Mark Fenbers ha scritto: > I have working PostgreSQL databases on 3 of my ~30 Linux boxes. I want > my software to be able to determine which of my 30 boxes have functional > databases on them. Since Pg is part of the baseline distro, merely > checking for the existence of an executable doesn't solve my problem. > > I tried looping through my list of hosts and running the command: > psql -h $host --list > but this fails on a box with a database with the same error code as on a > box that doesn't have a database, if my PGUSER isn't set and my login ID > is not the username of the database. The PGUSER setting might differ > for each host, so specifying this in the software is not practical. > > Bottom line: What trick can I use to determine whether a box has a > living, breathing Pg database if I don't know the DB owner? > Mark >
Just write a custom client that connects to the given host, on some standard ports. If the connection is accepted, there is a possibility that on the other side there is a PostgreSQL server. To make sure send a StartupMessage http://www.postgresql.org/docs/8.1/static/protocol-message-formats.html You can reuse some code of a library I have written: pglib. http://developer.berlios.de/projects/pglib/ It is released under the MIT license, and it is written in Python and Twisted (a framework for writing asynchronous applications). By the way: pglib aims to be a complete replacement for libpq. Regards Manlio Perillo ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
