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README.md

README.md

Introduction

This is a data collector for lexigraph. It just uses functions exposed by the public API, so there's really nothing special here. That said, it does have a few compelling features:

  • Batched updates -- all updates are batched so that updates happen at most once every ten seconds. This is much more efficient than sending dozens of non-batched updates that each update just a single dataset.
  • Efficient -- all code here is implemented using node.js, and all processing happens in process (by reading various things out of /proc). This means that there's no additional overhead to e.g. invoke external processes to find out CPU usage.
  • Asynchronous -- all code is run as part of a single asynchronous event loop, which means that there's no way that any module can block any of the other modules from running. Since this asyncrhonicity all happens within a single process, the CPU/memory overhead of threaded solutions is absent.
  • Extensible -- all of the collector code is implemented using a plugin system, so it's easy to modify the plugins or add your own.

I've made an attempt to make the plugins somewhat modular, so you should be able to pull out just the stuff that interacts with /proc if you want to use it for your own purposes. Also, this code is probably easier to decipher than reading the C code for procps.

Everything here is released under a two-clause BSD license (see the LICENSE file). Enjoy.

Namespaces

All of the blessed plugins live in the lib directory and have the prefix lx_, so you'll see plugins like lx_cpu.js, lx_load.js, etc. If you write your own plugins, you should give them names that don't start with this prefix. For instance, if you write an Apache plugin it would be appropriate to give it a name like apache.js; if an "official" Apache plugin is released later it will have a name like lx_apache.js and therefore won't conflict with your own.