lens/build/download_kubectl.ts

import packageInfo from "../package.json";
import fs from "fs";
import request from "request";
import md5File from "md5-file";
import requestPromise from "request-promise-native";
import { ensureDir, pathExists } from "fs-extra";
import path from "path";

class KubectlDownloader {
  public kubectlVersion: string;
  protected url: string;
  protected path: string;
  protected dirname: string;

  constructor(clusterVersion: string, platform: string, arch: string, target: string) {
    this.kubectlVersion = clusterVersion;
    const binaryName = platform === "windows" ? "kubectl.exe" : "kubectl";
    this.url = `https://storage.googleapis.com/kubernetes-release/release/v${this.kubectlVersion}/bin/${platform}/${arch}/${binaryName}`;
    this.dirname = path.dirname(target);
    this.path = target;
  }

  protected async urlEtag() {
    const response = await requestPromise({
      method: "HEAD",
      uri: this.url,
      resolveWithFullResponse: true
    }).catch((error) => { console.log(error); });

    if (response.headers["etag"]) {
      return response.headers["etag"].replace(/"/g, "");
    }
    return "";
  }

  public async checkBinary() {
    const exists = await pathExists(this.path);
    if (exists) {
      const hash = md5File.sync(this.path);
      const etag = await this.urlEtag();
      if(hash == etag) {
        console.log("Kubectl md5sum matches the remote etag");
        return true;
      }

      console.log("Kubectl md5sum " + hash + " does not match the remote etag " + etag + ", unlinking and downloading again");
      await fs.promises.unlink(this.path);
    }

    return false;
  }

  public async downloadKubectl() {
    const exists = await this.checkBinary();
    if(exists) {
      console.log("Already exists and is valid");
      return;
    }
    await ensureDir(path.dirname(this.path), 0o755);

    const file = fs.createWriteStream(this.path);
    console.log(`Downloading kubectl ${this.kubectlVersion} from ${this.url} to ${this.path}`);
    const requestOpts: request.UriOptions & request.CoreOptions = {
      uri: this.url,
      gzip: true
    };
    const stream = request(requestOpts);

    stream.on("complete", () => {
      console.log("kubectl binary download finished");
      // eslint-disable-next-line @typescript-eslint/no-empty-function
      file.end(() => {});
    });

    stream.on("error", (error) => {
      console.log(error);
      // eslint-disable-next-line @typescript-eslint/no-empty-function
      fs.unlink(this.path, () => {});
      throw(error);
    });
    return new Promise((resolve, reject) => {
      file.on("close", () => {
        console.log("kubectl binary download closed");
        fs.chmod(this.path, 0o755, (err) => {
          if (err) reject(err);
        });
        resolve();
      });
      stream.pipe(file);
    });
  }
}

const downloadVersion = packageInfo.config.bundledKubectlVersion;
const baseDir = path.join(process.env.INIT_CWD, "binaries", "client");
const downloads = [
  { platform: "linux", arch: "amd64", target: path.join(baseDir, "linux", "x64", "kubectl") },
  { platform: "darwin", arch: "amd64", target: path.join(baseDir, "darwin", "x64", "kubectl") },
  { platform: "windows", arch: "amd64", target: path.join(baseDir, "windows", "x64", "kubectl.exe") },
  { platform: "windows", arch: "386", target: path.join(baseDir, "windows", "ia32", "kubectl.exe") }
];

downloads.forEach((dlOpts) => {
  console.log(dlOpts);
  const downloader = new KubectlDownloader(downloadVersion, dlOpts.platform, dlOpts.arch, dlOpts.target);
  console.log("Downloading: " + JSON.stringify(dlOpts));
  downloader.downloadKubectl().then(() => downloader.checkBinary().then(() => console.log("Download complete")));
});