artsite/sync/sync-service.js

const utils = require('../libs/utils');
const path = require('path');
const MongoClient = require('mongoose').mongo.MongoClient;
const appConfig = require('../config/app');
const SyncSeq = require('./sync-seq');
const { format } = require('date-fns');

const remotedb = 'coloring_ol';  // 远端数据库
const localdb = 'artsite';  // 本地的数据库
/**
 * sync from remote
 */
async function run() {
  const localClient = await new MongoClient(appConfig.mongodbUrl).connect();
  const remoteClient = await new MongoClient(appConfig.syncUrl).connect();

  let remoteDB = remoteClient.db(remotedb);
  let localDB = localClient.db(localdb);

  console.log('Connect to remote mongodb ' + appConfig.syncUrl + ' success!');

  // 读取远程syncevent表
  const synceventTB = remoteDB.collection('syncevents');
  // get current local slave sync seq (use mongoose)
  let seq = -1;
  let seqDoc = await SyncSeq.findOne();
  if (seqDoc) seq = seqDoc.seq;
  else seqDoc = new SyncSeq({});

  let count, localtb, remotetb, localdoc, remotedoc;
  setTimeout(async function cycleRun() {
    try {
      let eventDocs = await synceventTB.find({ _id: { $gt: seq } }).limit(200).toArray() || [];
      count = 0;
      for (let i = 0; i < eventDocs.length; i++) {
        let eventDoc = eventDocs[i];
        // 只同步特定的几张表： arts， daily-arts， users， albums， translates
        if (eventDoc.tb == 'arts'
          || eventDoc.tb == 'daily-arts'
          || eventDoc.tb == 'users'
          || eventDoc.tb == 'albums'
          || eventDoc.tb == 'videostories'
          || eventDoc.tb == 'translates') {

          console.log(eventDoc);

          if (!eventDoc.db) eventDoc.db = remoteDbs[0];
          // 对应的表
          remotetb = remoteDB.collection(eventDoc.tb);
          localtb = localDB.collection(eventDoc.tb);
          if (remotetb && localtb) {
            if (eventDoc.op == 'remove') {
              await localtb.deleteOne({ _id: eventDoc.rid });
              console.log("sync remove : " + eventDoc.tb + " " + eventDoc.rid);
            } else if (eventDoc.op == 'save') {
              remotedoc = await remotetb.findOne({ _id: eventDoc.rid });
              localdoc = await localtb.findOne({ _id: eventDoc.rid });
              if (!remotedoc) {
                console.log("remote doc not found, may be deleted, skip: " + eventDoc.tb + " " + eventDoc.rid);
              } else if (!localdoc) {
                console.log("sync add :" + eventDoc.tb + " " + eventDoc.rid);
                try {
                  await localtb.insertOne(remotedoc);
                } catch (e) {
                  console.error(e);
                }
              } else {
                console.log("sync update :" + eventDoc.tb + " " + eventDoc.rid);
                if (eventDoc.tb == 'arts') { // art 表需保留新的title,desc,copy 这几个字段，避免覆盖
                  remotedoc.title = localdoc.title;
                  remotedoc.desc = localdoc.desc;
                  remotedoc.seoTitle = localdoc.seoTitle;
                  remotedoc.seoDescription = localdoc.seoDescription;
                  remotedoc.open = localdoc.open;
                } else if (eventDoc.tb == 'albums' || eventDoc.tb == 'videostories') { // albums 和 videostories 表需保留新增的seoTitle，seoDescription字段，避免覆盖
                  remotedoc.seoTitle = localdoc.seoTitle;
                  remotedoc.seoDescription = localdoc.seoDescription;
                }
                await localtb.replaceOne({ _id: eventDoc.rid }, remotedoc);
              }
            }
          }
        }

        seq = eventDoc._id;
        seqDoc.seq = seq;
        count++;
      }

      await seqDoc.save();

      console.log(`${format(new Date(), 'yyyy-MM-dd HH:mm')} sync event length: ${eventDocs.length}, precessed: ${count}`);

    } catch (err) {
      console.error(err);
    }

    if (count > 0) setTimeout(cycleRun, 0);
    // else setTimeout(run, delay);

  }, 0);

}


module.exports = {
  run
}


if (require.main == module) {
  run().catch(console.error);
}