bb97993755
- Add Prometheus metrics endpoints (GET /metrics) - Add health checks (GET /health, GET /ready) - Add OpenTelemetry SDK with automatic HTTP instrumentation - Expose update metrics for messages, AI calls, and errors
98 lines
2.9 KiB
TypeScript
98 lines
2.9 KiB
TypeScript
/**
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* HTTP handler for Prometheus metrics endpoint.
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*
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* Exposes metrics at GET /metrics in Prometheus text format.
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*/
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import type { IncomingMessage, ServerResponse } from 'node:http';
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import { getMetricsText, getMetricsContentType } from '../infra/metrics.js';
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/**
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* Handle GET /metrics requests for Prometheus scraping.
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*/
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export async function handleMetricsRequest(
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_req: IncomingMessage,
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res: ServerResponse,
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): Promise<void> {
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try {
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const metricsText = await getMetricsText();
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res.writeHead(200, {
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'Content-Type': getMetricsContentType(),
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'Cache-Control': 'no-cache, no-store, must-revalidate',
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});
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res.end(metricsText);
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} catch (error) {
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res.writeHead(500, { 'Content-Type': 'text/plain' });
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res.end('Error collecting metrics');
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}
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}
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/**
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* Handle GET /health liveness probe.
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* Always returns 200 if the server is responding.
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*/
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export function handleHealthRequest(
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_req: IncomingMessage,
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res: ServerResponse,
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): void {
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res.writeHead(200, { 'Content-Type': 'application/json' });
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res.end(JSON.stringify({
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status: 'ok',
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timestamp: new Date().toISOString(),
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}));
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}
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/**
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* Readiness check function type.
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* Returns true if the service is ready to accept traffic.
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*/
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export type ReadinessCheck = () => Promise<boolean> | boolean;
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/**
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* Create a readiness handler with custom checks.
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*
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* @param checks - Array of check functions that must all pass
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*/
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export function createReadinessHandler(
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checks: ReadinessCheck[] = [],
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): (req: IncomingMessage, res: ServerResponse) => Promise<void> {
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return async (_req: IncomingMessage, res: ServerResponse): Promise<void> => {
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try {
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const results = await Promise.all(checks.map((check) => check()));
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const isReady = results.every(Boolean);
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if (isReady) {
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res.writeHead(200, { 'Content-Type': 'application/json' });
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res.end(JSON.stringify({
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status: 'ready',
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timestamp: new Date().toISOString(),
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}));
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} else {
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res.writeHead(503, { 'Content-Type': 'application/json' });
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res.end(JSON.stringify({
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status: 'not_ready',
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timestamp: new Date().toISOString(),
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}));
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}
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} catch (error) {
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res.writeHead(503, { 'Content-Type': 'application/json' });
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res.end(JSON.stringify({
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status: 'error',
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timestamp: new Date().toISOString(),
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}));
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}
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};
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}
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/**
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* Simple readiness handler that always returns ready.
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* Use createReadinessHandler for custom checks.
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*/
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export async function handleReadyRequest(
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req: IncomingMessage,
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res: ServerResponse,
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): Promise<void> {
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const handler = createReadinessHandler([]);
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return handler(req, res);
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}
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