Back-end server for Play 2 framework app

https://stackoverflow.com/questions/15055248

11-03-2022
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Pergunta

I'm planning a web application where users will be able to upload and process their files. The specifics of the application are irrelevant to my questions, but lets assume that the application will deal with mp3 audio files. I'm going to split my application in two distinct parts: the front-end and the back-end.

The front-end application will be a usual web application serving html pages to users. Typically a user will upload his file and fill an html form to specify which operations he would like to perform on the file. The files will be initially uploaded to a storage facility, such as Amazon S3, and later processed by a back-end server. I'm using Play 2.0.4 framework to develop the front-end application and this is going very well for me. I managed to implement user authorization, drafted most of the UI and also implemented file upload to S3. The application is currently deployed on Heroku without any problems.

For my back-end server I'm considering to use Play 2 framework once again. The back-end server will receive notification (http request) from the front-end server about creation of a new job. Job specification will include a link to the original user file in the storage and arguments describing the job. The job should be added to a queue. Now the most important part is to delegate the actual processing job to a third party program, which most certainly will be a compiled command line utility, such as SoX for the case of audio processing, written by good people using a programming language of their choice. As far as I know it is possible to call an external program from java, pass command line arguments and collect the result. After processing is done, the back-end server will upload processed file back to storage, and send notification (http request) to the front-end application, which will store a link to the processed file and display it to the user at some later time. To be able to use command line utility I'm going to deploy the back-end application to a Amazon EC2 instance with a Typesafe stack installation.

Here are some questions about this basic plan:

Is Play 2 a reasonable choice for the back-end, or should I look into alternatives? One of them seems to be CGI, which according to Wikipedia "is a standard method for web server software to delegate the generation of web content to executable files." Unfortunately I don't have any experience with that.
There shouldn't be any problem implementing a job queue with Play?
Is it possible to install a command line utility on EC2 and call it from Play?
Should I expect any problems installing Typesafe stack on the EC2? This post briefly describes what I'm planning to do https://www.assembla.com/spaces/bufferine/wiki/Typesafe_stack_on_Amazon_EC2
Assuming that in the future the application will grow, how would I split the jobs among multiple instances on EC2? Should I create a separate job-balancing application in between my front-end and back-end?

I would appreciate any advice! Thanks!

Note: I'm using Java api for Play 2 framework, since I'm not familiar with Scala language.

Solução

You may consider Akka for processing and it's built in Play2. It will help you to manage tasks easily, and even saving hardware ressources if used with advanced features. There is a Java API that should cover all your needs. And it's not necessary in a backend APP, if you need more power you can scale even better with two same instancies. Play and Akka are stateless, you can just add new instances to scale. To make it run on EC2, just use the play dist command.

And yes, you can install whatever you want in EC2 and call it from your app.