const { ReadPreference, ObjectId } = require('mongodb') const { db, waitForDb } = require('../../app/src/infrastructure/mongodb') const BATCH_SIZE = parseInt(process.env.BATCH_SIZE, 10) || 1000 let BATCH_LAST_ID if (process.env.BATCH_LAST_ID) { BATCH_LAST_ID = ObjectId(process.env.BATCH_LAST_ID) } async function getNextBatch(collection, query, maxId, projection) { maxId = maxId || BATCH_LAST_ID if (maxId) { query['_id'] = { $gt: maxId } } const entries = await collection .find(query) .project(projection) .sort({ _id: 1 }) .limit(BATCH_SIZE) .setReadPreference(ReadPreference.SECONDARY) .toArray() return entries } async function performUpdate(collection, nextBatch, update) { return collection.updateMany( { _id: { $in: nextBatch.map(entry => entry._id) } }, update ) } async function batchedUpdate(collectionName, query, update, projection) { await waitForDb() const collection = db[collectionName] projection = projection || { _id: 1 } let nextBatch let updated = 0 let maxId while ( (nextBatch = await getNextBatch(collection, query, maxId, projection)) .length ) { maxId = nextBatch[nextBatch.length - 1]._id updated += nextBatch.length console.log(JSON.stringify(nextBatch)) if (typeof update === 'function') { await update(collection, nextBatch) } else { await performUpdate(collection, nextBatch, update) } } return updated } function batchedUpdateWithResultHandling(collection, query, update) { batchedUpdate(collection, query, update) .then(updated => { console.error({ updated }) process.exit(0) }) .catch(error => { console.error({ error }) process.exit(1) }) } module.exports = { getNextBatch, batchedUpdate, batchedUpdateWithResultHandling }