[Exporting Data from Google Cloud Datastore](https://cloud.google.com/datastore/docs/export-import-entities#rest_ seems easy:
From the Commandline:
sh```
gcloud datastore export gs://exampleBucket/backupdir
Or in node.js:
js```
const datastore = new Datastore()
datastore.export({outputUrlPrefix: 'gs://exampleBucket/backupdir'});
So why do you need a library for that? Because it is in the details!
For one thing the code above contains an export containing all kinds can not be loaded into BigQuery: Data exported without specifying an entity filter cannot be loaded into BigQuery."
So you need a list of all Kinds in the Datastore. But there are Limits on entity filters: "Each request is limited to 100 entity filter combinations, where each combination of filtered kind and namespace counts as a separate filter towards this limit." (It was 50 e few years before.)
And there is an other limit: "The managed export and import service limits the number of concurrent exports and imports to 50 and allows a maximum of 20 export and import requests per minute for a project."
So if you have a lot of entities you have to do some slicing and dicing.
CLI Usage
Command line usage is simple. You have to provide the projectId of the datastore and a bucket name. Both have to be in the same region.
% yarn ts-node src/bin/backup.ts --help
usage: backup.ts [-h] [-v] [-d BACKUPDIR] [-n BACKUPNAME] [-s NAMESPACE] projectId bucket
Backup Datastore.
positional arguments:
projectId Datastore project ID
bucket GCS bucket to store backup
optional arguments:
-h, --help show this help message and exit
-d BACKUPDIR, --backupDir BACKUPDIR
prefix/dir within bucket
-n BACKUPNAME, --backupName BACKUPNAME
name of backup (default: autogenerated)
-s NAMESPACE, --namespace NAMESPACE
datastore namespace
Please provide `GOOGLE_APPLICATION_CREDENTIALS` via the Environment!
% export GOOGLE_APPLICATION_CREDENTIALS=~/sampleproj-b0a74af0545e.json
% yarn ts-node src/bin/backup.ts sampleproj samplebucket-tmp
ℹ backup to gs://hudora-tmp/bak/20211221T212651-sampleproj
ℹ Dumping datastore sampleproj
✔ 2 Kinds
2 kinds ℹ Dumping NumberingAncestor, NumberingItem
2 kinds ℹ Dumping to gs://samplebucket-tmp/bak/20211221T212651-sampleproj-0
2 kinds ✔ Dumping finished 27150 records (4.04 MB) in 51s
2 kinds ✔ written gs://samplebucket-tmp/bak/20211221T212651-sampleproj-0/20211221T212651-sampleproj-0.overall_export_metadata
✨ Done in 54.16s.
This generates a single folder structure under gs://samplebucket-tmp/bak/20211221T212651-sampleproj-0
. For projects with more than 100 entities more folders will be generated.
There is one subfolder per kind containing the Entities encoded in LevelDB Format.
Programmatic Usage
import { Datastore } from '@google-cloud/datastore';
import { dumpAllKinds } from '../lib/datastore-backup';
await dumpAllKinds(new Datastore({ projectId: 'sampleproj' }), 'samplebucket-tmp')
See also