To be able to install the plugin to Taverna, Taverna needs to be able to find the artifacts required. This is possible using Maven repositories. A maven repository is simply a http based file server such as Apache. If you with to be able to share your plugins with other Taverna users you will need to set up this server so it is publicly accessible on the Internet.

Full details of how you deploy your artifact can be found by reading the Maven documentation, but here is a brief summary of deploying via ftp, the most likely scenario.

First you will need to define within the pom.xml for your plugin project the location the artifact is going to be deployed to.

<project>

...

  <distributionManagement>
    <repository>
      <id>my-ftp-repository</id>
      <name>My Ftp Repository</name>
      <url>ftp://webserver/var/www/html/maven/repository/</url>
    </repository>
  </distributionManagement>

...

  <build>
    <extensions>
      <extension>
        <groupId>org.apache.maven.wagon</groupId>
        <artifactId>wagon-ftp</artifactId>
        <version>1.0-alpha-6</version>
      </extension>
    </extensions>
  </build>

...

</project>

where webserver is the name of the server you are deploying to, and /var/www/html/ is the Apache server document root. /maven/repository/ is a sensible place to put your repository on you server, but you can of course choose your own. The declaration of wagon-ftp is also required for Maven to be able to find the extension to support ftp.

Since Maven will need to know the user name and password for the transfer, and you obviously don't want to declare these within your project file, these are defined within your Maven settings.xml as follows:

<settings>

...

  <servers>
    <server>
      <id>my-ftp-repository</id>
      <username>user</username>
      <password>pass</password>
    </server>
  </servers>

...

</settings>

The settings.xml file can be found within $HOME/.m2/settings.xml when using Linux or the Mac, or "Documents and Settings\<user>\.m2\settings.xml" when using Windows.

Maven also supports deployment using ssh.

Once this has been set up then the plugin is deployed using the maven command 'mvn deploy'.

If your plugin has additional dependencies that are not available through the myGrid or Maven Central repositories, you will need to publish those within your repository also. You can do this by using the mvn deploy:deploy-file command to deploy individual jar files. If you find the artifact is available in another repository your can use that but will need to include that repository in the list of repositories when describing your plugin in the next section.

Once the artifact is deployed, it is necessary to describe the plugin before it can be installed into Taverna. This comprises of two simple xml files. The first file provides details about your plugin and contains the following content, using the myGrid Feta plugin as an example:

<plugin>

  <name>Feta</name>
  <description>Service discovery</description>
  <identifier>uk.org.mygrid.taverna.plugins.feta</identifier>
  <version>1.1.1</version>
  <provider>mygrid.org.uk</provider>

  <repositories>
    <repository>http://www.mygrid.org.uk/maven/repository/</repository>
  </repositories>

  <profile>
    <artifact groupId="uk.org.mygrid.feta" artifactId="feta-client" version="1.1.1"/>
  </profile>

  <taverna>
    <version>1.5.1</version>
  </taverna>

</plugin>

Although many are self explanatory, here is a description of all the elements:

This information is stored in an xml file named of your chosing, though a name that reflects the plugin and version is clearly advisable.

The next xml file is a list of the plugins avaliable at your site, and has to be named pluginlist.xml. This contains a simple list of the files just produced, which can either be declared as relative or absolute locations. E.g.

<plugins>
  <plugin>feta-plugin-1.1.1.xml</plugin>
  <plugin>http://www.somefaroffplace.org/another-plugin.xml</plugin>
</plugins>

The final step in publishing your plugin is to place these files on a http server where they can be accessed from Taverna, once again somewhere publically accessible if you wish to share your plugin with Taverna users. The http server that hosts your repository, but within a seperate directory not within the repository, would be a natural location.

Now all thats required is to install your plugin into Taverna. This is done through the Plugin Manager -> Find Plugins -> Add Plugin Site.

The URL should point to the root directory that the pluginlist.xml was published, not directly to the pluginlist.xml file itself. If all has gone well, once adding this your plugin should appear in the list of available plugins for installation.

However, what is probably more interesting here is what happens once the plugin site has been defined and the plugin installed.

When the site is added an entry is added to a pluginsites.xml file in $taverna.home/plugins/ which is created if it didn't already exist. This file looks like:

<pluginSites>
  <pluginSite>
    <name>My Plugin Site</name>
    <url>http://mypluginserver.org/plugins/</url>
  </pluginSite>
</pluginSites>

Once the plugin itself is actually installed, it is added to a file plugins.xml in the same location. Taverna inserts the information from the plugins xml definintion into this file. So for using our Feta example this would look like

<plugins>

...

  <plugin>
    <name>Feta</name>
    <description>Service discovery</description>
    <identifier>uk.org.mygrid.taverna.plugins.feta</identifier>
    <version>1.1.1</version>
    <provider>mygrid.org.uk</provider>
    <enabled>true</enabled>

    <repositories>
      <repository>http://www.mygrid.org.uk/maven/repository/</repository>
    </repositories>

    <profile>
      <artifact groupId="uk.org.mygrid.feta" artifactId="feta-client" version="1.1.1" />
    </profile>

    <taverna>
      <version>1.5.1</version>
    </taverna>

</plugin>

...

</plugins>