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SwiftObjectStores

A Julia Library for moving Data onto and off-of OpenStack Swift Object Stores

Readme

SwiftObjectStores

Swift is a highly available, distributed, eventually consistent object/blob store. Organizations can use Swift to store lots of data efficiently, safely, and cheaply.

Makes Open Stack Swift Object Stores available from within Julia. This package wraps the Python Swift Client, but makes significant changes in terms of interface.

The implementation makes significant uses of temporary files. It is thus desirable to ensure your TMPDIR is set to be on a RAM disk. In most modern unixen, this is done by adding export TMPDIR=/dev/shm to your .bashrc or similar. The package will work fine without this -- and depending on your OS may effectively use a RAM disk anyway.

Notice:

I no longer have free access to any swift object store service provider, so I can no longer perform the integration tests used for this package. As such my ability to maintain this package moving forward is limitted.

In general, I have switched to mounting the object store as a file-system. E.g. with svfs. While this has some pecularatities (e.g. running ls is expensive, so tab completion is slow), it is really quiet handly, and works well with julia code that has been written to expect paths to be provided as strings to a local filesystem.

Installation

Pkg.add("SwiftObjectStores")

This will install the package, and its python reqs, if you are using Conda for your python install. If you are not using Conda, the on screen instructions will tell you what is neeeded.

Examples of use:

In all these examples, assume we have already loaded the package, and set up a server description:

julia> using SwiftObjectStores
julia> serv = SwiftService()

This constructs the default server connection description. Reading the server URL, and your identity information from the enviroment variables, as is the Open Stack fasion. If you want to make use of this feature, you should source ~/openrc.sh or similar, before starting julia.

Using Storing and Retrieving arbitary data objects via JLD

We expose the capacity for storing, and retieving arbitary julia object, through JLD.

We store them, by name and to value, using keyword arguents

julia> put_jld(serv, "testing-out-swift-container", "usefulobject"; data = rand(Complex128, 10), note="Stored some random numbers for later")

As when using JLD on files, we can retrieve each field one at a time:

julia>get_jld(serv, "testing-out-swift-container", "usefulobject", "note")

"Stored some random numbers for later"

julia>get_jld(serv, "testing-out-swift-container", "usefulobject", "data")

10-element Array{Complex{Float64},1}:
0.37839+0.805684im
0.300178+0.318451im
0.240708+0.331851im
0.0149401+0.806278im
0.416414+0.825936im
0.63335+0.239163im
0.661586+0.242519im
0.640306+0.611966im
0.538004+0.123092im
0.749919+0.861574im

or all at once:

julia>get_jld(serv, "testing-out-swift-container", "usefulobject")

Dict{String,Any} with 2 entries:
    "note" => "Stored some random numbers for later"
    "data" => Complex{Float64}[0.37839+0.805684im,0.300178+0.318451im,0.240708+0.…

Get a file, and perform a loading operation on it

Use RData.jl to load a RData file off the object store. Using the container ResearchData, the pseudodir simulated, and the object name sim-100000.RData. Note that the pseudodir is part of the object name -- pseudodir's are not real, just convention in the key value store.

julia> using RData
julia> data = get_file(serv, "ResearchData", "simulated/sim-100000.RData") do fn
    load(fn)
end

Management:

Deleting object, and containers

Delete an object in a container:

julia> delete(serv, "testing-out-swift-container", "usefulobject")

Delete the container itself:

julia> delete(serv, "testing-out-swift-container")

Listing Containers

the list command gives a dictionary, where the keys are the names of the containers, and the values contain information about each.

julia> SwiftObjectStores.list(serv) |> keys

Base.KeyIterator for a Dict{String,Dict{Any,Any}} with 11 entries. Keys:
  "testing-out-swift-container_segments"
  "ResearchData"
  "testing-out-swift-container"

Notice, segment containers are also listed.

First Commit

09/08/2016

Last Touched

2 months ago

Commits

47 commits

Used By: