I have a Dynamic Backend setup on GAE which I want to run using cron every 15mins. The problem is cron requires a url that begins with "/". While a backend URL uses the following format: http://backendname.yourapp.appspot.com.
I've read in other forums that you could use fetchurl to call your backend but I don't think that's the ideal way. Because that would require you to make your backend publicly accessible.
According to google's documentation:
http://code.google.com/appengine/docs/java/backends/overview.html#Public_and_Private_Backends
"Private backends can be accessed by application administrators, instances of the application, and by App Engine APIs and services (such as Task Queue tasks and Cron jobs) without any special configuration."
Has anybody got backends called by declaring it in cron.xml?
Use target tag to specify a backend in your cron.xml.
<?xml version="1.0" encoding="UTF-8"?>
<cronentries>
<cron>
<url>/long-task</url>
<description></description>
<schedule>every 30 minutes</schedule>
<target>name-of-the-backend</target>
</cron>
</cronentries>
urlfetch can be used to access internal-only URLs such as private backends - if that weren't possible, there'd be no way to communicate within your app! A better idea, though, might be to use the Task Queue, which can be configured to run tasks against a backend.
I haven't try google app engine's Backends functions, because its pricing model.
However, according to the documents:
http://code.google.com/appengine/docs/python/backends/overview.html#Public_and_Private_Backends
Backends are private by default, since they typically function as a component inside an application, rather than acting as its public face.
I think GAE will automatically hide the backend url from public http visiting (even without the needs to configure the app.yaml). You may test its behavior by logout and access the backend url directly.
Related
I have some appengine modules in my project.
I am building a "Cloud Endpoints" that will works like a API Gateway. Both in them same project.
The endpoints will receive a request and forward to another appengine module, so, when the module process the request, the endpoints will return the response to frontend.
The main reponsibility this API Gateway will be validate permissions and log informations.
The frontend sends: GET,PUT and POST methods.
I read about URLFetch to do it.
I would like to know, Is it fast to use URLFetch to to do it?
Should I use other framework to to id?
If you're on App Engine, external requests should use URL fetch regardless of if you use it directly or use your language level networking primitives. It should be relatively fast, though you should benchmark this for yourself to see if it's an acceptable latency.
I am trying to use Google Objectify for Datastore (https://github.com/objectify/objectify). My app is not hosted on GAE, but I still make use of Datastore, so I need to use the remote API. Right now, I use the low level API and connect successfully like this :
DatastoreOptions options = DatastoreOptions.builder()
.projectId("PROJECT_NAME")
.authCredentials(AuthCredentials.createApplicationDefaults()).build();
Datastore client = options.service();
And the library used is http://googlecloudplatform.github.io/gcloud-java/0.2.0/index.html. My application defaults for "AuthCredentials.createApplicationDefaults()" is in my home folder in development as well as on the server.
In the doc I saw for Objectify, I did not see anyway of specifying the connection like above, thus no way of telling to use the credentials file in our home folder. The code I see for Objectify is mostly like this Objectify.ofy(). So I see no way with this method of telling to use the auth credentials defaults.
Thank you very much.
Use the Google App Engine remote api:
https://cloud.google.com/appengine/docs/java/tools/remoteapi
You could try gcloud-java datastore module.
http://googlecloudplatform.github.io/gcloud-java/0.2.0/index.html
But I encounter some performance issues on outside of Google Sandbox (GAE-Compute Engine)
We are experimenting with Flexible Environment and we want to migrate an existing application. Everything seems to go well except from cron entries.
We have a bunch of cron and every url is secured as admin" (as stated in the documentation), but every time the url is hit by the cron service we get a 403 status, if the url is hit by the user via browser everything works well.
On standard environment everything is good.
Is there anything we can check about?
I assume you add login: admin in app.yaml handler section to secure cron service on Google App Engine standard environment.
But on App Engine flex, it changed how to secure your cron handlers like this (PHP example):
Check $_SERVER['HTTP_X_APPENGINE_CRON'] and if it's true, the requests are coming from App Engine cron service.
I was unable to access my Backend Instance at custom domain.
For example, I have an app and I access the Normal Instance sucessfully at:
http://www.[my_app_id].appspot.com or http://[my_app_id].appspot.com
And I have a backend config name=test and I accessed Backend Instance successfully at:
http://test.[my_app_id].appspot.com
In admin interface, the "Instances" link show the instances of Backend and Normal Instance separately. The content show is the same, but is easy to see when a request go to the Backend Instance and when go to Normal Instance.
Then I configured the wildcard "test" in Google Apps to access my Backend Instance at a custom URL:
I continue access the Normal Instance sucessfully at:
http://www.[my_domain].com or http://[my_domain].com
But request at
http://test.[my_domain].com
redicted to the Normal Instance instead of Backend Instance.
The doc's said it should work but I cann't at this moment and I need uses custom domain because my app is multitenancy.
What I do wrong?
Your backed is really supposed to be accessed by the front end, as I understand it.
So when your application front end makes a request to it's back end (e.g. via a URL), it'll work as it's all done internally.
Have you set your back end to be publicly accessible?
https://developers.google.com/appengine/docs/python/backends/overview#Public_and_Private_Backends
Backends are private by default, since they typically function as a component inside an application, rather than acting as its public face. Private backends can be accessed by application administrators, instances of the application, and by App Engine APIs and services (such as Task Queue tasks and Cron jobs) without any special configuration. Backends are not primarily intended for user-facing traffic, but you can make a backend public for testing or for interacting with an external system.
I don't know why the redirection is not working, but perhaps you should modify your question to show what problem it is you are trying to solve here and get an answer to that instead?
I am developing a GWT application on google app engine and I am looking for the best approach to initialize objects (like singleton, list, shared resources etc).
I guess I am looking for something like "Spring application context file"
any ideas?
What you're looking for is here:
http://code.google.com/appengine/docs/java/config/appconfig.html#Using_a_ServletContextListener
Basically, you're going to make a Servlet Context Listener, which is a part of the servlet API designed for exactly what you're referring to. If you're running this locally, it will run when you start your server. In the app engine environment it should run for every warm up request (to avoid, this, you can use "Always ON", which will be set here: http://code.google.com/appengine/docs/adminconsole/instances.html#Always_On)
Besides ServletContextListener you can also use <load-on-startup> to mark your normal servlet to be invoked during a warmup request.