Introduction
To publish a data collection using an Astrogrid Datacenter Server, carry out the following steps:
- Install the system pre-requisites
- Download the appropriate PAL Webapp
- Deploy PAL to the servlet container
- Configure the dataset and PAL
- Create a description of the data collection
- Restart the servlet container
- Test the installation
- Register the data collection with the Virtual Observatory
Pre-requisites
This page describes the software components that must be installed and configured before installing the Datacenter Server. The Datacenter Server relies upon the following software components, which must be installed and configured before installing the Datacenter Server.
Download PAL
The publishers astrogrid library is distributed as a J2EE Web Application (.war) file.
The latest snapshot of PAL can be downloaded directly from
here. You can find
other versions, jar files, etc for the AstroGrid project here
Deploy PAL
You can use the Tomcat manager to install PAL (see the Tomcat manager instructions) or you can do it by hand - Copy pal.war to the webapps directory of your tomcat installation and restart your server:Once tomcat has been restarted, the pal web application will be unpackaged into the directory webapps/pal-SNAPSHOT. If installed on your machine in the default location, the web application root will be http://localhost:8080/pal-SNAPSHOT.
Configure PAL
This page describes in detail how to configure your datacenter. However once PAL has been installed, it should be possible to run the installation tests and some cone queries on it, as it contains a simple SQL database by default. Note that some of the self tests will fail until you have completed the setup process. The errors they report should give you some indication of anything you have missed. Read the configuration page before going on, as you will need to make a new configuration file to connect to your data.
Describe your data
For your data to be published to the VO, it must be capable of presenting an XML document that describes that data. This allows the VO's automatic tools to analyse what is available.
The config pages describe how to make these. Once this is done and you are happy with the results shown on the metadata pages, click on the 'Register' link in the admin pages
Verify the installation
Pal comes packaged with a series of self-test scripts. To run these, visit the web application root, and navigate to the self-test page. Inspect the result from each script - no errors should appear on the output.
Logging
The datacenter uses 'commons-logging' to log messages; on a Tomcat server this is routed to the server's Log4J logger. A default log4j properties file is included in the distribution, and can be found at /WEB-INF/classes/log4j.properties in the web application.
By default, the properties file causes INFO and higher messages to go to std.out (these can be found in the catalina.out file when using Tomcat), INFO and higher messages are stored in pal.log, and DEBUG and higher messages are stored in a rolling file (it is size limited) called pal-debug.log. These latter two are found in ${CATALINA_HOME}/logs/ when running under Tomcat.Running test queries
The datacenter web application contains simple web forms (see the navigation links on the main index page) to submit queries to the datacenter service.
In addition, the client delegate jar contains simple command-line tool that will fire a adql query at the server and display the VOTABLE response. You need to write an adql query that conforms to the adql schema (downloadable from the web application) and save it to a file.
