Files
dashback/src/services/healthMonitorService.js
2026-10-19 01:53:25 +02:00

261 lines
8.7 KiB
JavaScript

// #region Imports & Configuration
import http from 'node:http';
import Redis from 'ioredis';
import env from '../config/env.js';
import { createLogger } from '../util/logger.js';
const healthLog = createLogger('health-monitor');
let scheduledTimer = null;
let scheduledInterval = null;
let aggregateInterval = null;
let isServiceRunning = false;
let redisClient = null;
const RAW_RETENTION_MS = 3 * 60 * 60 * 1000;
const AGGREGATE_WINDOW_MS = 4 * 60 * 60 * 1000;
const AGGREGATE_INTERVAL_MS = 30 * 60 * 1000;
const AGGREGATE_RETENTION_MS = 30 * 24 * 60 * 60 * 1000;
// MARK: redis sorted-set keys (score = unix ms timestamp, member = "<ts>:<value>")
export const rawKey = () => `${env.redis.key}:raw`;
export const avgKey = () => `${env.redis.key}:avg`;
export const maxKey = () => `${env.redis.key}:max`;
// #endregion
// #region Redis Client Management
// MARK: resolves or creates the lazy Redis client
export function getRedisClient() {
if (!redisClient) {
const opts = env.redis.url
? env.redis.url
: {
host: env.redis.host,
port: env.redis.port,
password: env.redis.password || undefined,
db: env.redis.db || 0,
lazyConnect: true,
enableReadyCheck: false,
maxRetriesPerRequest: 1,
retryStrategy(times) {
return Math.min(times * 1000, 30000);
},
};
redisClient = new Redis(opts);
redisClient.on('error', (err) => {
healthLog.warn(`Redis connection error: ${err.message}`);
});
}
return redisClient;
}
// #endregion
// #region TCP Health API Selftest
// MARK: executes an HTTP GET /health call over TCP loopback and measures response time
export function performHealthSelftest() {
return new Promise((resolve, reject) => {
const start = performance.now();
const req = http.request(
{
hostname: '127.0.0.1',
port: env.port,
path: '/health',
method: 'GET',
headers: {
'User-Agent': 'Dashback-HealthMonitor/1.0',
'Accept': 'application/json',
},
timeout: 10000,
},
(res) => {
let data = '';
res.on('data', (chunk) => {
data += chunk;
});
res.on('end', () => {
const durationMs = Math.round((performance.now() - start) * 100) / 100;
if (res.statusCode >= 200 && res.statusCode < 300) {
resolve({ success: true, durationMs, statusCode: res.statusCode, body: data });
} else {
resolve({ success: false, durationMs, statusCode: res.statusCode, body: data });
}
});
}
);
req.on('error', (err) => {
const durationMs = Math.round((performance.now() - start) * 100) / 100;
reject({ error: err, durationMs });
});
req.on('timeout', () => {
req.destroy(new Error('TCP connection or request timed out'));
});
req.end();
});
}
// MARK: returns latency series as [{ timestamp, value }] oldest first; range '3h' (default) = raw only, 'all' = raw + avg + max
export async function getLatencySeries({ range = '3h' } = {}) {
const redis = getRedisClient();
const parse = (members) =>
members.map((m) => {
const i = m.indexOf(':');
return { timestamp: Number(m.slice(0, i)), value: Number(m.slice(i + 1)) };
});
if (range === '3h') {
return { raw: parse(await redis.zrange(rawKey(), 0, -1)) };
}
const [raw, avg, max] = await Promise.all([
redis.zrange(rawKey(), 0, -1),
redis.zrange(avgKey(), 0, -1),
redis.zrange(maxKey(), 0, -1),
]);
return { raw: parse(raw), avg: parse(avg), max: parse(max) };
}
// MARK: stores one latency sample and trims samples older than 3 hours (round-robin window)
export async function recordLatency(durationMs, now = Date.now()) {
const redis = getRedisClient();
await redis
.multi()
.zadd(rawKey(), now, `${now}:${durationMs}`)
.zremrangebyscore(rawKey(), '-inf', now - RAW_RETENTION_MS)
.exec();
}
// MARK: computes avg/max over the last 4 hours, stores both with timestamp, purges aggregates older than 30 days
export async function aggregateLatency(now = Date.now()) {
const redis = getRedisClient();
const members = await redis.zrangebyscore(rawKey(), now - AGGREGATE_WINDOW_MS, '+inf');
const values = members
.map((m) => Number(m.slice(m.indexOf(':') + 1)))
.filter(Number.isFinite);
if (values.length > 0) {
const avg = Math.round((values.reduce((a, b) => a + b, 0) / values.length) * 100) / 100;
const max = Math.max(...values);
await redis
.multi()
.zadd(avgKey(), now, `${now}:${avg}`)
.zadd(maxKey(), now, `${now}:${max}`)
.exec();
healthLog.debug(`Aggregated ${values.length} samples: avg=${avg}ms max=${max}ms`);
} else {
healthLog.warn('No latency samples in the last 4h; skipping aggregate.');
}
const cutoff = now - AGGREGATE_RETENTION_MS;
await redis
.multi()
.zremrangebyscore(avgKey(), '-inf', cutoff)
.zremrangebyscore(maxKey(), '-inf', cutoff)
.exec();
}
// MARK: runs one selftest cycle and records the latency in Redis
async function executeHealthCheckCycle() {
try {
const result = await performHealthSelftest();
if (result.success) {
try {
await recordLatency(result.durationMs);
healthLog.debug(
`Health selftest passed in ${result.durationMs}ms; recorded in redis key "${rawKey()}"`
);
} catch (redisErr) {
healthLog.warn(`Failed to write latency to Redis: ${redisErr.message}`);
}
} else {
healthLog.warn(
`Health selftest returned HTTP ${result.statusCode} in ${result.durationMs}ms`
);
}
} catch (err) {
const msg = err?.error?.message || err?.message || String(err);
healthLog.warn(`Health selftest failed: ${msg}`);
}
}
// #endregion
// #region Service Lifecycle
// MARK: starts the periodic health check selftest service
export function startHealthMonitorService() {
if (isServiceRunning) return;
if (env.healthMonitor?.enabled === false) {
healthLog.info('Health monitor service is disabled by configuration.');
return;
}
isServiceRunning = true;
const intervalMs = env.healthMonitor?.intervalMs || 60_000;
// Run initial selftest after 1s warmup
scheduledTimer = setTimeout(() => {
scheduledTimer = null;
executeHealthCheckCycle().catch((err) => {
healthLog.error(`Initial health selftest error: ${err.message}`);
});
}, 1000);
// Schedule recurring selftest every minute
scheduledInterval = setInterval(() => {
executeHealthCheckCycle().catch((err) => {
healthLog.error(`Recurring health selftest error: ${err.message}`);
});
}, intervalMs);
// Aggregate avg/max and purge old aggregates every 30 minutes
aggregateInterval = setInterval(() => {
aggregateLatency().catch((err) => {
healthLog.warn(`Latency aggregation failed: ${err.message}`);
});
}, AGGREGATE_INTERVAL_MS);
healthLog.info(`Health monitor service started (selftest every ${Math.round(intervalMs / 1000)}s via TCP).`);
}
// MARK: stops the health check service and closes Redis client
export async function stopHealthMonitorService() {
isServiceRunning = false;
if (scheduledTimer) {
clearTimeout(scheduledTimer);
scheduledTimer = null;
}
if (scheduledInterval) {
clearInterval(scheduledInterval);
scheduledInterval = null;
}
if (aggregateInterval) {
clearInterval(aggregateInterval);
aggregateInterval = null;
}
if (redisClient) {
try {
await redisClient.quit();
} catch {
redisClient.disconnect();
} finally {
redisClient = null;
}
}
healthLog.info('Health monitor service stopped.');
}
// MARK: returns health monitor status
export function getHealthMonitorStatus() {
return {
enabled: env.healthMonitor?.enabled ?? true,
isRunning: isServiceRunning,
intervalMs: env.healthMonitor?.intervalMs || 60_000,
redisKey: env.redis.key,
redisHost: env.redis.host,
redisPort: env.redis.port,
};
}
// #endregion