What weaknesses can be found in using Erlang?

Question

I am considering Erlang as a potential for my upcoming project. I need a "Highly scalable, highly reliable" (duh, what project doesn't?) web server to accept HTTP requests, but not really serve up HTML. We have thousands of distributed clients (other systems, not users) that will be submitting binary data to central cluster of servers for offline processing. Responses would be very short, success, fail, error code, minimal data. We want to use HTTP since it is our best chance of traversing firewalls.

Given this limited information about the project, can you provide any weaknesses that might pop up using a technology like Erlang? For instance, I understand Erlang's text processing capabilities might leave something to be desired.

You comments are appreciated. Thanks.

Answer 1

This sounds like a perfect candidate for a language like Erlang. The scaling properties of the language are very good, but if you're worried about the data processing abilities, you shouldn't be. It's a very powerful language, with many libraries available for developers. It's an old language, and it's been heavily used/tested in the past, so everything you want to do has probably already been done to some degree.

Answer 2

Make sure you use erlang version R11B5 or newer! Earlier versions of erlang did not provide the ability to timeout tcp sends. This results in stalled or malicious clients being able to execute a DoS attack on your application by refusing to recv data you send them, thus locking up the sending process.

See issue OTP-6684 from R11B5's release notes.

Answer 3

I understand Erlang's text processing capabilities might leave something to be desired.

The starling project already provides basic unicode support and there is a EEP (Erlang Enhancement Proposal) currently in draft, but going in to bring it into the mainstream of Erlang/OTP support.

Answer 4

With Erlang the scalability and reliability is there but from your project definition you don't outline what type of text processing you will need.

I think Erlang's main limitation might be finding experienced developers in your area. Do some research on the availability of Erlang architects and coders.

If you are going to teach yourself or have your developers learn it on the job keep in mind that it is a very different way of coding and that while the core documentation is good a lot of people do wish there were more examples. Of course the very active community easily makes up for that.