feat: implement the action in typescript

src/setup.ts

@@ -0,0 +1,126 @@
+import { createHash, randomUUID } from 'node:crypto'
+import { createWriteStream } from 'node:fs'
+import { mkdir } from 'node:fs/promises'
+import { join } from 'node:path'
+import { env, stdout } from 'node:process'
+import { Readable } from 'node:stream'
+
+import { addPath, debug, getInput, saveState, setFailed, warning } from '@actions/core'
+import { fetch } from 'undici'
+
+export async function installKubectl() {
+	debug('Running kubectl-action installKubectl()')
+
+	if (env.RUNNER_TEMP === undefined) {
+		setFailed('$RUNNER_TEMP is not defined')
+		return
+	}
+
+	const input = getInput('kubectl-version', {
+		required: false,
+		trimWhitespace: true
+	})
+
+	const version = input || await fetchLatestVersion()
+
+	if (!version?.startsWith('v')) {
+		setFailed('Unable to determine the `kubectl` version to install')
+		return
+	}
+
+	console.log(`Installing kubectl version ${version}`)
+
+	const kubectl = await downloadKubectl(version)
+
+	if (!kubectl) {
+		return
+	}
+
+	const path = join(env.RUNNER_TEMP, randomUUID())
+	await mkdir(path, { recursive: true })
+	saveState('kubectl-path', path)
+
+	const stream = createWriteStream(join(path, 'kubectl'))
+
+	kubectl.pipe(stream)
+
+	console.log(`Installing kubectl to ${path}`)
+	await new Promise<void>((resolve, reject) => {
+		stream.on('finish', resolve)
+		stream.on('error', reject)
+	})
+
+	addPath(path)
+}
+
+// Fetches the latest kubectl version from the Kubernetes release server
+async function fetchLatestVersion() {
+	const response = await fetch('https://dl.k8s.io/release/stable.txt')
+	if (!response.ok) {
+		setFailed(`Failed to fetch latest kubectl version with status ${response.status}`)
+		return
+	}
+
+	const version = await response.text()
+	return version.trim()
+}
+
+// Downloads the kubectl binary from the Kubernetes release server
+// Also runs a checksum verification on the downloaded binary
+async function downloadKubectl(version: string) {
+	const url = `https://dl.k8s.io/release/${version}/bin/linux/amd64/kubectl`
+	const hashUrl = `${url}.sha256`
+
+	console.log(`Downloading kubectl (${url})`)
+
+	const hashResponse = await fetch(hashUrl)
+	if (!hashResponse.ok) {
+		warning(`Skipping checksum verification for kubectl ${version}`)
+	}
+
+	const hash = hashResponse.ok ? await hashResponse.text() : ''
+
+	const response = await fetch(url)
+	if (!response.ok || !response.body) {
+		setFailed(`Failed to download kubectl with status ${response.status}`)
+		return
+	}
+
+	const hashStream = createHash('sha256')
+	const body = Readable.fromWeb(response.body)
+	const size = Number(response.headers.get('content-length'))
+
+	return new Promise<Readable | void>((resolve, reject) => {
+		let downloaded = 0
+		let progressed = 0
+
+		body.on('data', (chunk: Buffer) => {
+			hashStream.update(chunk)
+			downloaded += chunk.length
+
+			if (Math.floor((downloaded / size) * 80) > progressed) {
+				stdout.clearLine(0)
+				stdout.cursorTo(0)
+
+				progressed++
+				stdout.write(`[${'='.repeat(progressed)}>${' '.repeat(80 - progressed)}]`)
+			}
+		})
+
+		body.on('end', () => {
+			stdout.clearLine(0)
+			stdout.cursorTo(0)
+			console.log(`[${'='.repeat(80)}]`)
+
+			const hashSum = hashStream.digest('hex')
+			if (hashResponse.ok && hashSum !== hash) {
+				setFailed(`Checksum verification failed for kubectl ${version}`)
+				resolve()
+			}
+
+			resolve(body)
+		})
+
+		body.on('error', reject)
+	})
+}