Overview

A far file is a versioned package containing java archives (jar/zip files), native code dynamic libraries (dll/so files) and other support files that can be shared between several fabric applications. This package is deployed to a running fabric. In addition, libraries listed in the far XML file will be visible to any fabric application that references that far file in its fabric application definition XML. Java jars listed in the java-libs element will be seen by the fabric application's Java class loader. Native dynamic libraries listed in the libs element will be loadable by the fabric application.

All files included by the far must be in the same directory or a subdirectory as the far XML, and the pathname must be a relative path.

Far XML sample

<?xml version="1.0"?>
<far name="deployable_misc_stuff" verison="1.2.3">
    <java-libs>
        <file name="somejar.jar"/>
        <file name="some_subdir/someOtherJar.jar"/>
    </java-libs>
    <libs>
        <file name="some_dependency.dll"/>
        <file name="subdir/some_other_dependency.dll"/>
    </libs>
    <support-files>
        <file name="something.txt"/>
        <file name="subdir/something_else.txt"/>
    </support-files>
</far>

Tag descriptions

<libs>
    <file name="some_dependency.dll"/>
    <file name="subdir/some_other_dependency.dll"/>
</libs>

<java-libs>
    <file name="some_dependency.jar"/>
    <file name="subdir/some_other_dependency.jar"/>
</java-libs>

<support-files>
    <file name="data_file.txt"/>
    <file name="subdir/other_data_file.dat"/>
</support-files>

Far file creation

The far is packaged with fabric_pkg. After the far xml file has been created and the files moved into the appropriate directory hierarchy, the deployable far file can be created with fabric_pkg create. Once created, the .far file can be deployed to the fabric using the fabric_ctl command, in the same manner as deploying a .fabric file.

App packaging with far dependency

When packaging an application with a reference to a far, one should take care to provide the location of the .far to fabric_pkg. By default, fabric_pkg will look in $FABRIC_HOME/fars for any far files it needs for packaging; the far lookup directory can be changed by using the -fars-dir option in fabric_pkg. If, for some reason, a far file listed in App XML is not present, fabric_pkg will print a warning message, but will continue to try packaging the application. In the case that the CLASSPATH or LD_LIBRARY_PATH/PATH are already set properly on the user's development environment, the application should package. Otherwise, errors will occur later in the packaging process due to unsatisfied dependencies. Once the application is deployed, however, the application will refuse to start unless its far dependencies are met and the correct fars are deployed.

Far XML Schema

<?xml version='1.0' encoding='utf-8'?>
<xs:schema id='FabricArchive' targetNamespace='http://www.appistry.com/far'
	elementFormDefault='qualified' xmlns='http://www.appistry.com/far'
	xmlns:mstns='http://www.appistry.com/far'
	xmlns:xs='http://www.w3.org/2001/XMLSchema'>
  <xs:element name='far'>
    <xs:complexType>
      <xs:all>
        <xs:element ref='java-libs' minOccurs='0' maxOccurs='1' />
        <xs:element ref='libs' minOccurs='0' maxOccurs='1' />
        <xs:element ref='support-files' minOccurs='0' maxOccurs='1' />
      </xs:all>
      <xs:attribute name='name' type='xs:string' use='required'/>
	  <xs:attribute name='version' type='xs:string' use='required'/>
    </xs:complexType>
  </xs:element>
  <xs:element name='java-libs'>
    <xs:complexType>
      <xs:sequence>
        <xs:element ref='file' minOccurs='1' maxOccurs='unbounded' />
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name='libs'>
    <xs:complexType>
      <xs:sequence>
        <xs:element ref='file' minOccurs='1' maxOccurs='unbounded' />
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name='support-files'>
    <xs:complexType>
      <xs:sequence>
        <xs:element ref='file' minOccurs='1' maxOccurs='unbounded' />
      </xs:sequence>
    </xs:complexType>
  </xs:element>
  <xs:element name='file'>
    <xs:complexType>
      <xs:attribute name='name' type='xs:string' use='required'/>
    </xs:complexType>
  </xs:element>
</xs:schema>