How to retrieve the complete key from the returned object of an ancestor query in google datastore?

Question

I am using ancestor query to retrieve the entity from google datastore using nodejs

query = datastore.createQuery(entity).hasAncestor(key)

where the key is

key = datastore.key([kind_name_of_parent, id_of_parent])

I am able to retrieve the objects but i would like to get the complete key of the retrieved object, whereas the returned array only contains the returned objects and the endCursor.

How can i get the complete key? or, can i get the complete key from the endCursor?

An example for my query result is:

[{ modTS: 1481006473081, modLoc: null, modUid: 0, createTS: 1481006473081 } ], { moreResults: 'NO_MORE_RESULTS', endCursor: 'CloSVGoTc350ZXN0cHJvamVjdC0zN2ZiNnI9CxIEdXNlchiAgID409OICgw‌​LEgRzaW1zGICAgICAgIA‌​KDAsSDmNsaWVudFNldHR‌​wsdrfGICAgICA5NEKDBg‌​AIAA=' } ]

Answer 1

Since datastore client v0.42.2 the key is now referred using a Symbol on the datastore client datastoreClient.KEY.

Run this on the CLI, if it doesn't work the first time run it again (first time might fail because of 'eventual consistency').

'use strict';

const Datastore = require('@google-cloud/datastore'),
    projectId = 'your-project-id',
    datastore = Datastore({
        projectId: projectId
    }),
    pkind = 'Foo',
    pname = 'foo',
    kind = 'Bar',
    name = 'bar',
    parentKey = datastore.key([pkind, pname ]),
    entityKey = datastore.key([pkind, pname, kind, name]),
    entity = {
        key: entityKey,
        data: {
            propa: 'valuea'
        }
    },
    query = datastore.createQuery().hasAncestor(parentKey).limit(5);

let complete = false;

datastore.save(entity).then(() => {
    datastore.runQuery(query).then((res) => {
        try {
            console.log('parent key ', res[0][0][datastore.KEY].parent);
        } finally {
            complete = true;
        }
    });

});

function waitUntilComplete() {
    if (!complete)
        setTimeout(waitUntilComplete, 1000);
}

waitUntilComplete();

Answer 2

The latest update to the datastore SDK has changed the way keys are accessed in an entity.

Earlier the entity had a key called key which had a complete JSON object with information of the key.

After the update, the key is now referred using Symbols, a new ES6 datatype.

The key will be referenced using entity[datastoreClient.KEY] assuming datastoreClient is correctly authenticated/initialised object of the datasotore SDK.

Answer 3

The keys were retrieved by: res[0][0][datastore.KEY]