GCF Primer

1. Tutorial overview
   1. Ground rules: preparing the environment
   2. Obtaining and running gCore
2. From configuration to testing with a single Port-Type
   1. Structuring the service code
   2. Delving into the implementation
   3. Building & Deploying
   4. gCore Logging & Restart
   5. A Test Client
   6. Refining the implementation
3. Adding State
   1. Multi Port-Type service
   2. Basic steps
   3. Implementation
   4. Configuring JNDIs & Descriptors
   5. Building & Deploying
   6. A Test Client
4. Learning more

Tutorial overview

This tutorial intends to present gCore and its related software required to design, build, and deploy software that can be effectively used to build complex applications that might be eventually integrated within a gCube infrastructure.

How this tutorial is organized

The tutorial takes an incremental approach to illustrate all the steps of the service development cycle in relation to a first Port-Type. For simplicity, it assumes the Port-Type to be stateless. Then it introduces the assumption of state, when by enriching the sample service with additional Port-Types.

Who should use this tutorial

gCore Tutorial is dedicated to developers that have an average knowledge of Unix-like systems and Java, and some experience with Web Service concepts, terminology, and procedures. The purpose of the tutorial is to help them take advantage of the numerous patterns, interfaces, frameworks, and tools offered by the gCore framework creating well-structured and supported gCube services.

Ground rules: preparing the environment

• Exclusively a Java & Unix-like system environment
  • JDK 1.5.0_08+
  • OS requirements as per underlying Globus
• Typically, a Shell + IDE environment
  • IDE for code configuration & authoring
  • Shell for code building & deployment
  • Require both installation & configuration

Obtaining and running gCore

• through SVN checkout

https://svn.research-infrastructures.eu/gcore/gcore/trunk/GCORE/CONTAINER

• with Etics downloads (only for gCube developers)

https://grids16.eng.it/BuildReport/, Module: org.gcore.gcontainer

• through command line or IDE plugin alike, e.g. Subversion for Eclipse

Put it into a folder of choice (named from now on, the gCore LOCATION)

gCore at a glance

Here is the directory structure once the gCore distribution is uncompressed

gCore LOCATION
|
|-bin
|
|-config
|
|-endorsed
|
|-etc
|
|-lib
|
|-libexec
|
|-share
       |
       |-gcore_tools
       |-globus_wsrf_common
       |-globus_wsrf_core
       |-globus_wsrf_core_registry
       |-globus_wsrf_msd_userful_rp_schema
       |-globus_wsrf_test
       |-globus_wsrf_tools
       |-licences 
       |-schema       

Here is the list of the most significant directory names:

• bin contains the commands
• config contains the GHN configuration files
• etc is used to place container and service-specific configurations
• lib contains service & 3rd-party software
• share/gcube_tools contains the gCore build scripts
• share/schema contains service, standard and gCore-specific interfaces

Dealing with Globus

In order to deal with the underlying Globus technology, the following steps are needed:

1. export GLOBUS_LOCATION to the gCore LOCATION
2. export PATH to gCore bin
3. configure ${GLOBUS_LOCATION}/etc/globus_wsrf_core/server-config.wsdd by specifying the hostname as value of the logicalHost parameter

<deployment name="defaultServerConfig" xmlns="http://xml.apache.org/axis/wsdd/" xmlns:java="http://xml.apache.org/axis/wsdd/providers/java" xmlns:wsa="http:/
/schemas.xmlsoap.org/ws/2004/03/addressing" xmlns:wsnt="http://docs.oasis-open.org/wsn/2004/06/wsn-WS-BaseNotification-1.2-draft-01.xsd" xmlns:wsrp="http://d
ocs.oasis-open.org/wsrf/2004/06/wsrf-WS-ResourceProperties-1.2-draft-01.xsd" xmlns:xsd="http://www.w3.org/2001/XMLSchema">

    <globalConfiguration>
        <parameter name="logicalHost" value="localhost"/>
        [...]
    <globalConfiguration>
</deployment>

To test it: start GHN gcore-start-container -nosec (by default on 8080, otherwise start with -p <port>)

GHN Passport

The main configuration file of gCore is GLOBUS_LOCATION/config/GHNConfig.xml:

<?xml version="1.0" encoding="UTF-8"?>
<jndiConfig xmlns="http://wsrf.globus.org/jndi/config">
    <global>

                <environment
                        name="securityenabled"
                        value="true"
                        type="java.lang.Boolean"
                        override="false" />
                <environment
                        name="mode"
                        value="development"
                        type="java.lang.String"
                        override="false" />
                <environment
                        name="rootVO"
                        value="/gcube"
                        type="java.lang.String"
                        override="false" />
                <environment
                        name="defaultVO"
                        value="/gcube/devsec"
                        type="java.lang.String"
                        override="false" />
                 <environment
                        name="infrastructure"
                        value="development"
                        type="java.lang.String"
                        override="false" />
                <environment
                        name="labels"
                        value="GHNLabels.xml"
                        type="java.lang.String"
                        override="false" />
                <environment
                        name="rootGHN"
                        value="true"
                        type="java.lang.Boolean"
                        override="false" />
                <environment
                        name="GHNtype"
                        value="Dynamic"
                        type="java.lang.String"
                        override="false" />
                <environment
                        name="localProxy"
                        value="/home/globus/..."
                        type="java.lang.String"
                        override="false" />
                <environment
                        name="coordinates"
                        value="43.719627,10.421626"
                        type="java.lang.String"
                        override="false" />
                <environment
                        name="country"
                        value="it"
                        type="java.lang.String"
                        override="false" />
                <environment
                        name="location"
                        value="Pisa"
                        type="java.lang.String"
                        override="false" />
                <environment
                        name="updateInterval"
                        value="60"
                        type="java.lang.Long"
                        override="false" />

    </global>
</jndiConfig>

Explanation of each parameter:

• securityenabled ...
• mode (allowed values are development/production)
• defaultVO...
• rootVO...
• infrastructure...
• labels...
• rootGHN...
• GHNtype
• localProxy...
• coordinates...
• country...
• location...
• updateInterval...