| 1 | #!/usr/bin/env node |
| 2 | // Runs the services' cron triggers in a self-hosted g1t. `wrangler dev` |
| 3 | // (workerd) never fires a Worker's `scheduled` handler on its own, so this |
| 4 | // does: once a minute it asks Wrangler's local API to run the handler of |
| 5 | // each service whose cron matches the time (UTC), the same handler hosted |
| 6 | // g1t's Cron Triggers run. |
| 7 | // |
| 8 | // Which services, and their crons, are in schedules.json, written by |
| 9 | // configs.mjs from each service's wrangler.jsonc (`triggers.crons`), for |
| 10 | // the services whose crons are safe to run here (SELF_HOST_CRONS there). |
| 11 | // Wrangler's local API answers only requests addressed to localhost, so |
| 12 | // this runs inside the g1t container, beside it (start.sh). |
| 13 | // |
| 14 | // Usage: node scheduler.mjs <schedules.json> [base URL, default http://127.0.0.1:8787] |
| 15 | |
| 16 | import { readFileSync } from "node:fs"; |
| 17 | |
| 18 | const FIELDS = [ |
| 19 | { min: 0, max: 59 }, // minute |
| 20 | { min: 0, max: 23 }, // hour |
| 21 | { min: 1, max: 31 }, // day of the month |
| 22 | { min: 1, max: 12 }, // month |
| 23 | { min: 0, max: 7 }, // day of the week, 0 and 7 both Sunday |
| 24 | ]; |
| 25 | |
| 26 | /** The values one cron field allows, or null when it is malformed. */ |
| 27 | export function fieldValues(text, { min, max }) { |
| 28 | const values = new Set(); |
| 29 | for (const part of text.split(",")) { |
| 30 | const [range, stepText] = part.split("/"); |
| 31 | const step = stepText === undefined ? 1 : Number(stepText); |
| 32 | if (!Number.isInteger(step) || step < 1) return null; |
| 33 | let from; |
| 34 | let to; |
| 35 | if (range === "*") { |
| 36 | [from, to] = [min, max]; |
| 37 | } else if (range.includes("-")) { |
| 38 | [from, to] = range.split("-").map(Number); |
| 39 | } else { |
| 40 | from = Number(range); |
| 41 | to = stepText === undefined ? from : max; |
| 42 | } |
| 43 | if (!Number.isInteger(from) || !Number.isInteger(to) || from < min || to > max || from > to) return null; |
| 44 | for (let value = from; value <= to; value += step) values.add(value); |
| 45 | } |
| 46 | return values; |
| 47 | } |
| 48 | |
| 49 | /** Whether a five-field cron expression matches `date` (UTC, to the minute). */ |
| 50 | export function matches(cron, date) { |
| 51 | const fields = cron.trim().split(/\s+/); |
| 52 | if (fields.length !== 5) return false; |
| 53 | const sets = fields.map((field, i) => fieldValues(field, FIELDS[i])); |
| 54 | if (sets.some((set) => set === null)) return false; |
| 55 | const [minutes, hours, days, months, weekdays] = sets; |
| 56 | const weekday = date.getUTCDay(); |
| 57 | const dayMatches = days.has(date.getUTCDate()); |
| 58 | const weekdayMatches = weekdays.has(weekday) || (weekday === 0 && weekdays.has(7)); |
| 59 | // As cron does: when both day fields are restricted, either may match. |
| 60 | const day = |
| 61 | fields[2] !== "*" && fields[4] !== "*" ? dayMatches || weekdayMatches : dayMatches && weekdayMatches; |
| 62 | return minutes.has(date.getUTCMinutes()) && hours.has(date.getUTCHours()) && months.has(date.getUTCMonth() + 1) && day; |
| 63 | } |
| 64 | |
| 65 | /** The handlers due at `date`: `{ worker, cron }` for each cron that matches. */ |
| 66 | export function due(schedules, date) { |
| 67 | return schedules.flatMap(({ worker, crons }) => crons.filter((cron) => matches(cron, date)).map((cron) => ({ worker, cron }))); |
| 68 | } |
| 69 | |
| 70 | async function run(base, { worker, cron }) { |
| 71 | try { |
| 72 | const answer = await fetch(`${base}/cdn-cgi/local/explorer/api/local/scheduled?worker=${encodeURIComponent(worker)}`, { |
| 73 | method: "POST", |
| 74 | headers: { "content-type": "application/json" }, |
| 75 | body: JSON.stringify({ cron }), |
| 76 | }); |
| 77 | const body = await answer.json().catch(() => ({})); |
| 78 | if (!answer.ok || !body.success || body.result?.outcome !== "ok") { |
| 79 | console.error(`scheduler: ${worker} (${cron}): ${answer.status} ${JSON.stringify(body.errors ?? body.result ?? body)}`); |
| 80 | } |
| 81 | } catch (error) { |
| 82 | console.error(`scheduler: ${worker} (${cron}) could not be run: ${error.message}`); |
| 83 | } |
| 84 | } |
| 85 | |
| 86 | if (process.argv[1]?.replaceAll("\\", "/").endsWith("deploy/self-host/scheduler.mjs")) { |
| 87 | const schedules = JSON.parse(readFileSync(process.argv[2], "utf8")); |
| 88 | const base = (process.argv[3] ?? "http://127.0.0.1:8787").replace(/\/$/, ""); |
| 89 | console.log(`scheduler: ${schedules.map((s) => `${s.worker} ${s.crons.join(", ")}`).join("; ")}`); |
| 90 | const tick = () => { |
| 91 | const now = new Date(); |
| 92 | for (const job of due(schedules, now)) run(base, job); |
| 93 | // The next whole minute, a second in. |
| 94 | setTimeout(tick, 60_000 - (now.getTime() % 60_000) + 1_000); |
| 95 | }; |
| 96 | setTimeout(tick, 60_000 - (Date.now() % 60_000) + 1_000); |
| 97 | } |