IssueTracker

If access to different app-engine accounts is not possible, at least access from different
apps within the same domain to the same datastore. Amazon Web Services SDB system
is very good like that: you can have a hardened public-facing app, and a softer admin
app running on-demand behind your firewall with completely different login
requirements.

I think this issue is not clear and it should be split into two separate issues.

The title is "Shared data store across multiple appengine accounts", but the
description gives this example: "Let's say I want both python and java
applications but I want them to share the same data store."

In order to access a datastore from different applications running on different
platforms we just need to be able to share data between applications.  Sharing
between accounts is a different matter.

Sharing data between applications can be application-specific and can be implemented at the level of
applications through their APIs. Sharing data at the level of JDO inside applications would however be very
helpful.

I'm not clear on this issue.  Is it possible to share data between application in the same account?

[Comment deleted]

I take this to mean 'multiple applications' rather then 'multiple accounts'. If this is the case I would like the ability to do the same.

I like to work with data saved in one GAE application in other GAE applications. Basically share the datastore between multiple web applications in Google App Engine (Python) Development and Production.

I haven't tried this, but if you want to run multiple applications under the same datastore, you might be able to create a different "versions" and have multiple versions deployed at one time. One version could be primary and other other could be a completely different app. I am not sure what would happen when you deploy java and python apps at one time.

I would also absolutely love to see this. Especially given the limits of using e.g. something like url_fetch to communicate data between apps.

I would also absolutely love to see this. Especially given the limits of using e.g. something like url_fetch to communicate data between apps.

Same here : I have 2 applications that share the same data model.
I would love to be able to use the same datastore for both of them.

A security note.

Please consider this when implementing this feature:

Some apps may be doing something like:

greeting = db.Key(greeting_key)
if greeting.kind() != 'Greeting':
   raise 'Invalid Greeting'

And they expect that only their own data will be returned by db.Key. If suddenly, db.Key starts returning data they don't expect, it could have terrible security consequences.

An easy approach to sharing the datastore accross different applications would be usefull.

We can already somewhat do this via the RemoteAPI, but that incurs extra costs and overhead for the HTTP requests.

Using the lower-level API directly, you can even now issue queries against different applications' data stores (but they get turned down with "permission denied").

It would be very cool if you could in the admin pages say which other apps have access to your datastore, and then the lower-level API would get these permissions (and higher-level API could be build on top pf that).

One can also imagine per-entity permissions, but that would mean a lot of additional settings. Maybe at least a "full-access/read-only" toggle.

Billing would also be interesting. I suppose if you query another data store, only you pay (with Remote API currently the provider pays). If you create entities, it will have to count against the provider's quota, though.

Using OAuth, these access permissions could also apply to outside access (then using HTTP via RemoteAPI).

OK Thiloplanz, it would be nice to have that option(additional permission settings in admin) ... why you don't just do it ? Or open-source the platform and I will do it :) just kidding

Bulk edit:
Mark escalated issue as Accepted

Shared data store of one applications from another applications on same account?
please hellllllllp

I just ran across this issue because I was looking for exactly the same thing.  In my case, I've developed my own Python application, and I've also downloaded an open source CMS (as a separate application for GAE), and I want my own application to read the data written by the open source CMS.  I don't want to modify the CMS to expose its data - I just want to read the CMS's data store stuff directly.

Fortunately for me both applications are in Python so my work around for now is to manually merge these two applications together, which I really don't like because I have to make changes to the open source project just for me.

One more option that may or may not work for you would be to consider using CloudSQL, https://developers.google.com/cloud-sql/.  However this would only really be relevant if your apps were sharing a MySQL type DB in the back end.  And even then may require some serious re-design.  Google has been adding more Datastore tools in the console to copy data between apps, but this is a far cry from sharing data across apps.
-Jim

Hi Jim,

Thanks for your comment.  I'm wondering about that code in the Datastore part of the console you mentioned, that copies data across apps.  Perhaps whatever mechanism that console code uses to get access to the data across apps could also be used by app developers like me to copy the data across?  That way I could write code to copy the data from one app to another.  Wonder if anyone knows whether that level of API access is exposed to developers, or is a private/privileged API that I can't access?

David

Hi,

Is there any progress on this yet? Adding this feature would really extend the enterprise capabilities of the GAE environment. For example:-

1) allowing us to properly segregate our codebase into an SOA (at the moment its all or nothing)

2) allowing us to properly maintain versioned APIs (although the GAE version control systems are lovely; they have limitations upon the number of versions that can be maintained and don't appear to include backends and suchlike - fine for release management but not for managing full versioned systems).

Kindest

Steve

Hi, this topic is what I am looking for.
I am planning to develop a web application accessed by general users.
That app needs admin screens where admin users can register the data.
User screens and admin screens need to share the same datastore.

I want to minimize the downtime of this app, but if user screens and admin screens are in the the same app, I have to bring the entire system down for the deployment of the modification of the admin screens.

Is it a good solution for this to use the different app versions under the same application ID? Any issues on this?
I would like to follow the GAE standard.

Dai

Over on StackOverflow I documented a partial work-around here: http://stackoverflow.com/questions/9456971/any-issues-using-multiple-gae-app-versions-to-get-multiple-apps-to-share-the-sam.

The main limitation is that the different applications have to cooperate as different versions of the same app.  If you do that, you can share a datastore across two totally different applications.  This is not as good as if Google implemented this request 1300 by creating an admin feature that would allow any two apps (and their versions) to share the same datastore.  But it's been working for me.

I vote for a support of sharing datastore across multiple apps.

me too, voting for sharing datastore across multiple apps.

I vote for sharing datastore, so I can access the same data from different apps

I vote for a support of sharing datastore across multiple apps.

Cloud Datastore (https://developers.google.com/datastore/) lets you access the same datastore from multiple apps (and from outside of appengine as well).
Additionally we are adding "Servers" which make it easier to deploy multiple "servers" to the same app, see http://googlecloudplatform.blogspot.com/2013/05/ushering-in-next-generation-of.html

One of the problems with Cloud Datastore is that it does not have a high-level ORM API like App Engine Datastore has. I'd love to be able to use Cloud Datastore from GAE and GCE, but the API/tools are lacking.

100% Agree with the previous comment, without compatibility with NDB, it's not all that useful.

(not yet at least ;-))

Why can't we have one datastore for multiple apps? What's stopping google?

I believe you can now: https://developers.google.com/datastore/

I'm not sure why this is taking so long to complete, this has been in Status: Accepted for over a year. Seems like a small change.

All I like to do is share data store of one applications from another applications on same GAE account. (Not with versioning)

Thank you, for any updated on this change

Check out the link in #36.  The datastore has a full API now.  You ran run one datastore instance and access it from multiple GAE apps, separate web apps, whatever you like as long as you authenticate into Google to access it.  

Datastore users: we hear you loud and clear!

We are working on easy access to multiple Datastores from within one App Engine app as part of a larger set of related changes.

It is more complicated than it might seem because an app and its Datastore are currently bound together in App Engine to make authentication and some caching simpler and more efficient.

We're taking the time to do it right, to make it as seamless as possible, and to make sure that it will work well with other improvements we're planning for Datastore so it's taking longer than we would like.

Thank you very much for your patience and for using Datastore!

That's great news. I'd like to use a different app id, because at the time that I registered mine I chose an obvious one, and now for security reasons I'd like to make an obscure one but can't do that if the datastore is bound to the app id.

Thank you, for the update.
I think this is a critical option, especially for corporate users.

JacobSGur: Just to note that your Datastore data would still be tied to its app and thus app id; this would just make it easier to access that Datastore from another app.

Sharing NDB data between my apps is very much needed. Could you please update about an expected timeframe for this feature enhancement ? Thanks.

https://cloud.google.com/datastore/ effectively let's you do this now. You can grant service accounts access to your datastore and they can access it from other apps or from other services altogether.

Any news on this?  We need the NDB library to be able to connect to other app's datastore...

+1