a script to sync mongodb indexes

sync-mongo-db-indexes.js

require("dotenv").config();
const mongoClient = require("mongodb").MongoClient;

const MONGO_DB_SRC =
  process.env.MONGO_DB_SRC || "mongodb://localhost:27017/db1";
const MONGO_DB_DEST =
  process.env.MONGO_DB_DEST || "mongodb://localhost:27017/db2";

const syncIndexes = async () => {
  try {
    console.log("Fetching indexes from source ...");
    const client = await mongoClient.connect(MONGO_DB_SRC, {
      useNewUrlParser: true,
      useUnifiedTopology: true,
    });
    const db = client.db();
    const collections = await db.listCollections().toArray();
    const collectionNames = collections.map((collection) => collection.name);
    let results = await Promise.allSettled(
      collectionNames.map(async (collectionName) => {
        let indexList = [];
        let indexes = await db.collection(collectionName).indexes();
        indexes.forEach((index) => {
          delete index.v;
          delete index.ns;
          let key = index.key;
          delete index.key;
          let options = {};
          for (let opt in index) {
            options[opt] = index[opt];
          }
          indexList.push({ key: key, options: options });
        });
        return {
          collectionName: collectionName,
          indexes: indexList,
        };
      })
    );
    results
      .filter((result) => result.status === "rejected")
      .forEach((result) => {
        console.error(result.reason.message);
        console.log("-".repeat(50));
      });
    results = results.filter((result) => result.status === "fulfilled");
    let indexes = results.map((result) => result.value);
    console.log("Indexes fetched successfully.");
    console.log("list of indexes ");
    indexes.map((index) => console.log(JSON.stringify(index)));
    console.log("Syncing indexes to destination ...");
    const clientDest = await mongoClient.connect(MONGO_DB_DEST, {
      useNewUrlParser: true,
      useUnifiedTopology: true,
    });
    const dbDest = clientDest.db();
    await Promise.allSettled(
      indexes.map(async (index) => {
        let indexList = index.indexes || [];

        return await Promise.allSettled(
          indexList.map(async (indexObj) => {
            try {
              console.log(
                "Syncing index",
                JSON.stringify(indexObj),
                "for collection",
                index.collectionName,
                "..."
              );
              return await dbDest
                .collection(index.collectionName)
                .createIndex(indexObj.key, indexObj.options);
            } catch (error) {
              console.log(error);
            }
          })
        );
      })
    );
    console.log("Indexes synced successfully");
    process.exit(0);
  } catch (err) {
    console.log(err);
    process.exit(1);
  }
};

const main = async () => {
  await syncIndexes();
};

main();