Files

46 lines
2.0 KiB
TypeScript

import { spawnSync } from 'node:child_process'
import { createHash } from 'node:crypto'
import { existsSync, readFileSync } from 'node:fs'
/**
* The git description of the checkout of dir now, a commit or a tag changing it without a restart; outside a
* checkout, or without git, the variable named fallbackVariable, which a container image sets, or "dev".
*/
export function gitVersion(dir: string, fallbackVariable: string) {
const described = spawnSync('git', ['describe', '--tags', '--always', '--dirty'], { cwd: dir, encoding: 'utf8' })
return described.status === 0 ? described.stdout.trim() : process.env[fallbackVariable] || 'dev'
}
/**
* Ctrl-C and SIGTERM, which watch mode sends on a restart, call close and end the process when it settles, or after 5
* seconds.
*/
export function exitOnSignals(close: () => Promise<unknown>) {
for (const signal of ['SIGINT', 'SIGTERM'] as const) {
process.on(signal, () => {
setTimeout(() => process.exit(0), 5000).unref()
void close().then(() => process.exit(0))
})
}
}
/**
* The JSON object of the file at path, and its version, the SHA-256 of the bytes. With missingAsEmpty a missing file
* reads as {}, whose version is that of "{}". A file that cannot be read, invalid JSON or another value than an
* object throws with the reason.
*/
export function readJsonObject(path: string, options: { missingAsEmpty: boolean }): { data: Record<string, unknown>; version: string } {
let bytes: Buffer
let data: unknown
try {
bytes = options.missingAsEmpty && !existsSync(path) ? Buffer.from('{}') : readFileSync(path)
data = JSON.parse(bytes.toString('utf8'))
} catch (error) {
throw new Error(`${path} cannot be read: ${(error as Error).message}`)
}
if (data === null || typeof data !== 'object' || Array.isArray(data)) {
throw new Error(`${path} must hold a JSON object`)
}
return { data: data as Record<string, unknown>, version: createHash('sha256').update(bytes).digest('hex') }
}