Introduction to Access Grid Development

Access Grid Workshop – APAC ‘05

Introduction to Access Grid Development

Access Grid Workshop – APAC ‘05

Agenda

• Architecture• AG Application Basics• AccessGrid module overview• Example application• Exercises

Access Grid Workshop – APAC ‘05

Architecture

Access Grid Workshop – APAC ‘05

Technologies

• Python• wxPython• pyGlobus• SOAP (SOAPpy)• pyOpenSSL

Access Grid Workshop – APAC ‘05

AG Application Basics

An Access Grid client application will perform (at least) these steps:

• Create an application instance• Initialize application • Create an interface wrapper• Call methods on the interface

wrapper

Access Grid Workshop – APAC ‘05

AG Application Basics

• The core of an AG application is an instance of AccessGrid.Toolkit.Application

AppBase

Application

CmdlineApplication WXGUIApplication

Service

Access Grid Workshop – APAC ‘05

AG Application Basics

• Distinguished between GUI and non-GUI applications to generalize user interactions (for example, prompt for passphrase, error reporting)– CmdlineApplication

• Examples: BridgeServer, VenueServer, AGNodeService

– WXGUIApplication• Examples: VenueClient,

VenueManagement, NodeManagement

Access Grid Workshop – APAC ‘05

Application Initialization

• Create AG application instance• Initialize application

– Verify certificate repository– Load default certificate– Create proxy certificate– Configure Globus environment

app = CmdlineApplication.instance()app.Initialize(appName)

• appName is used in logfile name

Access Grid Workshop – APAC ‘05

Argument Processing

• Standard Python module optparse is integrated into toolkit

• Add option to application before initialization

• Access options post-initialization

app.AddCmdLineOption(optparse.Option(‘-u’,’—url’,

dest=‘url’))

app.Initialize(‘SampleApp’)

url = app.GetOption(‘url’)

Access Grid Workshop – APAC ‘05

Standard Toolkit Arguments

• The toolkit adds some options to all applications

• Available options can be viewed with ‘-h’ or –help

• Examples-d (turn on debug)-l <logFileName>--logfilesize <size> --numlogfiles <num> (rollover log files)

Access Grid Workshop – APAC ‘05

Logging

• Standard Python module logging is integrated into AccessGrid toolkit

• Multiple logging levels are defined (see logging module documentation)– CRITICAL, ERROR, WARNING, INFO, DEBUG

• Logging levels can be controlled for individual components in an application

• Application will create appName.log (appName is from app.Initialize) in Log directory:– Windows: %APPDATA%\AccessGrid\Logs– Linux/OSX: $HOME/.AccessGrid/Logs

• Logging calls in code will appear in logfile, according to call and current logging level– log.debug(‘this is debug logging text’)

Access Grid Workshop – APAC ‘05

AccessGrid Module Overview

• AccessGrid– Core toolkit code

• AccessGrid.Security– CertificateManager, CertificateRepository, etc.– AuthorizationManager, Role, Action, etc.

• AccessGrid.Platform– Platform-specific code

• Config.{SystemConfig,UserConfig,etc.}• ProcessManager

• AccessGrid.hosting– SOAP implementation adapters

Access Grid Workshop – APAC ‘05

AccessGrid Module API Documentation

Access Grid Workshop – APAC ‘05

Interfaces and InterfaceWrappers

• Described in online API documentation• Interface wrappers are defined in

individual modules– For example, AccessGrid.Venue.VenueIW

• IW (and I) class methods handle serialization/deserialization of data types from SOAP implementation domain to AG application domain

Access Grid Workshop – APAC ‘05

Available InterfaceWrappers

• VenueIW• VenueServerIW• VenueClientIW• AGNodeServiceIW• AGServiceManagerIW• AGServiceIW• AuthorizationManagerIW• SharedApplicationIW• NetworkServiceIW

Access Grid Workshop – APAC ‘05

VenueIW

Access Grid Workshop – APAC ‘05

Types

• Many types are found in Descriptions.py– StreamDescription– ApplicationDescription

• Others are found in their own modules– ClientProfile– AGParameter– Capability

Access Grid Workshop – APAC ‘05

AG Applications

An Access Grid client application will perform (at least) these steps:

• Create an application instance• Initialize application • Create an interface wrapper• Call methods on the interface

wrapper

Access Grid Workshop – APAC ‘05

Example: GetClients.py

#!/usr/bin/python2

import sysfrom AccessGrid.Toolkit import CmdlineApplicationfrom AccessGrid.Venue import VenueIW

url = sys.argv[1]

# Create and initialize applicationapp = CmdlineApplication()app.Initialize('qwe')# Create venue interface wrappervenue = VenueIW(url)

# Get clients from venue and processclientList = venue.GetClients()for client in clientList: print client

Access Grid Workshop – APAC ‘05

Example: GetClients.py

python GetClients.py https://vv2.mcs.anl.gov:9000/Venues/default

Profile Type: userName: Tom UramEmail: [email protected] Number: Location: Chicago, ILVenue Client URL:

https://wormtongue.mcs.anl.gov:11000/VenueClientPublic ID: 00000102220e6208008c00dd0022004754dHome Venue:

https://vv2.mcs.anl.gov:9000/Venues/default

Access Grid Workshop – APAC ‘05

Example: GetClients.py

• Check logfile GetClients.log

Access Grid Workshop – APAC ‘05

Notes

• Online workshop materials:http://www.mcs.anl.gov/fl/research/accessgrid/documentation/tutorial/AGTk_2.4

• Online developer documentation (including API reference):

http://www.mcs.anl.gov/fl/research/accessgrid/software/developer.html

• OSX users will need to source an environment file to run code in a terminal– /Applications/AccessGridToolkit.app/Contents/

Resources/setupenv.sh

Access Grid Workshop – APAC ‘05

Exercise: GetStreams.py

• Modify GetClients.py to call GetStreams instead of GetClients

• Return value is a list of Descriptions.StreamDescription

Access Grid Workshop – APAC ‘05

Exercise: GetUsers.py

• Modify GetClients.py to call VenueClientIW.GetUsers

• Return value is a list of ClientProfile

Access Grid Workshop – APAC ‘05

Access Grid Workshop – APAC ‘05