Cloud Functions: How to copy Firestore Collection to a new document?
I wrote a small nodejs snippet for this.
const firebaseAdmin = require('firebase-admin');
const serviceAccount = '../../firebase-service-account-key.json';
const firebaseUrl = 'https://my-app.firebaseio.com';
firebaseAdmin.initializeApp({
credential: firebaseAdmin.credential.cert(require(serviceAccount)),
databaseURL: firebaseUrl
});
const firestore = firebaseAdmin.firestore();
async function copyCollection(srcCollectionName, destCollectionName) {
const documents = await firestore.collection(srcCollectionName).get();
let writeBatch = firebaseAdmin.firestore().batch();
const destCollection = firestore.collection(destCollectionName);
let i = 0;
for (const doc of documents.docs) {
writeBatch.set(destCollection.doc(doc.id), doc.data());
i++;
if (i > 400) { // write batch only allows maximum 500 writes per batch
i = 0;
console.log('Intermediate committing of batch operation');
await writeBatch.commit();
writeBatch = firebaseAdmin.firestore().batch();
}
}
if (i > 0) {
console.log('Firebase batch operation completed. Doing final committing of batch operation.');
await writeBatch.commit();
} else {
console.log('Firebase batch operation completed.');
}
}
copyCollection('customers', 'customers_backup').then(() => console.log('copy complete')).catch(error => console.log('copy failed. ' + error));
Currently, no. Looping through each document using Cloud Functions and then setting a new document to a different collection with the specified data is the only way to do this. Perhaps this would make a good feature request.
How many documents are we talking about? For something like 10,000 it should only take a few minutes, tops.