In this page we present installation instructions for the gredia middleware platform. Specifically, we present instructions for the following components: RDLS, SFC, Gridtorrent.

RDLS

RDLS (Rich Data Location Services) is the layer that exposes the middleware's functionality through standard Web Services functionality. In the following, we give installation instructions of how to setup a gredia middleware server and how to install the client software and access the functionality of the installed services.

Server setup

RDLS is based on the web services layer of Globus Toolkit v.4. Globus can be installed as a whole, or only the web services layer. To install the whole toolkit, download the file  Globus Toolkit v.4.01 and follow the installation instructions from here. If you wish to install only the web services layer, download it from here and follow the installation instructions from here. When the installation is completed,download the gredia middleware services package  and install it using the following command:

globus-deploy-gar gredia_MetaData.gar

The source code can be found here

Client setup

The command line client software can be downloaded from here and the source code from here . The client software enables the user to perform rich queries and to store metadata descriptions on the RDLS. The client can be executed both from windows/linux machines with the only prerequisite is a java installation. After the zip is extracted, the directory config contains the file metadataclient.properties. The propery servername is the dns name of the server executing RDLS. The property proxyfile is the file name of a valid proxy certificate (that must reside in this directory). The executables have a .sh extension for linux and a .bat extension for windows. We now describe the client executables and their usage.

queryMedia : this executable is used to query the media overlay. It takes the following parameters: author date_created date_modified category type status privacy_status keywords(separated by " ").  When searching for a range, the attribute value must be replaced by from_value..to_value (with ".." between them). For the special ALL value, just give "..".

queryBanking : The same for the banking overlay. the parameters are the following: customer_name vat_number.

storeMedia: This executable is used to upload a metadata description to the overlay. the parameters are : path_to_local_filename  author date_created date_modified category type status privacy_status keywords(separated by " ")

storeBanking: Upload metadata description to the banking overlay. The parameters are: path_to_local_filename customer_name vat_number privacy_status.

SFC module and Kademlia overlay

This server software implements the component responsible for constructing a Kademlia-based overlay supporting the storage and querying of metadata files and can be downloaded from here. The indexing is based on Space Filling Curves (Z-curve or Hilbert curve). The initialization of the nodes that accommodate the enabled operations in the Metadata overlay is accomplished by the execution of peerPlatform.py. The description of the nodes and the indexing method is included in a INI file, which is given as parameter to the specific executable.

GridTorrent

GridTorrent constitutes the data transfer layer of the Gredia middleware. Based on peer-to-peer techniques, it allows clients to download files from multiple sources while uploading them to other users at the same time, rather than obtaining them from a central server. At the same time, it takes advantage of the striped version of GridFTP protocol to directly communicate with GridFTP servers. Moreover, instead of the centralized RLS Grid component, GridTorrent relies on a Kademlia-based overlay for efficient and scalable Replica Location.