Globus C Web Services Core for Developers

1
Globus C Web Services Corefor Developers

• Bill Allcock, ANL
• Joe Bester, ANL
• GlobusWORLD / GridWORLD
• Sep 2006

2
Features

• Hosting web services written in C and C
• Implementation of WSRF concepts and port types
• Type, client, and service bindings generator from
  WSDL and XML schemas to C
• Client APIs and programs

3
Service Engine/Container

• API (globus_service_engine) for processing WS
  requests within an application
• Uses HTTP processor in XIO
• SOAP serializer/deserializer
• Service loading and invocation
• Program for hosting services
• globus-wsc-container

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Service Engine Usage

• globus_service_engine_init()
• To manage connection usage
• globus_service_engine_register_session(),globus_s
  ervice_engine_register_process()
• For simplicity
• globus_service_engine_register_start(),globus_ser
  vice_engine_register_stop()

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WS-Resources

• Resource management API
• create/find/destroy resource
• property management
• lifetime management
• globus_wsrf_core_tools.h includes function to
  find resource from EPR used in the current message

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WS-Resource Properties

• Property values associated with a type_info for
  serialization information
• Property values may be dynamic
• callbacks for attempts to get or set the value
• Apps can be notified when properties change
• Call globus_resource_property_changed() for
  dynamic values

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Operation Providers

• Reuse a port type implementation
• Resource Properties
• Operations
• Examples
• wsrpGetResourceProperty
• GetResourceProperty operation
• wsrlScheduledResourceTermination
• SetTerminationTime operation
• CurrentTime, TerminationTime properties

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Notification Consumer

• Callback-driven notification
• User has to deal with XML wildcard messages
• Usage
• Create Engine (don't forget to start it!)
• Create Consumer
• Returns EPR of Notification Consumer Service
• Subscribe via client stubs
• May be different for some services

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Notification Producer

• wsntNotificationProducer provider
• Creates notification-related properties
• Handles Subscribe/GetCurrentMessage operations
• Creates Topics for Resource Properties
• Notification Producer API
• Create/destroy topics
• Change topics
• Also manage producer, subscriptions, etc
• but provider handles these for you

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Service Groups

• wssgServiceGroup, wssgServiceGroupRegistration
  providers
• creates wssg-related properties (Entry,
  MembershipContentRule)
• implements Add operation
• service_group API to manage entries
• add/remove entries
• enumerate entries
• also create/destroy service group
• provider handles these for you

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Handler Chains

• Handle specific message elements
• Called when matching header element is found
• Examples
• WS-Addressing
• Set attributes when addressing values encountered
• Verify all required addressing elements are
  present
• WS-SecureMessage
• Add attributes for elements to be signed
• Add message signatures

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SOAP Messaging

• XML Serialization Handles
• to/from file, memory, libxml DOM, HTTP
• Options to control (de)serialization
• default NS
• xsitype attribute
• c14n

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Message Attributes

• Key-Value pairs
• When value is set, optional copy and destroy
  functions for memory management
• Default attributes set at engine initialization
  (service) or on a client stub
• Additional attributes used to pass info from
  message handlers
• Example wsaTo value set by WS-Addressing handler

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Message Attributes (2)

• Authentication Options
• TLS / WS-SecureMessage
• Credentials to use
• Message protection
• Peer subject name
• Also Message timeouts, persistent connections

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Bindings Generator

• globus-wsrf-cgen program
• Uses JavaScript-based template language
• Generates type bindings
• Data structures, allocators, deallocators,
  serializers, etc
• Type information for wildcard handling
• Generates service module to call service
  implementation
• Generates client stub functions to invoke
  (remote) operations
• Generates Packaging/Makefiles

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Resource Property Element

• ltelement name"CounterRP"gt
• ltcomplexTypegt
• ltsequencegt
• ltelement ref"tnsValue"/gt
• ltelement maxOccurs"unbounded"
  ref"rpns0Topic"/gt
• ltelement maxOccurs"unbounded"
• ref"rpns0TopicExpressionDia
  lects"/gt
• ltelement ref"rpns1TerminationTime"/gt
• ltelement ref"rpns1CurrentTime"/gt
• ltelement ref"rpns0FixedTopicSet"/gt
• lt/sequencegt
• lt/complexTypegt
• lt/elementgt

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Example Counter Service

• ltelement name"createCounter"gt
• ltcomplexType/gt
• lt/elementgt
• ltelement name"createCounterResponse"gt
• ltcomplexTypegt
• ltsequencegt
• ltelement ref"wsaEndpointReference"/gt
• lt/sequencegt
• lt/complexTypegt
• lt/elementgt

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Message Definition

• ltmessage name"CreateCounterRequest"gt
• ltpart name"request"
• element"tnscreateCounter"/gt
• lt/messagegt
• ltmessage name"CreateCounterResponse"gt
• ltpart name"response"
• element"tnscreateCounterResponse"/gt
• lt/messagegt

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Port Type Definition

• ltportType name"CounterPortType"
• wsrpResourceProperties"tnsCounterRP"gt
• ltoperation name"createCounter"gt
• ltinput
• message"tnsCreateCounterRequest"/gt
• ltoutput
• message"tnsCreateCounterResponse"/gt
• lt/operationgt
• ...
• lt/portTypegt

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C Type Binding

• typedef struct createCounterResponseType_s
• wsa_EndpointReferenceType EndpointReference
• createCounterResponseType
• typedef struct createCounterResponseType_array_s
• struct createCounterResponseType_s
• elements
• int length
• globus_xsd_type_info_t type_info
• createCounterType_array

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C Type Bindings Functions

• globus_result_t
• createCounterResponseType_init(
• createCounterResponseType inst)
• void
• createCounterResponseType_destroy(
• createCounterResponseType inst)
• struct createCounterType_s
• createCounterResponseType_array_push(
• createCounterResponseType_array array)

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C Type Serializer

• globus_result_t
• createCounterResponseType_serialize(
• const xsd_QName element_name,
• const createCounterResponseType val,
• globus_soap_message_handle_t message_handle,
• globus_xsd_element_options_t options)
• also deserialize, copy, array, contents-only
  versions.

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XML Wildcards (1)

• struct globus_xsd_type_info_s
• xsd_QName type
• globus_xsd_serialize_func_t serialize
• globus_xsd_deserialize_func_t deserialize
• globus_xsd_init_func_t initialize
• globus_xsd_destroy_func_t destroy
• globus_xsd_copy_func_t copy
• ...

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XML Wildcards (2)

• typedef struct xsd_any_s
• globus_xsd_type_registry_t registry
• globus_xsd_type_info_t any_info
• xsd_QName element
• void value
• xsd_string_array
  namespaces
• xsd_any

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Client Stub Binding

• globus_result_t
• CounterPortType_createCounter(
• CounterService_client_handle_t handle,
• const char service_endpoint,
• const createCounterType createCounter,
• createCounterResponseType
• createCounterResponse,
• CounterPortType_createCounter_fault_t
• fault_type,
• xsd_any fault)
• Also with EPR in place of service_endpoint
• Also non-blocking functions
• Request and response versions

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Client Example (1)

• createCounterType createCounter
• createCounterResponseType createCounterResponseN
  ULL
• createCounterType_init_contents(createCounter)
• globus_soap_message_attr_init(attrs)
• globus_soap_message_attr_set(
• attrs,
• GLOBUS_SOAP_MESSAGE_AUTHENTICATION_METHOD_KEY,
  
• NULL, NULL,
• GLOBUS_SOAP_MESSAGE_AUTH_SECURE_MESSAGE)
• CounterService_client_init(
• client_handle, attrs, NULL)

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Client Example (2)

• result CounterPortType_createCounter(
• client_handle,
• counter_service_contact,
• createCounter,
• createCounterResponse,
• fault_type,
• fault)
• if (result ! GLOBUS_SUCCESS) ...
• globus_wsrf_core_export_endpoint_reference(
• createCounterResponse-gtEndpointReference,
  
• "counter.epr",
• wsa_EndpointReference_qname)l

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Service Initialization

• globus_result_t
• CounterService_init(
• globus_service_descriptor_t service_desc)
• globus_module_activate(
• GLOBUS_WSRF_RESOURCE_MODULE)
• ...

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Operation Implementation

• globus_result_t
• CounterPortType_createCounter_impl(
• globus_service_engine_t engine,
• globus_soap_message_handle_t message,
• globus_service_descriptor_t service,
• createCounterType createCounter,
• createCounterResponseType
• createCounterResponse,
• const char fault_name,
• void fault)

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Service EPR Construction

• globus_service_engine_get_contact(
• engine, endpoint)
• epr-gtAddress.base_value
• globus_common_create_string("s/s",
• endpoint,COUNTERSERVICE_BASE_PATH)
• counter_key xsd_any_array_push(
• epr-gtReferenceProperties-gtany)
• counter_key-gtany_info xsd_string_info
• counter_key-gtelement CounterKey_qname
• counter_key-gtvalue resource_id

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add operation

• globus_result_t
• CounterPortType_add_impl(
• globus_service_engine_t engine,
• globus_soap_message_handle_t message,
• globus_service_descriptor_t service,
• xsd_int add,
• xsd_int addResponse,
• const char fault_name,
• void fault)

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add implementation

• globus_wsrf_core_get_resource(
• message, service, resource)
• globus_resource_get_property(resource,
• CounterPortType_Value_rp_qname,
• (void )counter_value, NULL)
• counter_value add
• addResponse counter_value
• globus_resource_property_changed(resource,
  CounterPortType_Value_rp_qname)
• globus_resource_finish(resource)

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Generating WSRF Faults

• time_t timestamp time(NULL)
• wsrp_ResourceUnknownFaultType_init(fault)
• globus_libc_gmtime_r(timestamp,
• (fault)-gtTimestamp)
• fault_name"ResourceUnknownFault"

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Performance Snapshot (GT 4.0.1)
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Use Case globusrun-ws

• Command-line client to submit and monitor WS-GRAM
  jobs
• Interacts with WS-Delegation, WS-GRAM, and
  (indirectly) RFT
• Includes a service engine to handle notification
  messages from WS-GRAM
• On the order of 20x faster than the Java client
  program
• Largely due to the JVM startup costs

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Use Case RFT Client

• Command-line client to RFT service
• RFT performs reliable 3rd-party transfers using
  GridFTP
• Create a transfer, start monitor it
• Monitoring via WS-Notification
• Adds features, improves performance over previous
  java client
• Meet Ravi
• 9/14 1130 AM "Globus RFT for Developers"

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Use Case GridFTP Resource Properties

• Experimental GridFTP feature
• Server exposes state via resource properties
• Server load
• Connection limits
• Acts as WS-MDS provider

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Use Case Container on an ARM processor

• Prototype for ocean floor sensor platform for the
  LOOKING project
• Port of C WS Core to proprietary embedded
  operating system
• Development board with 4MB Flash, 16MB RAM
• NETOS
• C Container statically linked with OS and services

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Use Case Core Command-Line tools

• Substitute for Java CLI tools in 4.1, 4.2
• Clients work with any service implementing the
  related port types
• WS-ResourceProperties
• globus-wsrf-query
• globus-wsrf-get-property
• globus-wsrf-get-properties
• globus-wsrf-insert-property
• globus-wsrf-update-property
• globus-wsrf-delete-property

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Use Case Core Command-Line tools

• WS-ResourceLifetime
• globus-wsrf-destroy
• globus-wsrf-set-termination-time
• WS-BaseNotification
• globus-wsn-get-current-message
• globus-wsn-pause-subscription
• globus-wsn-resume-subscription
• globus-wsn-subscribe

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Project Web Page / Contributions

• http//dev.globus.org/wiki/C_WS_Core
• Globus is largely following the Apache project
  model at this point.
• We would welcome contributors.
• Long term, high quality contributors can be voted
  in as committers.
• An alternative would be to start a new,
  independent project that utilized C WS Core, on
  which you could be a committer at the start.

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Getting help / more information

• Email lists
• cwscore-devuserannounce_at_globus.org
• Documentation
• http//www.globus.org/toolkit/docs
• Bugzilla
• http//bugzilla.globus.org/bugzilla
• Product is C WS Core
• HPDC Paper
• http//www.globus.org/alliance/publications/papers
  /WSRFComparison2005-3.pdf
• Comparison of five different WSRF implementations

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Futures

• More clients (delegation, ...)
• Improved container
• More core services (registry, secure
  conversation, )
• More flexible container configuration
• Authorization Improvements
• Persistent services
• Update to newer web standards
• Your C based Web service or client?

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Meet the Developers Session at Globus Alliance
Booth (152A-P7)

• September 12800am - 900am "Java WS Core and
  Security (C, Java)"  -- Olle Mulmo, Jarek Gawor,
  Rachana Anantakrishnan
• 1130am -1230pm "RLS" -- Rob Schuler, Ann
  Chervenak1230pm -130pm "MDS" -- Mike D'arcy,
  Laura Pearlman300pm - 400pm Resource
  Management (GRAM, Virtual Workspaces and Dynamic
  Accounts)" Stu Martin, Peter Lane, Tim Freeman,
  Kate Keahey600pm - 700pm "C WS Core" -- Joe
  Bester700pm - 800pm "Python WS Core" -- Joshua
  Boverhof
• September 13800am - 900am "GridShib" -- Von
  Welch, Ton Scavo, Tim Freeman
• 1130am - 1230pm "GT Installation and
  Administration" -- Charles Bacon1230pm - 130pm
  "MyProxy" -- Jim Basney300pm - 400pm "GridFTP,
  XIO, RFT" -- John Bresnahan, Ravi Madduri

45
Question Do you see a Fun Exciting Career in
my future? Magic 8 Ball All Signs Point to YES

• Say YES to Great Career Opportunities
• SOFTWARE ENGINEER/ARCHITECT
• Mathematics and Computer Science Division,
  Argonne National Laboratory
• The Grid is one of today's hottest technologies,
  and our team in the Distributed Systems
  Laboratory (www.mcs.anl.gov/dsl) is at the heart
  of it. Send us a resume through the Argonne site
  (www.anl.gov/Careers/), requisition number
  MCS-310886.
• SOFTWARE DEVELOPERS Computation Institute,
  University of Chicago
• Join a world-class team developing pioneering
  eScience technologies and applications. Apply
  using the University's online employment
  application (http//jobs.uchicago.edu/, click
  "Job Opportunities" and search for requisition
  numbers 072817 and 072442).
• See our Posting on the GlobusWorld Job Board or
  Talk to Any of our Globus Folks.