Composite Services

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Composite Services

• Gustavo Alonso
• Swiss Federal Institute of Technology (ETHZ)
• Zürich, Switzerland

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Outline

• Our vision and grand goals
• State of the art and influence on ADAPT
• Progress so far
• Work on year two

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Our vision

• Automating the integration of IT infrastructures
  through Web service composition, business
  protocols, and conversation specifications

Service specification
Automated validation of the composition
Enactment
Automatic extraction of service data
Automated support for composition
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Our grand goals

• Through automation and leveraging Web services we
  hope to
• reduce the development cost of B2B applications
• make Web service technology available to SMEs
• create the basics for plugplay Web service
  technology
• complement standardization in areas that are
  currently not being well covered by industry
  efforts
• hide the complexity and changing nature of Web
  service technology from the end user
• contribute to standardization efforts in
  composite services
• open source platform

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State of the art

• Many important developments in the last year
• BPEL specification
• BPEL implementations (Collaxa, BPELWS4j)
• Many additional specifications relevant to
  composition (WS-CAF, WSIF, WS-Coordination,
  WS-Transactions, Grid, etc.)
• Many changes and not a clear direction
• Competing standards without a clear winner
  (ebXML, xCBL)
• Luckily, this situation does not negatively
  influence our plans within ADAPT (so far, we will
  keep a close watch)
• our goals still beyond the scope of industry
  efforts
• we profit from all the tools that have become
  available

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Influences on ADAPT

• CONCEPTUAL DESIGN
• Use of Web service specifications is ill defined
  and changing
• The range of design options is widening and may
  require us to focus on a particular application
  type
• The focus is also shifting in industry (from
  simple services to conversations)

• ACTUAL ARCHITECTURE
• Increasing number of tools available (to enhance
  the work on ADAPT, or to give us a link to
  products)
• May have to postpone some design decisions until
  a later stage than planned
• Otherwise, the initial goals of the ADAPT
  platform for composition remain unchanged

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Progress so far

• Two prototype composition engines (based on
  previous work) capable of automatically importing
  information about Web services (WSDL
  description), embedding the operations within a
  workflow process, and invoking the services using
  SOAP
• Centralized engine (Java)
• Distributed engine (Java)
• Bottom up composition
• Graphical tool for composition
• Consensus formed on model behind composition (Pi
  calculus) and properties of composition that we
  will support (transactions, choreography).

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Evaluation of progress so far

• All the background work has been done
• thorough understanding of available technology
• flexible design to keep our options open
  (centralized, distributed, bottom up
  composition, top down composition, conversation
  based composition, etc.)
• Existing prototypes provide excellent platform
  for experimentation and exploring interaction of
  heterogeneous systems
• Consensus emerging on what are the limits to what
  we can do in ADAPT, what we can take from others
  (e.g., TAPAS), and where the strength of the open
  source platform will be

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Planned work for year two

• Consolidation of the prototypes
• possible decision to go with only one engine (not
  necessary)
• Closer look at top down composition (as an
  extension or alternative)
• Tying together of graphical tool, engines and
  composition model in a single unified framework
• careful attention to standards (BPEL)
• Work on adaptive composition and automated
  analysis
• transactions
• choreography and business protocols
• First version of the ADAPT platform

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http//www.iks.ethz.ch/jopera
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JOpera Architecture
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JOpera Distributed Kernel
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JOpera Storage Architecture
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Cost of persistent storage
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Process instantiation time
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Throughput degradation
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Scalability (Response time)
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Scalability (throughput)
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Split/Merge Options
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Reliable WS Call

• Static Dynamic

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Visual XML Transformation
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WS Demo Process
This process is included as an example of WS
composition with the current JOpera release