Cloud datastore access to appengine python with out Managed vm or Compute engine.

[sasivarunan]

All the demos and guides shows how to access cloud datastore from python on GCE or from local machine, but is it possible to access cloud datastore from python hosted on a GAE ?

from gcloud import datastore
import os
import webapp2

# dataset = datastore.get_dataset(
#     'appid',
#     'xxx@developer.gserviceaccount.com',
#     os.path.abspath("appid.p12"))
#
# entity = dataset.entity('People')
# entity['name'] = 'helloworld'
# entity['age'] = 25
# entity.save()
# print 'Hello, world!'
class MainPage(webapp2.RequestHandler):
    def get(self):
        dataset = datastore.get_dataset(
            'appid',
            'xxxx@developer.gserviceaccount.com',
            os.path.abspath("appid.p12"))

        entity = dataset.entity('People')
        entity['name'] = 'helloworld'
        entity['age'] = 25
        entity.save()
        self.response.out.write('Hello')


application = webapp2.WSGIApplication([
    ('/', MainPage)
], debug=True)

I don't seem to get this working. like https://cloud.google.com/appengine/docs/python/gettingstartedpython27/helloworld

If anyone has this working on appengine please share. Thanks

[dhermes]

@sasivarunan It is on our todo list, but you can use the datastore directly using ndb.

Is there a reason you can't or don't want to do this?

The most difficult part for you will be auth, but IIRC you can get an access token for the service account associated with you app. (It's possible in Go, for example, which means the underlying RPC is available in Python.)

I've gotta run but will look into this more. You should check out how to create a Credentials object from the oauth2client library with only an access token.

[sasivarunan]

I guess with ndb i can only access only native datastore associated with my app id not a cloud datastore

[dhermes]

I see. It's not a typical use case. Do you actually need to access more than one datastore instance or do you instead need non-App Engine clients to access the same one?

[sasivarunan]

need to access more than one datastore instance
thanks

[dhermes]

Update, you can get an access token for the application via the app_identity API. Luckily the oauth2client.appengine.AppAssertionCredentials class supports this.

You can use these credentials with this library via the following:

from gcloud.datastore import SCOPE
from gcloud.datastore.connection import Connection

from oauth2client.appengine import AppAssertionCredentials

app_credentials = AppAssertionCredentials(SCOPE)
connection = Connection(credentials=app_credentials)

I have not tested this yet, so am not 100% sure (will try to later).

Also, I am not closing this bug since we'd like to support this.

[dhermes]

I'm closing out. @sasivarunan feel free to follow along in #335 where I'll be addressing this and much more shortly.