An Alternate Data Distribution Client

update_mirror.py is a simple client for the IPP distribution system. It requires only Python 2.6 to run; the IPP software need not be installed. The script understands the IPP distribution system communication protocol and is intended to be run from cron to implement daily updates of a mirror site.

The advantages of the script are simplicity, brevity, ease of installation and ease of operation. Potential disadvantages are:

• The script does not maintain a local MySQL copy of the distribution source database. This can be imported directly, however, and the corresponding information is available in the .mdc files of the distribution.
• The script is not intended to serve as a distribution server in its own right, so it cannot form part of a distribution chain using the IPP distribution mechanism. The mirrored files can be redistributed using rsync, however.
• The distribution protocol is pretty stable, but it may change at some future time. That change will break the script until a corresponding update can be made.

Installation Instructions

1. Create an empty directory on the filesystem where you want to mirror the data distribution. On Odyssey the corresponding directory is /n/panstarrs/data/MIRROR .
2. Copy update_mirror.py and parse_config.py into that directory.
3. Customize update_mirror.py for your site, by editing it and making the following changes:

1. set mirrorRootDir to the root directory of your mirror, presumably the directory created in step (1) above.
2. set desiredProductList to contain a list of the data products you want to mirror.
3. Possibly update topURI, if the distribution server at IfA has changed from its current host.
4. Possibly modify hiddenProductList to include the names of new data products not visible from the top distribution layer. This bit is a little cryptic- the original spec for the distribution mechanism said that the data products would be visible from the top level directory of the distribution server, but this has been changed for security reasons. New products are now announced on the IPP mailing lists and must be edited into hiddenProductList manually.