	60 Hz	< 55 Hz
Latency P99	< 100ms	> 200ms
Memory	< 80%	> 90%
CPU	< 70%	> 85%

Troubleshooting

Common Failure Modes

Error	Root Cause	Solution
Missing metrics	Scrape failure	Check targets
Alert storms	Too sensitive	Tune thresholds
Dashboard slow	Too many queries	Aggregate
Gaps in data	Network issues	Add redundancy

Debug Checklist

# Check Prometheus targets
curl localhost:9090/api/v1/targets | jq '.data.activeTargets'

# Check firing alerts
curl localhost:9090/api/v1/alerts | jq '.data.alerts'

# Query metrics
curl 'localhost:9090/api/v1/query?query=game_active_players'

Unit Test Template

describe('Metrics', () => {
  test('records tick duration', async () => {
    const end = tickDuration.startTimer();
    await sleep(10);
    end();

    const metrics = await prometheus.register.metrics();
    expect(metrics).toContain('game_tick_duration_seconds');
  });
});

Resources

assets/ - Dashboard configs
references/ - Alerting guides

monitoring

Server Monitoring

Key Game Metrics