perfsonar client construction

perfSONAR Client ConstructionperfSONAR Client Construction

February 11th 2010, APAN 29 – perfSONAR WorkshopJeff Boote, Assistant Director R&D

• Motivation• Types of Client Interaction

– Echo– MA

• MetadataKeyRequest• SetupDataRequest

– LS• XQuery• Discovery

• API Tour

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Outline

• Development of client applications is crucial to the success of perfSONAR– External applications will consume the measurement data– Researchers will find new users for performance measurements

through client applications• Client development requires knowledge of:

– Service operation– Framework interaction– Available APIs– Data formats

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Motivation

• There are different types of client interaction– Echo Request

• Check the ‘liveness’ of a service

– MA Specific Messages• MetadataKeyRequest

– Request a replayable ‘key’ to get measurement data

• SetupDataRequest– Request measurement data

– LS Specific Messages• Xquery

– Raw interface to LS databaes – using the XQuery interface

• Discovery– Structured discovery queries

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Types of Client Interaction

• The Echo request is a simple message that checks to be sure a service is ‘alive’.

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Echo Request

• Client must be prepared to:– Communicate with services using SOAP over HTTP– Send a request message to a given service URL– Parse the XML response from the service– Record the results of the Echo

• Success in the form of an EchoResponse• Failure in the form of an EchoResponse• Service timeout• Alternate response (anything but an EchoResponse message should

be viewed as a failure)

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Echo Request

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Echo Request

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Echo Request

• The MA derived services have two messages that are interest to client applications:– MetadataKeyRequest

• Given a (partial) metadata description, the service will check if this exists in the database

• If it does exist, return a replayable ‘key’ to have a fast access to measurement data

– SetupDataRequest• Given a (partial) metadata description, the service will check if this

exists in the database• If it does exist, return measurement data

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Measurement Archive

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MetadataKeyRequest

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MetadataKeyRequest

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MetadataKeyRequest

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MetadataKeyRequest

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MetadataKeyRequest

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SetupDataRequest

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SetupDataRequest

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SetupDataRequest

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SetupDataRequest

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SetupDataRequest

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SetupDataRequest

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SetupDataRequest

• Each message has the ability to apply what is called a ‘filter’. • Filters are a way to limit the returned data set:

– By Time– By Type (e.g. in the case of RRD data select which ‘consolidation

function’ is applied)• Filters are applied to a metadata in the message by using the ID

fields

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Measurement Archive

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Measurement Archive - Filtering

• Different measurement archives will have different metadata formats– SNMP MA

• Layer 3 Interface description– perfSONAR BUOY

• Endpoint pair (2 Layer 4 hosts)– PingER

• Endpoint pair (2 Layer 4 hosts)– Status MA

• Layer 3 or Layer 2 Interface description

• Consult the protocol and service documentation for specific formats

• Your client should be prepared to parse the XML to find useful information

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Measurement Archive

• Client must be prepared to:– Communicate with services using SOAP over HTTP– Send a request message to a given service URL– Parse the XML response from the service

• Be prepared to deal with key elements• Understand the data format of the returned measurement data

– In the event of an error:• Interpret a result code from the service• Fail gracefully

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Measurement Archive Requests

• The gLS and hLS have two messages that are interest to client applications:– LSQueryRequest (XQuery Based)

• The metadata subject will contain an XQuery statement• The XQuery will be applied to the Lookup database. • The success or failure will be passed back

– LSQueryRequest (Discovery Based)• A well formed metadata block will contain items to search for

– Domains– Keywords– IP Ranges– Data Types

• The summary database will be consulted• A list of services to consult further (either hLSs or services depending

if you asked at the gLS or hLS layer) will be returned

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Lookup Service

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Lookup Service

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Lookup Service

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Lookup Service

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Lookup Service

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Lookup Service

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Lookup Service

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Lookup Service

• There are several client APIs available in the perfSONAR-PS packages:– perfSONAR_PS::Client::Echo

• Package for performing echo tests against services

– perfSONAR_PS::Client::MA• Package for contacting any MA using general calls

– perfSONAR_PS::Client::PingER• Package for interacting with PingER servers

– perfSONAR_PS::Client::LS• Package for contacting the LS infrastructure, could be used for hLS or

gLS

– perfSONAR_PS::Client::gLS• Package for contacting the gLS infrastructure, could also be used to

contact hLS instances

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API Tour

perfSONAR Client ConstructionperfSONAR Client ConstructionFebruary 11th 2010, APAN 29 – perfSONAR WorkshopJeff Boote, Assistant Director R&D

For more information, visit psps.perfsonar.net

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• Module designed to send a simple EchoRequest to a given service

• Object Oriented• Built in use of:

– SOAP over HTTP transport– XML Parsing– Evaluation of result codes for success or failure

• More information available via perldoc

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perfSONAR_PS::Client::Echo

• Module designed to send a generic MetadataKey/SetupData requests to services


– SOAP over HTTP transport– XML Parsing– Support for error codes

• General construction accepts XML for subjects– Requires that clients have knowledge of the service they are

contacting• Returns XML (metadata and data) in perl objects

– Requires clients to parse out much of the meaning• More information available via perldoc

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perfSONAR_PS::Client::MA

• Module designed to send queries to PingER services• Object Oriented• Built in use of:


• General construction accepts XML for subjects• Returns structured objects that contain data• Used in several GUI applications• More information available via perldoc

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perfSONAR_PS::Client::PingER

• Module designed to query (and perform other operations) on LS type services– Works with gLSs and hLSs



• Main query mechanism is to support arbitrary XQuery statements– Requires knowledge of XQuery to be effective

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perfSONAR_PS::Client::LS

• Module designed to query gLSs, namely the discovery component– Will work on the summary set of an hLS also



• Supports both raw (XQuery type) operation as well as discovery queries:– IP Addresses– Domains– Data Types– Keywords

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perfSONAR_PS::Client::gLS

perfSONAR Client ConstructionperfSONAR Client ConstructionFebruary 11th 2010, APAN 29 – perfSONAR WorkshopJeff Boote, Assistant Director R&D

For more information, visit psps.perfsonar.net

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perfsonar client construction

Documents

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specific formatsyour

measurement dataresearchers

service documentation

request message

different measurement

echoresponse message

simple message