What alternatives are there to Google App Engine?
I don't think there is another alternative (with regards to code portability) to GAE right now since GAE is in a class of its own. Sure GAE is cloud computing, but I see GAE as a subset of cloud computing. Amazon's EC2 is also cloud computing (as well as Joyent Accelerators, Slicehost Slices), but obviously they are two different beasts as well. So right now you're in a situation that requires rethinking your architecture depending on your needs.
The immediate benefits of GAE is that its essentially maintenance free as it relates to infrastructure (scalable web server and database administration). GAE is more tailored to those developers that only want to focus on their applications and not the underlying system.In a way you can consider that developer friendly. Now it should also be said that these other cloud computing solutions also try to allow you to only worry about your application as much as you like by providing VM images/templates. Ultimately your needs will dictate the approach you should take.
Now with all this in mind we can also construct hybrid solutions and workarounds that might fulfill our needs as well. For example, GAE doesn't seem directly suited to this specific app needs you describe. In other words, GAE offers relatively high number of requests, low number of cpu cycles (not sure if paid version will be any different).
However, one way to tackle this challenge is by building a customized solution involving GAE as the front end and Amazon AWS (EC2, S3, and SQS) as the backend. Some will say you might as well build your entire stack on AWS, but that may involve rewriting lots of existing code as well. Furthermore, as a workaround a previous stackoverflow post describes a method of simulating background tasks in GAE. Furthermore, you can look into HTTP Map/Reduce to distribute workload as well.
As of 2016, if you're willing to lump PaaS (platform as a service) and FaaS (function as a service) in the same serverless computing category, then you have a few FaaS options.
Proprietary
AWS Lambda
AWS Lambda lets you run code without provisioning or managing servers. You pay only for the compute time you consume - there is no charge when your code is not running. With Lambda, you can run code for virtually any type of application or backend service - all with zero administration. Just upload your code and Lambda takes care of everything required to run and scale your code with high availability. You can set up your code to automatically trigger from other AWS services or call it directly from any web or mobile app.
AWS Step Functions complements AWS Lambda.
AWS Step Functions makes it easy to coordinate the components of distributed applications and microservices using visual workflows. Building applications from individual components that each perform a discrete function lets you scale and change applications quickly. Step Functions is a reliable way to coordinate components and step through the functions of your application. Step Functions provides a graphical console to arrange and visualize the components of your application as a series of steps. This makes it simple to build and run multi-step applications. Step Functions automatically triggers and tracks each step, and retries when there are errors, so your application executes in order and as expected. Step Functions logs the state of each step, so when things do go wrong, you can diagnose and debug problems quickly. You can change and add steps without even writing code
Google Cloud Functions
As of 2016 it is in alpha.
Google Cloud Functions is a lightweight, event-based, asynchronous compute solution that allows you to create small, single-purpose functions that respond to cloud events without the need to manage a server or a runtime environment. Events from Google Cloud Storage and Google Cloud Pub/Sub can trigger Cloud Functions asynchronously, or you can use HTTP invocation for synchronous execution.
Azure Functions
An event-based serverless compute experience to accelerate your development. It can scale based on demand and you pay only for the resources you consume.
Open
Serverless
The Serverless Framework allows you to deploy auto-scaling, pay-per-execution, event-driven functions to any cloud. We currently support Amazon Web Service's Lambda, and are expanding to support other cloud providers.
IronFunctions
IronFunctions is an open source serverless computing platform for any cloud - private, public, or hybrid.
It remains to seen how well FaaS competes with CaaS (container as a service). The former seems more lightweight. Both seem suited to microservices architectures.
I anticipate that functions (as in FaaS) are not the end of the line, and that many years forward we'll see further service abstractions, e.g. test-only development, followed by plain-language scenarios.
AppScale
AppScale is a platform that allows users to deploy and host their own Google App Engine applications. It executes automatically over Amazon EC2 and Eucalyptus as well as Xen and KVM. It has been developed and is maintained by AppScale Systems. It supports the Python, Go, PHP, and Java Google App Engine platforms.
http://github.com/AppScale/appscale
In the mean time...
...it is amost 2015 and it seems that containers are the way to go forward. Alternatives to GAE are emerging:
Google has released Kubernetes, container scheduling software developed by them to manage GCE containers, but can be used on other clusters as well.
There are some upcoming PaaS on Docker such as
- http://deis.io/
- http://www.tsuru.io/
- even Appscale themselves are supporting Docker
Interesting stuff to keep an eye on.
Alternatives: 1. AppScale 2. Heroku.
Ref: Alternative for Google AppEngine?