TU Wien:Advanced Internet Computing VU (Dustdar)/MindMap WS09

Datei:TU Wien-Advanced Internet Computing VU (Dustdar) - MindMap WS09.zip

AIC

• Open World Assumption
• EAI
• SoC
  • Services
    • Standardized Interface / Well-defined - WSDL
    • Self-contained
    • available
    • little integration need
    • granularity
      • fine
      • coarse-grained
    • loosely coupled
    • reusable
    • can be stateful
    • context-independent
    • service-composition
    • QoS
      • measureable
      • availability
      • accessibility
      • integrity
      • performance
    • synchonicity
      • sync RPC-style
      • async message/document-style
  • Interface
    • operations, params, data-typing, access protocols
  • SOA
    • publish/find/bind
    • Roles + grafik
      • Service Providers
      • Service Clients (Requestors)
      • Service Reqistry
    • Technologies
      • Distributed object midware
        • CORBA
        • J2EE
      • Message-oriented midware
        • ActiveMQ
        • IBM WebSphere MQ
      • .. Web services != SOA, = one approach
  • ASP vs Web Services
    • ASP limitations
    • Software as a Service (dazwischen, download)
  • SLAs
    • contract between provider and client
• Web Services
  • do *
    • Describe
      • WSDL
    • Publish
      • UDDI
    • Find
      • UDDI
    • Bind
      • SOAP
    • Invoke
      • SOAP
    • Compose
      • Orchestration (BPEL)
  • Extended Specifications
    • WS-Addressing
    • WS-Policy
    • WS-MetaDataExchange
    • QoS
      • WS-Security
        • integrate kerberos etc
      • WS-ReliableMessaging
        • in-order delivery, at least/most once
      • WS-Coordination
      • WS-Transaction
        • short/long
    • WS-CDL Choreography Description Language
    • BPEL Business Process Exectution Language
• SOAP
  • Simple Object Access Protocoll, XML-based messaging protocol
  • Message Format: Header + Body
  • Roles and processing
    • No nodes
    • All nodes except initial sender
    • Only ultimate receiver
    • + additional roles by modules/application
  • Faults
    • Code, Reason
    • optional: detail, node, role
  • Interaction Styles
    • Document literal
      • binding style="document", soap:body use="literal"
    • Remote procedure call
      • binding style="rpc", soap:body use="encoded"
  • Extensibility
    • features (reliability, security, message exchange patterns)
    • Processing model
    • Protocol bindings
  • Message Exchange Patterns (MEP)
    • features extending one-way communication
    • Request-response
  • Bindings
    • how to use transport protocol
    • HTTP intermediaries != SOAP intermediaries
    • Request-response using HTTP POST
    • Response using HTTP GET
  • Attachments
    • XML Base64 encoding
    • SOAP MTOM (abstract), XOP (impl)
    • MIME for binary parts
• WSDL
  • XML vocabulary to describe Web services
  • exensible and adaptable
  • parts
    • Abstract: operational behaviour (what)
    • Concrete: binding, service (how, where)
  • Abstract
    • Types
      • data type definition (normally XML Schema)
    • Message
      • multiple parts associated with a type
      • RPC -> parts are parameters
    • Operation
      • combinations of input/output
    • Port-type
      • named set of abstract operations
  • WSDL Message Exchange Patterns
    • One-way operation (predefined)
      • async messaging
    • Request-response operation (predefined)
    • Notification operation
      • client has registered for event update
    • Solicit-reponse operation
  • Concrete
    • Bindings
    • Operations
    • Ports
      • individual endpoint, single address
    • Services
      • group of ports, not communicating
      • alternatives for protocol, distance
  • Predefined Bindings
    • SOAP binding
    • HTTP & MIME bindings
  • Problems/Limitations
  • WSDL 2.0
    • simpler, better specified, additional features
    • no message construct
    • interfaces replace port types
    • endpoints replace ports
    • document-style operations first-class-citizens
    • MEPs
      • message exchange patterns more flexible
      • faults as interace sub-elements
      • 8 predefined
        • in-only, out-only
        • robust in-only, robust-out-only
        • in-out, out-in
        • in-optional-out, out-optional-in
    • interface extensions / fault extensions
    • import / include ... different/same target namespace
    • WSDL 1.1 widely used, WSDL 2.0 adoption takes time
• Web service Composition
  • Business processes
    • activity performed in sequence according to business rules, produces outcome
    • short/long lived
    • internally or between business partners
    • Process model - real world
    • Workflow model - technology interactions
  • Requirements
    • Combine and link existing Web services
    • Flexible, Recursive, Recoverable, Seperation of concerns
  • Issues
    • Abstract process representation
    • Discovery and interoperability
    • Efficiency
    • Process Execution and Monitoring
  • Orchestration vs Choreography
    • Orchestration
      • "part-of" sense
      • compose web services for business processes
      • define composite services
      • reuse of existing web services
    • Choreography
      • "sequencing" sense
      • compose web services for business collaboration
      • peer-to-peer model
      • define how multiple parties collaborate
  • Web services workflows
    • thousands of Web services available
    • requires analysis of web services QoS
  • Composition
    • multi-party conversational interactions
    • approaches
      • process-based
      • requirements-driven
      • AI-based
    • protocols
      • Orchestration (BPEL)
      • Cheoreography (WS-CDL)
      • Event-based federation (WS-Eventing)
    • time
      • design time (static composition)
      • deployment time ... e.g. different services per installation
      • run time (dynamic composition)
    • dynamic issues
      • discovery, QoS parameter negotionation
      • services do not answer, wrong state info, service contract violation
      • service protocols and policies
  • Research
    • Autonomic composition
      • self-configuring
        • discovery
      • self-optimizing
        • selection
      • self-healing
        • reaction
      • self-adapting
        • behaviour-change
    • QoS-aware service compositions
      • respect policies, performance levels,security requirements, SLAs,...
  • WS-BPEL
    • Web Services Business Process Execution Language
    • Process-oriented composition language
    • concrete vs abstract processes
    • mainly orchestration, some choreography support
    • WSDL-based, block-structured
    • Activities - primitive/structured
    • Data handling - containers
    • Processes
      • Abstract
        • may hide optional details
        • describe externally visible interactions
      • Concrete
        • implementation details
        • internal business logic
    • Service Selection
      • Partner Link Type
      • Partner Link
      • Endpoint
    • Binding
      • static/dynamic
    • Adoption/Implementations
      • Apache ODE
      • WebSphere
      • Biztalk erver
      • OraceBPEL
  • WS-CDL
    • Web Services Choreography Description Language
    • Declarative language for B2B interaction patterns
    • Global definition formessage exchanges
      • Ordering conditions
      • Constraints
    • Complementary to WS-BPEL
      • extends choreography support
      • more global view
      • declarative, not executeable
    • hardly adopted, over-engineered and too abstract
• Transactions
  • Intro
    • QoS-Layer: WS-C, WS-AT, WS-BA
    • Two-phase commit (2PC)
      • prepare, commit
    • Resource locking
    • ACID Properties
    • Atomicity + Consistency + Isolation + Durability
  • WS-Transactions challenges
    • loose coupling
    • distribution
    • heterogeneity
    • long runtimes
  • Long-running activities
    • commit sub-activities on completion
    • error -> rollback, compensation
    • application specific compensation
    • limited isolation, visible intermediary results
  • Coordination / WS-TransactionStandards
    • About
      • example: auction + trading / bidding
      • Protocols
        • message exchange between participant and coordinator
      • Coordinator
        • mediates, agreement protocols
      • Participants
        • must agree on outcome
        • plays one-to-many roles (completer, 2PC resource manager, caching...)
      • Activities
        • combine distributed web services
    • WS-Coordination
      • Foundation layer for coordination
      • Activation, Registration
      • Coordination context
      • Extensibility
    • WS-AtomicTransaction
      • 2-phase commit for web services (2PC)
      • short-lived activities
    • WS-BusinessActivity
      • long-running transactions
      • operation nesting
      • compensation-based
      • combine with atomic transactions
• WS Metadata UDDI
  • Metadata
    • addressing information for endpoint
    • required extended features
    • QoS attributes
  • Technologies
    • XML Schema
      • data types
    • WSDL
      • messages, interfaces, endpoints
      • message exchange patterns
    • WS-Addressing
      • web service endpoint references
    • WS-Policy
      • QoS requirements
    • UDDI
      • metadata repository
    • WS-MetadataExchange
      • dynamic metadata exchange
  • UBR
    • Universal Business Registry
    • global registry of all services
    • quality issues, availability of services...
    • > mainly private/semi-private UDDIs
  • UDDI
    • Universal Description, Discovery and Integration
    • APIs in WSDL with SOAP binding to publish & query
    • purspose: web service info & dynamic binding
    • Registry
      • White pages: business information
      • Yellow pages: categorization
      • Green pages: technical information
    • Data
      • businessEntity
        • organization
        • contact info
      • businessService
        • web services
        • addresses, versions, protocols, ..
      • bindingTemplate
        • technical manual
        • parameters, default values, ...
      • tModel
        • generic container spec
          • WSDL specification
        • reference to actual document
        • unstrctured, human-readable
    • Dynamic binding
      • standard interface as tModel
      • app queries UDDI for known tModel key
  • WS-Addressing
    • Motivation
      • messaging
        • BPEL
      • coordination/transactions
      • no addressing in SOAP
      • transport-protocol independence required
    • Specifies
      • endpoint references
      • additional SOAP headers
    • Endpoint References
      • map to WSDL port
      • Address URI
      • Reference Property
      • Reference Parameter
      • optional Metadata (port type, policies, ...)
    • Message Headers
      • mandatory: To, Action
      • optional: related endpoints, msg relationships
  • WS-Policy
    • describe nonfunctional service behaviour (vs WSDL)
    • eg: supports/requires transactions, security, QoS
    • WS-Policy (define) + WS-PolicyAttachment (apply)
    • Policy
      • assertions + operators
      • ExactlyOne, All, optional attribute
    • Normal Form for intersection: ExactlyOne + Alls
    • Validation using intersection + domain-specific knowledge
  • WS-MetadataExchange
    • WSDL interface for metadata exchange between endpoints
    • Bootstrapping of interactions
    • Extensibility + Redirection
• WS-I
  • WS-I Basic Profile
  • subset of proven, interoperable WS features
  • checklist for middleware providers
  • WS-I Basic Security Profile
• REST
  • Representational State Transfer
  • architectural style for distributed systems
  • basic architecture of the WWW
    • HTTP & URI
  • simple, ad-hoc, light-weight
  • Characteristics
    • Resource-Orientation
      • MIME-type
    • Statelessness
      • so is HTTP
    • Uniform Interface
      • HTTP interface, GET POST PUT HEAD DELETE
    • Naming
      • unique and descriptive
      • URI per resource
    • Layering
      • transparent intermediaries (proxies, caches)
      • supported by HTTP
  • RESTful Web Services
    • in line with the Web
    • HTTP + URI
    • XML or JSON, HTML, ...
    • JAX-RS
      • Java API
      • POJO based
      • annotations
      • Jersey, Apache CXF, JBoss Resteasy
• SOAP vs REST
  • SOAP & WS-*
    • + protocol transparent
    • + wsdl
    • - fuzzy boundaries
    • performance
  • RESTful
    • + simple & lightweight, HTTP, XML, URI, MIME
    • + HTTP available in languages/platforms
    • + port 80 - firewalls
    • - Hi-REST vs Lo-REST
• Mashups
  • eg: netvibes
  • ad-hoc
  • client-side / server-side
  • JSON, RSS, Atom
  • Service Mashups
    • combine services with
      • fresh content
      • collaborative approaches (tags)
      • semantic techs (RSS, RDFa, SPARQL)
    • often RESTful
    • Tools
      • Yahoo Pipes
• Research Questions
  • Autonomic Management