app.js

require('dotenv').config()

const Promise = require('bluebird')
const WmiClient = require('wmi-client')

// let's boiler plate this to use later in the #map
const promisifiedClient = opts => Promise.promisifyAll(new WmiClient(opts))

/* wmi queries functions */
async function getWMI(wmi) {
  var osVersion = await wmi.queryAsync('SELECT SerialNumber,Caption,Version FROM Win32_OperatingSystem')
  var services = await wmi.queryAsync('select Caption, Status, Started, ProcessId, DisplayName, Name, PathName from Win32_Service')
  return { osVersion, services }
}

// @todo should be getting this from a config file or something
let servers = [
  { host:'10.0.10.95', name:'server1', username:process.env.ad_user, password:process.env.ad_pass },
  { host:'10.0.10.10', name:'server2', username:process.env.ad_user, password:process.env.ad_pass }
]

/* pass in the servers array so this function itself does not mutate. */
function populateWmiClients(servers) {
  // i was wrong, this is not async and doesn't make the connection
  // also ALWAYS RETURN THE THING
  return servers.map((server) => {
    const wmiOptions = {
      host: server.host,
      username: server.username,
      password: server.password,
    }
    // return a *new* object, not mutating the current ones in place
    return Object.assign({}, server, { wmi: promisifiedClient(wmiOptions) })
  })
}

/* this will be repeating every 5s */
// again, PASS IN THE THING YOU'RE REPLACING, don't mutate in the function
function getWmiData(servers) {
  // ALWAYS RETURN YOUR PROMISES
  return Promise.map(servers, s => getWMI(s.wmi).then(data => Object.assign({}, s, { data })))
}

function updateLoop(oldServers) => {
  return getWmiData(oldServers).then((newServers) => {
    // @TODO need a function to set these instead of replacing global in place
    servers = newServers
    // starting at 10 seconds, can always change it
    // Object.assign clones servers so you aren't mutating the elements in place
    return Promise.delay(10000).then(() => updateLoop(Object.assign({}, servers)))
  })
})

Promise.try(() => {
  return populateWmiClients(servers)
}).then((connectedServers) => {
  // connectedServers here is a *new array*, with the clients on each object.. now that we have them all, replace the global state
  // @TODO create a state setter function instead of just overwriting it here
  servers = connectedServers
}).then(() => {
  updateLoop(servers)
})