test-running-exes

const child_process = require('child_process');
const util = require('util');
const fs = require('fs');

const readfile = util.promisify(fs.readFile); 
const readdir = util.promisify(fs.readdir);
const readlink = util.promisify(fs.readlink);

async function getRunningPids(): Promise<number[]> {
  const files = await readdir(`/proc`);
  const pids = files
    .map((file: string) => parseInt(file, 10))
    .filter((pid: number) => !isNaN(pid) && pid !== process.pid && pid !== 1);

  return pids;
}

interface ExeData {
  exe: string;
  pid: number;
}

async function getRunningExecutables(): Promise<ExeData[]> {
  const pids = await getRunningPids();
  const results = await Promise.all(
    pids.map(async (pid: number) => {
      try {
        const exe = await readlink(`/proc/${pid}/exe`);
        return {
          exe,
          pid,
        };
      } catch (ex) {
        // We might get EACCESS here, since we get the list of all process
        // and not all of them belongs to us.
        return null;
      }
    }),
  );

  return results.filter(result => result) as ExeData[];
}

// based on https://unix.stackexchange.com/questions/62154/when-was-a-process-started
async function getProcessUptimeInSeconds(pid: number) {
  const processStat = (await readfile(`/proc/${pid}/stat`)).toString();
  const systeUptime = (await readfile(`/proc/uptime`)).toString();

  const processStartTime = parseInt(processStat.split(' ')[21], 10) / 100;
  const uptime = parseInt(systeUptime.split(' ')[0], 10);

  return uptime - processStartTime;
}

describe('lambda health', () => {
  it('should run only one chrome', async () => {
    const exes = await getRunningExecutables();
    const secondsSinceStart = await getProcessUptimeInSeconds(exes[0].pid);

    expect(exes.length).toEqual(1);
    expect(exes[0].exe).toEqual('/tmp/chromium');
    expect(secondsSinceStart).toBeLessThan(60);
  });
});