Crate ecpool

This crate provides thread pool(ErasureCoderPool) for managing executions of erasure coding.

ecpool also provides ErasureCode trait defines erasure coding interface and of which implemtations can be executed via ErasureCoderPool.

There are some built-in implementations of the trait:

• LibErasureCoder:
  • This implementation uses liberasurecode crate that is a wrapper for openstack/liberasurecode library.
  • It is highly optimized and stable but only available in Unix environments.
• ReplicaCoder:
  • This implementation simply replicates the input data.
  • It is provided for example and testing purposes only and not intended to use in production.

Build Prerequisites

It is required to install openstack/liberasurecode and its dependencies by executing the following commands before building this crate:

$ git clone https://github.com/frugalos/liberasurecode
$ cd liberasurecode && sudo ./install_deps.sh

Examples

Basic usage:

use ecpool::replica::ReplicaCoder;
use ecpool::{ErrorKind, ErasureCoderPool};
use std::num::NonZeroUsize;
use std::result::Result;
use trackable::error::{Failure, Failed};

// Creates a pool
let data_fragments = NonZeroUsize::new(4).ok_or_else(|| Failure::from(Failed))?;
let parity_fragments = NonZeroUsize::new(2).ok_or_else(|| Failure::from(Failed))?;
let coder = ErasureCoderPool::new(ReplicaCoder::new(data_fragments, parity_fragments));

// Encodes
let data = vec![0, 1, 2, 3];
let encoded = fibers_global::execute(coder.encode(data.clone()))?;

// Decodes
assert_eq!(
    Some(&data),
    fibers_global::execute(coder.decode(encoded[0..].to_vec()))
        .as_ref()
        .ok()
);
assert_eq!(
    Some(&data),
    fibers_global::execute(coder.decode(encoded[1..].to_vec()))
        .as_ref()
        .ok()
);
assert_eq!(
    Some(&data),
    fibers_global::execute(coder.decode(encoded[2..].to_vec()))
        .as_ref()
        .ok()
);
assert_eq!(
    Err(ErrorKind::InvalidInput),
    fibers_global::execute(coder.decode(encoded[3..].to_vec())).map_err(|e| *e.kind())
);

Modules

liberasurecode	An ErasureCode implementation based on openstack/liberasurecode.
replica	An ErasureCode implementation that simply replicates the input data.

Structs

ErasureCoderPool	Thread pool for encoding and decoding data by using an ErasureCode implementation.
Error	This crate specific Error type.

Enums

ErrorKind

Possible error kinds.

Traits

BuildCoder	This trait allows for building instances of an implementaion of ErasureCode trait.
ErasureCode	This trait allows for encoding and decoding data by using some erasure coding algorithm.

Type Definitions

Fragment	A fragment.
FragmentBuf	An owned fragment.
Result	This crate specific Result type.