import _ from 'lodash';
import fetch from 'node-fetch';
import delay from 'delay';
import co from 'co';

export const pingServers = (servers) => co(function*() {
  let failedServers = {};
  for (const url of servers) {
    let failures = 0;
    for (const i of _.range(3)) {
      const response = yield fetch(url);
      if (!response.ok) failures++;
      yield delay(10000);
    }
    if (failures > 0) failedServers[url] = failures;
  }
  return failedServers;
})