Overwriting Schema Settings in Runtime

Added by Uri Cohen, last edited by Aleia Hutcherson on May 25, 2008  (view change)
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Overview

The built-in schemas configuration covers most of the common scenarios.
It is commonly required to change only a small part of the built-in configuration. Obviously this could be done by creating a new type of schema. However, this could very easily lead to a large number of schemas that could be hard to maintain. To address this requirement, the schemas property values can be overwritten in various ways:

Overwriting Schema Values Through System Properties

Variables are usually provided in the following form:
${variable name} – The value for this variable name can be provided as part of a System property, i.e., -D<variable name>=<value>. For example, if you want to overwrite a property of the root directory of Gigaspaces during runtime without changing any of the configuration files, you can use the following format:

In the schema file:

<some element>..${com.gs.home}...<some element>

In the script that runs, Gigaspaces will set the value for this variable in the following format:

Java ... -Dcom.gs.home=./ ...
The property value must be set before GigaSpaces is launched. In each XML configuration element, there could be only one variable as part of the element value.

Setting Initial List of Variables

The list of variables in the configuration can be relatively long and often requires changes to the command line arguments. To simplify that process, it is possible to load all of the variables required during instantiation of a specific GigaSpaces instance through a configuration property file.
The property file will contain the same properties in the form specified above. In addition, is possible to overwrite certain value through an XPath variable, i.e., without the need to put a specific variable attribute as part of the configuration file.

For example:
The container configuration file includes the following:

<jndi>
<!-- true if enabled, false otherwise -->
<enabled>true</enabled>
<url>localhost:10098</url>
</jndi>

To set the <url> value with the JVM property, modify it as follows:

<url>${com.xx.localhost}</url>

This value is interpreted, when parsed by GigaSpaces, to contain the value of the property com.xx.localhost.
Make sure you start GigaSpaces with the syntax: Dcom.xx.localhost JVM property.
For example: -Dcom.xx.localhost=localhost:10098.

The same result can be achieved without setting this system property, but instead setting the Xpath key in the properties file/object:

com.j_spaces.core.container.directory_services.jndi.url=localhost:10098

SpaceURL new ?properties option

While passing the ?properties=MyProps attribute to the Space URL (it does not have to come together with the ?schema= option), the system will search for the MyProps.properties file under /config/MyProps.properties according to the classpath.
For example, you can put the properties file at: c:\myFolder*\config\myProps.properties*
Now all you need to do is to add it to the classpath, e.g.: -classpath c:\myFolder.
Then, it loads it as a Java Properties object, which is passed to the system.

CLI / API

A Properties object can be created and passed to the CLI (via -properties new option) or any of the SpaceFinder.find() methods. A Properties object also can be passed via the existing JSpaceAttributes object.

Jini ServiceStarter

When the Jini ServiceStarter, JSpaceServiceImpl wrapper is used, you can pass a "properties=" together with the "schema=" attributes via the /config/services/gigaspaces.config file.

The container.xml file (which is created if multiple spaces are loaded in the same container) has a new <properties> tag in case a user wants to specify a properties file with details to overwrite the space <schema> details, e.g :

<?xml version="1.0"?>
<container1>
   <JSpaces>
      <sp1>
         <schema>cache</schema>
         <properties>myOverwrittenProps</properties>
         <load-on-startup>true</load-on-startup>
       </sp1>
       <sp2>
         <schema>persistent</schema>
         <properties>sp2</properties>
         <load-on-startup>true</load-on-startup>
       </sp2>
...

Default gs.properties File Example

When specifying a space URL, you may use the properties file or have as part of the container file the <properties> tag. This should include a properties file location with a list of properties that override the cluster, container, and space default values.

# ==================================================================================
# GigaSpaces configuration overwriting file, used for overwrite
# the space and container schema properties as well as other system properties.
# If client has requested to load a properties file (or passed a Properties java object), 
we attempt to load the properties file
# from <GS dir>/config (if <GS dir> is in the classpath) or from an http url.
# if it is found, we load it to the system, set these attributes to the SpaceURL
# properties data structure.
# Any system property set overwrites any other settings; the Properties file (or user defined
# custom Properties object which might be passed) is then parsed, its properties are injected to the system
# and later used to override the space/container/cluster configurations, as well as other VM system properties.
#
# The following types of properties are supported as part of the properties object/file:
# ======================================================================================
# 1. space/container configuration - the prop key is the XPath of the element as it set in the space/
container schema xml file.
# e.g. For space config: space-config.lrmi-stub-handler.protocol-name=rmi
# e.g. For container config: com.j_spaces.core.container.directory_services.jini_lus.enabled=false
#
# 2. cluster configuration - the prop key is the system property set into the ${elementname} 
in the cluster schema xml file.
# 3. System properties - the key must start with -D, and indicates the system to set that key/value 
as a system property.
# 4. SpaceURL attributes - the key must start with gs.space.url.arg.<atribute name> e.g. 
gs.space.url.arg.
total_members=111
# or gs.space.url.arg_line=schema=persistent&cluster_schema=async_replicated&total_members=
3&id=2&nowritelease=true&fifo=true&create
# - The space url args should be all in lower case.
# - Usage of the ${xxx} setting via a system property is valid in any scenario, but that will be overwritten
if option number 1 is used.
#
#
#
#===================================================
# Space and container XPath PROPERTIES:
#===================================================
## Cluster config related settings:
# To enable the cluster
#space-config.cluster.enabled=true
#The static members cluster xml file needs to be located in <root dir>/config folder, e.g.
#c:/myFloder/config/multi-site and the c:/myFloder needs to be added
#space-config.cluster.config-url=/config/multi-site
#### Examples for other optional cluster config urls:
#space-config.cluster.config-url=/config/gershonsTest-cluster-config.xml/config/gershonsTest-cluster.xml
#space-config.cluster.config-url=D:\\GigaSpacesEAG4.1\\config\\default-cluster.xml
#space-config.cluster.config-url=/config/default
#space-config.cluster.config-url=/config/myAsyncRepl-cluster.xml
# Moving GigaSpaces Log into debug level [5]
#com.j_spaces.kernel.log.cache.detail_level=5
## Types of supported loggers com.j_spaces.kernel.log.FileLogDriver;System.out;
com.j_spaces.kernel.log.Log4jDriver
#com.j_spaces.kernel.log.cache.output.classes=com.j_spaces.kernel.log.FileLogDriver;System.out
#com.j_spaces.kernel.log.enabled=false
# To disable GigaSpaces shutdown hook
#com.j_spaces.core.container.shutdown_hook=false
##### Jini Lookup service container config related:
#com.j_spaces.core.container.directory_services.jini_lus.start-embedded-lus=false
#com.j_spaces.core.container.directory_services.jini_lus.enabled=false
#com.j_spaces.core.container.directory_services.jini_lus.unicast_discovery.enabled=true
#com.j_spaces.core.container.directory_services.jini_lus.unicast_discovery.lus_host=host:port
#to overwrite the space config implicit-indexes just add the line:
#space-config.number-implicit-indexes=-1
#to overwrite the space config lrmi protocol
#space-config.lrmi-stub-handler.protocol-name=rmi
#to overwrite the space config serialization-type just add the line:
#space-config.serialization-type=0
 
 
#===================================================
# SYSTEM PROPERTIES:
#===================================================
# RECOMMENDED: Common RMI related system properties settings
#
#When it is necessary to ensure that DGC clean calls for unreachable remote references
#are delivered in a timely fashion, the value of this property represents the maximum interval
#(in milliseconds) that the Java RMI runtime will allow between garbage collections of the local heap.
#The default value is 60000 milliseconds (60 seconds).
-Dsun.rmi.dgc.client.gcInterval=600000
-Dsun.rmi.dgc.server.gcInterval=600000
#-Djava.rmi.server.RMIClassLoaderSpi=default
#if this value is true, incoming calls and exceptions thrown from incoming calls will be logged to System.err.
#Setting this property to true will greatly assist you in debugging your RMI programs.
#-Djava.rmi.server.logCalls=true
#If this value is true, details of rmid's logging activity are sent to System.err.
#-Dsun.rmi.log.debug=true
#-Dcom.gs.onewaywrite=true
## Common debugging logging options:
# RECOMMENDED: To turn on the Webster HTTP web server logging
#-Dorg.jini.rio.tools.webster.debug=true
# RECOMMENDED: set to true to see the cluster configuration debug output
#-Dcom.gs.clusterXML.debug=true
# RECOMMENDED: To enable client side logging
#-Dcom.gs.client.debug=true
# RECOMMENDED:setting the system property of the jini Java logging file location. Use it to enable 
finest logging trubelshooting.
#-Djava.util.logging.config.file=${com.gs.home}/config/services/gs_jini_logging.properties
#set the cluster member url's prefix
#-Dcom.gs.cluster.url-protocol-prefix=rmi://localhost:10098
#to set the license key
#-Dcom.gs.licensekey=
#-Dcom.gs.home=C:\GigaSpacesCache5.0
 
#===================================================
# Space URL attributes:
#===================================================
#gs.space.url.arg.total_members=10
#gs.space.url.arg.id=2
#gs.space.url.arg.schema=persistent
#gs.space.url.arg.nowritelease=true
#Other optional attributes (add each to the gs.space.url.arg. prefix):
#backup_id, clustergroup, clustername, cluster, cluster_schema, groups, fifo
#updatemode, versioned, uselocalcache, timeout, securitymanager, nocache, create, destroy
# Example how to set a list of Space URL attributes:
#gs.space.url.arg_line=schema=persistent&id=2&total_members=10&Create

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