The WatG Browser (What is at the Grid
Browser) is a web-based Grid Information System (GIS)
visualization application providing detailed overview of the
status and availability of various Grid resources in a given
gLite-based e-Infrastructure. It is able to query and present
data obtained from Grid information systems at different layers:
from local resource information system for a particular Grid
service (GRIS), to the Grid site information system (site BDII),
and to the top-level information system for the whole Grid
infrastructure (top-level BDII). |
The efficient implementation of WatG Browser
allows quick and easy navigation through entries and objects of
the LDAP tree retrieved by the specified query, even if the size
of the output is huge and hierarchically very complex. Highly
responsibility is achieved with implementation of partial
refreshes and asynchonization of a web page. A partial refresh
of WatG application can be observed when an interaction event is
triggered, for example click on the plus icon of the LDAP tree.
The server processes the information and returns a limited
response specific to the data it receives, for example LDAP's
subtree that requires given condition. One may notice that WatG
server does not send back an entire page, like the conventional
"click, wait and refresh" web applications. Instead, WatG client
updates the page based on the response. This means that only
part of the page is updated. In other words, WatG's initial page
is treated like a template: WatG server and client exchange the
data and the client updates parts of the template based on the
data it receives from the server. Another way to think about it
is to consider WatG application as driven by events and data,
whereas conventional web applications are driven by pages.
Asynchronization of the WatG application is reflected in the
fact that after sending data to the server, the client can
continue processing while the server does its processing in the
background. During all this, a user can continue interacting
with the client without noticing interruption or a lag in the
response. For example, a user can click on any plus or minus
icon even during the loading, and in that way a new request will
be created and executed afterwards. The client does not have to
wait for a response from the server before continuing, as is the
case in the traditional, synchronous approach. Architecture of
the WatG Browser is given below.
The above main features of WatG
application introduce also many secondary ones. For example, a
partial refresh hides huge complexity and amount of data stored
in a Grid Information System, which have to be transferred from
the server to the client. Therefore, WatG is able to browse
large LDAP directories keeping out of sight its nontrivial
structure and size.
Current WatG front-end performs a search
using the filter. Search filters enable defining search criteria
and provide more efficient and effective searches. The filter
should conform to the string representation for LDAP filters.
The WaiG front-end also contains attribute field, which returns
only selected entries and values if specified. |
Nov 2011 - WatG Browser at EGI AppDB [URL]
Sep 2011 - WatG Browser at EGI TF 2011 conference [PDF]
Mar 2011 - WatG Browser in Journal of Grid Computing [PDF]
Dec 2009 - WatG Browser at SEE-GRID-SCI User Forum [PDF]
Sep 2009 - WatG Browser poster at EGEE'09 conference [PDF]
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