Function fetch

telemetry-worker/src/index.ts:188–259

(request, env, ctx)

export default {
  async fetch(request, env, ctx): Promise<Response> {
    try {
      const url = new URL(request.url);

      if (request.method === 'GET' && url.pathname === '/') {
        return new Response(INFO_TEXT, { headers: { 'content-type': 'text/plain; charset=utf-8' } });
      }
      if (url.pathname !== '/v1/events') {
        return new Response('not found\n', { status: 404 });
      }
      if (request.method !== 'POST') {
        return new Response('method not allowed\n', { status: 405, headers: { allow: 'POST' } });
      }

      const contentLength = Number(request.headers.get('content-length'));
      if (!Number.isFinite(contentLength) || contentLength <= 0) {
        return new Response('length required\n', { status: 411 });
      }
      if (contentLength > MAX_BODY_BYTES) {
        return new Response('payload too large\n', { status: 413 });
      }

      let body: JsonObject;
      try {
        const text = await request.text();
        if (text.length > MAX_BODY_BYTES) return new Response('payload too large\n', { status: 413 });
        const parsed: unknown = JSON.parse(text);
        if (typeof parsed !== 'object' || parsed === null || Array.isArray(parsed)) {
          return new Response('bad request\n', { status: 400 });
        }
        body = parsed as JsonObject;
      } catch {
        return new Response('bad request\n', { status: 400 });
      }

      const machineId = body.machine_id;
      if (typeof machineId !== 'string' || !UUID_RE.test(machineId)) {
        return new Response('bad request\n', { status: 400 });
      }

      // Best-effort rate limit; fails open — losing a data point beats losing availability.
      try {
        const { success } = await env.MACHINE_RATE_LIMITER.limit({ key: machineId });
        if (!success) return new Response('rate limited\n', { status: 429 });
      } catch (err) {
        console.error(JSON.stringify({ msg: 'rate limiter unavailable', err: String(err) }));
      }

      const common: JsonObject = {};
      for (const [key, sanitize] of Object.entries(ENVELOPE_PROPS)) {
        const val = sanitize(body[key]);
        if (val !== undefined) common[key] = val;
      }

      const rawEvents = Array.isArray(body.events) ? body.events.slice(0, MAX_EVENTS_PER_BATCH) : [];
      const batch: PostHogEvent[] = [];
      for (const raw of rawEvents) {
        const sanitized = sanitizeEvent(raw, machineId, common);