data-service-sdam_viz.js

const log = require ('ololog').configure ({ 
  locate: false
});
const { green, yellow, red, cyan, magenta, lightGray, darkGray, inverse, bgLightCyan, underline, dim } = require ('ansicolor')
const stringify = require ('string.ify')
const arrayStrictEqual = require('strict-array-equals');
 
function diff(lhs, rhs, fields, comparator) {
  return fields.reduce((diff, field) => {
    if (lhs[field] == null || rhs[field] == null) {
      return diff;
    }
 
    if (!comparator(lhs[field], rhs[field])) {
      diff.push(
        `${field}: ${yellow(`[${lhs[field]}]`)} => ${green(`[${rhs[field]}]`)}`
      );
    }
 
    return diff;
  }, []);
}
 
function serverDescriptionDiff(lhs, rhs) {
  const objectIdFields = ['electionId'];
  const arrayFields = ['hosts', 'tags'];
  const simpleFields = [
    'type',
    'minWireVersion',
    'me',
    'setName',
    'setVersion',
    'electionId',
    'primary',
    'logicalSessionTimeoutMinutes'
  ];
 
  return diff(lhs, rhs, simpleFields, (x, y) => x === y)
    .concat(diff(lhs, rhs, arrayFields, (x, y) => arrayStrictEqual(x, y)))
    .concat(diff(lhs, rhs, objectIdFields, (x, y) => x.equals(y)));
}
 
function topologyDescriptionDiff(lhs, rhs) {
  const simpleFields = [
    'type',
    'setName',
    'maxSetVersion',
    'stale',
    'compatible',
    'compatibilityError',
    'logicalSessionTimeoutMinutes',
    'error',
    'commonWireVersion'
  ];
 
  return diff(lhs, rhs, simpleFields, (x, y) => x === y);
}
class DataService{
setupListeners(client) {
    this.client = client;
    log(`${underline('Connecting')}`);
    log(`${client.s.url}`);
    log(client.s.options);

    if (client) {
      client.on('serverDescriptionChanged', event => {
        const diff = serverDescriptionDiff(event.previousDescription, event.newDescription);
        log(`${cyan('server')} [${event.address}] changed:`);
        diff.map(line => log('  ' + line));

        this.emit('serverDescriptionChanged', event);
      });
      client.on('serverOpening', event => {
        log(
          `${cyan('server')} [${event.address}] ${underline('opening')} in topology#${
            event.topologyId
          }`
        );
        this.emit('serverOpening', event);
      });

      client.on('serverClosed', event => {
        log(
          `${cyan('server')} [${event.address}] ${underline('closed')} in topology#${
            event.topologyId
          }`
        );
        this.emit('serverClosed', event);
      });

      client.on('topologyOpening', event => {
        log(`${magenta('topology')} adding topology#${event.topologyId}`);
        this.emit('topologyOpening', event);
      });

      client.on('topologyClosed', event => {
        log(`${magenta('topology')} removing topology#${event.topologyId}`);
        this.emit('topologyClosed', event);
      });

      client.on('topologyDescriptionChanged', event => {
        client.isWritable = this._isWritable(event);
        client.isMongos = this._isMongos(event);
        const diff = topologyDescriptionDiff(event.previousDescription, event.newDescription);
        if (diff.length > 0) {
          log(`${magenta('topology')} [topology#${event.topologyId}] changed:`);
          diff.map(line => log('  ' + line));
        }

        this.emit('topologyDescriptionChanged', event);
      });

      client.on('serverHeartbeatSucceeded', event => {
        log(
          `${darkGray('heartbeat')} ${green('succeeded')} host: '${
            event.connectionId
          }' ${lightGray(`(${event.duration} ms)`)}`
        )

        this.emit('serverHeartbeatSucceeded', event);
      });

      client.on('serverHeartbeatFailed', event => {
        debug('serverHeartbeatFailed');
        log(
          `${darkGray('heartbeat')} ${red('failed')} host: '${
            event.connectionId
          }' ${lightGray(`(${event.duration} ms)`)}`
        )
        this.emit('serverHeartbeatFailed', event);
      });
    }
  }
  }