=Paper=
{{Paper
|id=None
|storemode=property
|title=A Linked Data Platform Adapter for the Bugzilla Issue Tracker
|pdfUrl=https://ceur-ws.org/Vol-1272/paper_71.pdf
|volume=Vol-1272
|dblpUrl=https://dblp.org/rec/conf/semweb/MihindukulasooriyaGG14
}}
==A Linked Data Platform Adapter for the Bugzilla Issue Tracker==
https://ceur-ws.org/Vol-1272/paper_71.pdf
A Linked Data Platform adapter
for the Bugzilla issue tracker
Nandana Mihindukulasooriya,
Miguel Esteban-Gutiérrez, and Raúl Garcı́a-Castro
Center for Open Middleware
Ontology Engineering Group, Escuela Técnica Superior de Ingenieros Informáticos
Universidad Politécnica de Madrid, Spain
{nmihindu,mesteban,rgarcia}@fi.upm.es
Abstract. The W3C Linked Data Platform (LDP) specification defines
a standard HTTP-based protocol for read/write Linked Data and pro-
vides the basis for application integration using Linked Data. This paper
presents an LDP adapter for the Bugzilla issue tracker and demonstrates
how to use the LDP protocol to expose a traditional application as a
read/write Linked Data application. This approach provides a flexible
LDP adoption strategy with minimal changes to existing applications.
1 Introduction
The W3C Linked Data Platform (LDP) is an initiative to produce a standard
protocol and a set of best practices for the development of read/write Linked
Data applications [1]. The LDP protocol provides the basis for a novel paradigm
of application integration using Linked Data1 in which each application exposes
its data as a set of Linked Data resources and the application state is driven
following the REST design principles [2].
Some advantages of this approach over traditional SOAP-based web services
include: (a) global identifiers for data that can be accessed using the Web in-
frastructure and typed links between data from different applications [3]; (b) the
graph-based RDF data model that allows consuming and merging data from dif-
ferent sources without having to do complex structural transformations; and (c)
explicit semantics of data expressed in RDF Schema or OWL ontologies which
can be aligned and mapped to data models of other applications using techniques
such as ontology matching.
This approach is more suitable when the integration is data-intensive and the
traceability links between different applications are important. The Application
Lifecycle Management (ALM) domain, in which heterogeneous tools are used
in different phases of the software development lifecycle, provides a good use
case for this approach. The ALM iStack project2 has developed a prototype for
1
http://www.w3.org/DesignIssues/LinkedData.html
2
https://sites.google.com/a/centeropenmiddleware.com/alm-istack/
2 A Linked Data Platform (LDP) Adapter for Bugzilla
integrating ALM tools by using the LDP protocol and this paper presents an
LDP adapter developed to LDP-enable the Bugzilla3 issue tracker.
2 An LDP adapter for Bugzilla
The three main alternatives for LDP-enabling an application are: (a) native
support built into the application; (b) an application plugin; and (c) an LDP
adapter. Providing native support requires modification to the application and
not all applications allow extensions through plugins. As we have seen in the
early stages of web services [4], adapters provide a more flexible mechanism to
gradually adopting a technology while using the existing tools with minimum
changes, and we have leveraged this approach.
An application is defined in terms of its data model and business logic. An
LDP-enabled application exposes the data as Linked Data and allows to drive
its business logic following the REST design principles. Thus to LDP-enable
an application, its data model should be expressed in RDF by mapping it to a
new ontology or by reusing existing vocabularies. In the Bugzilla adapter, the
Bugzilla native data model is mapped to the ALM iStack ontology4 . The adapter
exposes the Bugzilla data as LDP resources by transforming the data between
the ALM iStack ontology and the Bugzilla native model so that LDP clients can
consume RDF data from Bugzilla as if it was a native LDP application.
The Bugzilla LDP adapter, which is a JavaEE web application, consists of
three main layers: (a) LDP layer, (b) transformation layer, and (c) application
gateway layer, as illustrated in Figure 1.
The LDP layer handles the LDP communications and exposes the Bugzilla
data as LDP resources. This layer is built using the LDP4j framework5 which
provides a middleware for the development of read/write Linked Data appli-
cations [5]. The concepts such as bugs, products, product versions, and users
are mapped to LDP containers which list these entities and allow creating new
entities. Each entity such as a bug, a product, or a user is mapped to an LDP
resource with its own URI that can be used by clients to access them.
The transformation layer handles data validation and transformation.
This includes extracting information from RDF data, validating them based
on application restrictions, and mapping them to the Bugzilla model. The ALM
iStack ontology is generic so that it can be used with other issue trackers (e.g.,
JIRA6 , Redmine7 ); thus there is an impedance mismatch between the ontology
and the Bugzilla native model which is managed by the adapter.
The application gateway layer handles the communication with the Bug-
zilla instance using its XML-RPC remote interface. Because the Bugzilla bug
tracker is also accessed using its web UI, the adapter synchronizes with the
3
http://www.bugzilla.org/
4
http://delicias.dia.fi.upm.es/ontologies/alm-istack.owl
5
http://www.ldp4j.org/
6
https://www.atlassian.com/software/jira
7
http://www.redmine.org/
A Linked Data Platform Adapter for Bugzilla 3
Bugzilla instance based on user-defined policies. In addition there are several
cross-cutting services such as configuration management, consistency, security,
and synchronization which are utilized by multiple layers.
Fig. 1. High-level architecture of the Bugzilla adapter
3 Demonstration
This demonstration shows how LDP clients can use the adapter to access the
Bugzilla bug tracker and to perform tasks such as discovering bugs reported
against a product, modifying the status or the other properties of the bug, or
creating new bugs (e.g., Fig. 2 shows a creation request and response).
Fig. 2. Creation of a new bug using the Bugzilla LDP adapter
For example, a continuous integration server in an integrated ALM setting
encounters a build failure. Thus, the “integration server agent” (1) wants to
report a defect (2) titled “Bugzilla adapter build is broken” (3) with descrip-
tion “Bugzilla adapter build fails due to a test failure” (4) for the “version 1.0
4 A Linked Data Platform (LDP) Adapter for Bugzilla
of the Bugzilla Adapter ” product (5) that is related to the “issue 730698 ” in
“https://bugzilla.mozilla.org/ ” (6). The LDP client converts this message to an
LDP request according to the ALM iStack ontology as shown in Figure 2.
Once this request is received by the adapter, it extracts the necessary in-
formation, transforms it into the Bugzilla model using a mapping between the
ontology and Bugzilla models, and creates a bug in the Bugzilla instance using
its remote XML-RPC interface. Once created, the Bugzilla instance returns the
identifier for the bug inside Bugzilla. Then, the adapter generates an URI for
the bug and manages the mapping between the identifier given by the Bugzilla
and the URI. Any information that does not fit into the Bugzilla model such as
links to external applications is maintained in the adapter. Finally, the adapter
returns the URI using the Location header (7) and lets the client know it is an
LDP resource using the “type” link relation (8) according to the LDP protocol.
The LDP client or other external applications can access and link to the bug
using the URI returned by the adapter. In addition, clients can modify the bug
using the PUT operation with modified RDF data which then will be propagated
to the Bugzilla instance following a similar process.
4 Conclusion
In this paper, we presented the Bugzilla LDP adapter and provided an overview
of how to build adapters for LDP-enabling existing applications in order to use
them as read/write Linked Data applications. With minimal changes to the
existing application, the Bugzilla LDP adapter enables semantic integration of
the Bugzilla tool with other LDP-enabled applications and makes possible to
have typed links between application data.
Acknowledgments: The authors are partially supported by the ALM iStack
project of the Center for Open Middleware.
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Candidate Recommendation, http://www.w3.org/TR/ldp/.
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Platform as a novel approach for Enterprise Application Integration. In: Proceed-
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