Pemmican
Pemmican is a Web server library built in top of hyper for the Rust language.
Caveats and Warnings
Pemmican is very new (it was started in June 2017), and is likely to undergo substantial changes. If you use it now, expect breaking changes. We expect it won't be generally useful until sometime after hyper 0.12 is released.
The plugin architecture is especially new, quite limited at present, and very likely to break multiple times before it settles down.
Overview
Pemmican is (or should be, once the issues are fixed)
- fast (rust)
- parallel (thread pool)
- asynchronous (hyper 0.11 w/ futures)
- modular (plugins)
- not opinionated (configurable and general purpose)
- lets you share global state
Pemmican is fast
Pemmican is written in rust, a systems level language that generates code that typically runs at about the same speed as the other fastest compiled languages available (such as C and C++).
We attempt to minimize memory allocation, eschew blocking I/O, and try to use the fastest algorithms available. This is an ongoing effort.
Performance testing remains to be done. Initial performance testing shows pemmican to be very slow, and an issue is raised for this. The cause is still unknown.
Pemmican is parallel
Pemmican provides a thread pool. You can choose to run your page handler logic on a pre-existing thread from the thread pool.
Pemmican is asynchronous
Pemmican uses the new asynchonous version of hyper, (based on tokio, futures, mio, etc). This means that whenever a task is unable to continue right away, your processor cores can move on to something else, keeping them busy whenever any task is able to progress, rather than sitting idle waiting for an event.
In order to keep your cores busy whenever work becomes available, you must be sure that the Future your page handlers return is not calling into blocking I/O functions. If any of them are, you can still use pemmican to great effect but you probably want to configure a much larger thread pool. If you never call a blocking I/O call, then theoretically you should get maximum performace with one thread per core.
Pemmican is modular
Pemmican is a rust library. It is generic, and does not define your website. You define routes and add them dynamically.
Pemmican supports plugins, so that functionality can be added via separate crates, and more importantly so that functionality you don't want can be left out.
Pemmican is not opinionated
Pemmican lets you configure various settings of the libraries it depends on,
rather than choosing for you. This includes (as of this writing) num_threads,
shutdown_timeout, and keep_alive. We aim to be as configurable as possible,
only making choices when we absolutely must.
Pemmican lets you define the Error type you will use, as long as it is
Error + Send + Sync + 'static.
Pemmican lets you share global state
Pemmican lets you share global state between your handlers, as long as it is
Send + Sync + 'static.
Example
Other similar crates
Other authors are also working towards similar goals. Have a look at the following projects which also use asynchronous hyper to provide a web services:
- zircon
- backtalk
- pronghorn
- jsonrpc-http-server
- As of July 2017, that is about it (there are 37 crates that depend on hyper 0.11, and it seems only these 4 try to be a web server)
Additionally consider these more mature frameworks running on synchronous hyper: