This file acts as a controller layer and includes a number of functions that coordinate create, read, update. Click / >app-engine >bookshelf >model_datastore.py. •Model - The persistent data that we keep in the data store. Update Session. Google App Engine.

I got an answer to the below questions in this thread: but was recommended to ask here also. I try to figure out how easy it is to ruin/break the data in app engine's datastore by accident (using JDO). Assume that a class, say MyClass, has a number of 'persistent' members, e.g. Int a int b int c.

And assume a number of MyClass objects have been stored in app engine's persistent storage. Now, what will happen if. 1) a new persistent member variable, int d, is *added* to MyClass? The old objects in datastore did not have this variable, so what will their d-value be when they are fetched from datastore? 2) a persistent member variable, int b, is *removed* from MyClass? I guess the b field will be removed from all stored MyClass objects? If not, what will happen if b is re-added at some later point in time?

Will the stored MyClass objects now get their old b-value back? 3) the type of a persistent member variable is changed, e.g.

If a is converted to a String? What will the value of a be when the already stored objects are fetched from datastore?

By the way: the app engine docs focuses on JDO as the interface to the datastore. Is JDO particularly superior to the alternatives? (JPA, Objectify, Twig, SimpleDS, Slim3) Chau Huynh 28.03.10 20:23. You might want to use wrapper class (Long instead of long) to add new field to load existing data. To remove a property, you will need to update your Java class first, right?

Later retrieval of an instance, the field is not get loaded, then you save/persist and the field is gone. About changing property name, my thought is why do you want to challenge yourself on such matter?

Why don't you just 'remove' and 'add' a new field? In this series of articles explains what is behind your object, so it's not just your entity/class only, there're indexes as well. Reading the Google IO session, JDO/JPA is explained as the standard interface to access GAE service. Just in case you want to move your app out of GAE, you can still use the those. You might want to read other alternatives also; Twig, Objectify recently announced very cool features released.

I am having the same issue 'not an App Engine context'. There are about three slightly different workarounds floating around on here and stackoverflow, I have tried them all and they all fail. For example, the workaround two posts above doesn't work because we are trying to make a context.Context, so how can we pass one in to the helper function when we haven't been able to successfully make a context.Context yet? I have an appengine.Context, not a context.Context.

The workaround by gmlewis above doesn't work because it calls google.AppEngineTokenSource() with an appengine.Context, but apparently google.AppEngineTokenSource() takes a context.Context, so it doesn't compile. Pdf Edwards Est3 Fire Alarm Panel Manuals. The workaround posted here:, fails with 'Post. Not an App Engine context' And yet some people are saying some of these work for them. How is this possible if it doesn't work for me?

FYI, I am trying to use Exchange() from 'golang.org/x/oauth2' Go package on app engine, and since I need to pass it a context.Context, I am hitting this same bug. You will need to change your app to use 'google.golang.org/appengine' instead of 'appengine' as import path for any of these workarounds to work. The new import path uses context.Context instead of appengine.Context and has a few other API improvements, it will however take some effort to convert. On Sat, Mar 14, 2015 at 9:38 PM, Defcronyke wrote: I am having the same issue 'not an App Engine context'.

There are about three slightly different workarounds floating around on here and stackoverflow, I have tried them all and they all fail. For example, the workaround two posts above doesn't work because we are trying to make a context.Context, so how can we pass one in to the helper function when we haven't been able to successfully make a context.Context yet? I have an appengine.Context, not a context.Context. The workaround my gmlewis above doesn't work because it calls google.AppEngineTokenSource() with an appengine.Context, but apparently google.AppEngineTokenSource() takes a context.Context, so it doesn't compile.

The workaround posted here:, fails with 'Post. Not an App Engine context' And yet some people are saying some of these work for them. How is this possible if it doesn't work for me?

FYI, I am trying to use Exchange() from 'golang.org/x/oauth2' Go package, and since I need to pass it a context.Context, I am hitting this same bug. — Reply to this email directly or view it on GitHub. The updated code sample is failing to run. I could see this following error in the Log monitoring facility of the App Engine Developers console This request caused a new process to be started for your application, and thus caused your application code to be loaded for the first time. This request may thus take longer and use more CPU than a typical request for your application. Process terminated because the request deadline was exceeded. (Error code 123) I just want to write a string generated by the Go server on app engine into a file in the Google CLoud Storage, Isnt there a piece of code which could get this done easily on GAE Go Runtime!

The first thing to check is the App Engine logs to see if anything unusual happened. The second thing to realize is that requests on the default module are limited to 60 seconds. So it is possible that you may not want to run the full demo. Finally, if you just want to write a string into a file in GCS, then delete all the other processing done in the example and modify the 'createFile' example to print your string into the object. So, for example, you could change the 'createFile' function to be something like this. Firstly i thank for helping us out in fixing this.

Here is what that had went wrong 1.Had to Accept New Terms of Service at appengine.google.com. It would have been great if i would have been forcibly redirected to this page when i enabled the API's for the first time (because these terms are concerning the users of these API's ) 2. On the settings of the same page i had to create the default bucket. The Go Runtime sample code writes data into the default bucket, so if the default bucket for any reason if not yet been created the write or any other operation from the sample code fails. I had to click to create button below the Cloud Integration Heading which is seen in the image below.