Is it possible to have 2 different applications (one written in Python and one in Java) in the same App Engine environment (Standard) and have them view the same Datastore?
From my understanding, Google Cloud Datastore is the storage option that comes along with any AppEngine application, but also exists as an external service any application can use.
Is there a way for one application to view the other application's "embedded" Datastore (without one application exposing an API to it)? If not, how can 2 different applications use the same storage? I haven't been able to find any documentation regarding Cloud Datastore urls or using them as a third party database.
You probably can use the REST API version https://cloud.google.com/datastore/docs/apis. The real question is, why do you need to 2 different apps here? Micro service is usually implemented in appengine using module on a single app, https://cloud.google.com/appengine/docs/standard/python/microservices-on-app-engine.
Related
Im creating a Node.js website that probably won't have loads of traffic, and was looking into cheap solutions to host the site. Came across Google cloud services offering free usage for their services with limits. A f1-mirco is more than enough for my needs, but I will happily pay for some usage if it goes over by any chance.
I wanted to setup a linux centOS 7 on GCE (which I already did), and run my application and REST API on it. Now here comes the problem.
I tried to use Google's datastore service, but it sprung an app engine instance and without it datastore won't work.
Is datastore entirely relying on app engine to function?? In the docs, it said if you use any of the client API, it requires app engine. What can I do to not use the client api and query data then? Don't want to use the app engine at the moment or datastore is just not for me then?
Thanks for any help!
Some of the underlying infrastructure of Cloud Datastore and App Engine are still tied together for creation, etc. So while creating an Cloud Datastore database also defines an App Engine instance for the project, it doesn't require you to use it. You don't get charged for App Engine either, unless you decide to deploy an App using it.
You should be totally fine use the Google Cloud Node client library on the f1 micro instance.
I have previously used
#app.route('/mypage/<int:myvariable>/')
to create rules for what should happen when users land on different urls on my website. I have done this on local machines that have been running on my own virtual servers.
Now I am learning to publish my first web app to Google App Engine. I have heard that I should be using Google Cloud Endpoints instead of the route decorator.
#endpoints...
I've read a few articles about endpoints and some of the benefits of endpoints that they list are:
Endpoints makes it easier to create a web backend for web clients and mobile clients
Endpoints free you from having to write wrappers to handle communication with App Engine
Even if I have read this I can't wrap my head around what this means. I don't understand it. Can you explain in non-technical terms with examples what the advantages of using #endpoints is compared to alternatives? The alternative that I am familiar with is #app.route.
Google Cloud Endpoints can be thought of as a subset of #app.route. They are intended to solve the API backend problem for mobile and javascript clients. They are not intended to serve web pages and other hypermedia. You can use the normal routing methods of your framework of choice to create a web service for your application but Google Cloud Endpoints takes care of a lot of boilerplate for you.
There are a lot of limitations with Google Cloud Endpointsso be sure to familiarize yourself with them before committing. For one, you cannot host Google Cloud Endpoints on a custom domain name. They are only accessible via <app_id>.appspot.com/_ah/api/*
Endpoints makes it easier to create a web backend for web clients and
mobile clients
What this means is that you can create one backend and then iOS, Android and Web-apps (via Javascript for example), can execute your API methods with specific client generated libraries.
This is convenient if you are building a backend that you want to be easily accessed via smartphones or through a web browser.
Endpoints free you from having to write wrappers to handle
communication with App Engine
With Endpoints you can generate client libraries (e.g. Android, iOS, Javascript) that you can then execute your API methods. You don't have to worry about writing a bunch of additional code to do that.
My Opinion:
I have never used Cloud Endpoints to make a web-app but it is very convenient if you are making a mobile app for iOS and Android because you can access your backend with both platforms.
One reason you might want to use Cloud Endpoints for a web-app instead of something else is because of Datastore. Datastore is the way Cloud Endpoints stores data. It is a NoSQL storage method which is kinda tricky to wrap your head around at first if you come from a relational database background, but once you get it, it makes a lot of sense.
Is it possible for one GAE application to access the datastore of another GAE application (both applications are hosted under the same Google account) using Objectify? If so, how can I pass service account credentials to Objectify (which API calls)?
It is not possible. Objectify is a very simple and convenient lightweight ORM that sits on top of a GAE Datastore, thus shielding the developer from most of the complexities of using JDO/JPA.
Nowhere in the documentation have I seen the scenario you describe mentioned because that is not the problem it is trying to solve.
I suspect what you will probably need to do is create a Web Service that exposes your GAE application (whose data you want) through an API. Then have your other GAE application call those service methods to obtain the data it needs.
Alternatively, you can use something called remote_api. It allows you to access and manipulate a GAE Datastore remotely.
Below are some links I just found to similar questions after posting my answer:
Can I access Datastore entities of my other Google App Engine Applications
Can one application access other applications data querying the key in Google App Engine?
A solution is to have only one "GAE application" but to make different Modules in your application. The Datastore will be shared between the modules.
Another solution is to use the Remote API (https://developers.google.com/appengine/docs/java/tools/remoteapi), but you won't be able to use Objectify, I think...
We are currently running a combined AppEngine / GCE app and thus far have kept all of our datastore access on the AppEngine side of things. Now we are exploring also allowing our GCE instance to make some queries into the (shared) datastore. To start, I'm trying to figure out how to run things locally. What we have so far:
A Go devappserver running
A Go standalone binary that wants to issues queries to the devappserver datastore.
We installed ('go get') google-api-go-client/datastore/v1beta2 so that we can use an API instead of issuing direct HTTP calls. However we are definitely willing to issue direct HTTP calls if this API library won't work in development.
We have service accounts set up (we already access GCS from GCE) but I doubt that's relevant for running locally...
I've seen some docs but they (a) only talk about Python & Java, and (b) discuss connecting to the (standalone) development datastore server, as opposed to the datastore embedded in AppEngine's devappserver (if those are even different?). There is also the following answer here on StackOverflow, but again it discusses connecting to the standalone development datastore server:
How to connect to the local google cloud Datastore db?
Any pointers would be much appreciated!
Ian
Currently this is not possible in the development environment for several reasons. The Google Cloud Datastore tool (gcd.sh) uses the java development server. However when developing go for App Engine you use the python development server, which has different underlying storage. There is a bug to track this issue on the github page.
You can still develop a Google Cloud Datastore application in go however there are many bugs in the current go client library. Unfortunately, the development server does not currently support the JSON API, which the go library uses (see the note at the top of the page).
Update: I wanted to make sure proppy's comment was seen as part of the answer. His suggestion does provide a way to use the protocol version of the API, which is probably more stable than the go client library above. It could also let you use the gcd.sh tool to test this in the development server. You will have to craft the HTTP requests yourself though, and you won't be able to share the data in the datastore between your application and the Cloud Datastore in development. However it is definitely a good workaround and lets you use the Cloud Datastore API, which as it develops will be easier to work with than other workarounds.
From proppy:
Note that you can still use Cloud Datastore Protobuf HTTP API with Go. The protobuf definition is available on GitHub, you can compile it to Go code using the Go protobuf compiler plugin and then send POST HTTP requests to /datastore/{version}/datasets/{datasetId}/{method}.
If the use case from your "GO" app server is straight forward enough, you may want to implement access by using an API call to your GAE service (perhaps extending the service to receive the API calls).
This has the added benefit of only having to make changes in one place if your datastore definitions or functions change.
I am interested to build a platform on Google App Engine where one Master App provides common functionality to several child Apps (Web portals).
Master App:
Offers Common Social Networking features
Common user database
Interacts using Web services API
Child Apps (Web Portals):
Connects to Master App for user database and social networking features
Uses Local business logic for local features
My Design plan is:
Master and Child Apps will be
individual Apps on GAE Appspot (for
easy management)
All will communicate via REST/JSON?
I will enable billing for all Apps so
nothing is against Google's usage
policy.
Will use SSL for login into Master App, later use a token
(cookie) for further interactions
Could anyone kindly spot risks and suggest any improvements?
Your "Master/Child" concept will be hard to maintain, introduce issues with cross-site-scripting and most importantly be completely against Google App Engine's terms of service for combining multiple apps into one.
4.4. You may not develop multiple Applications to simulate or act as a single Application or otherwise access the Service in a manner intended to avoid incurring fees.
You could use multiple app versions (defined on app.yaml) to deploy different codebases to the same appspot.com subdomain, and access them like http://app1.myapp.appspot.com, http://app2.myapp.appspot.com for "versions" app1 and app2. You could even have one version running on Java and another one on Python.
They'll all share the same datastore, although you'd be able to use namespaces to separate them if necessary.
For the distributed nature of the architecture you proposed, I'd suggest having a deep look at Facebook's graph API and Twitter's API. They both use oAuth for authentication/authorization and already have a proven implementation of what you're trying to accomplish.