Last thing I was working on before Christmas was adding searching into CLUMP. CLUMP’s search function uses LUMP’s FindSuid API to find a list of Module structural units which contain the search term in the selected data element (at the minute the data elements supported are Module Title, Module Code and Academic’s name).
There are two reasons that CLUMP searches for Modules rather than reading lists. The main reason being, if a module has multiple reading lists it is better to take the user to the module to see all the related reading lists.
The second reason is that all the current data elements that can be searched are related to the module structural units and not the reading list structural units, and it would be a bit convoluted to get a list module structural units and then look up the reading lists for each one.
With the snow and ice still covering jolly old Loughborough our thoughts naturally turn to Christmas, or more specifically Christmas presents. Will we get that present we really want or will it be socks yet again! So as you don’t end up with just a pair of socks we thought we’d put a little extra in your stocking: the alpha release of LORLS 6.
Please feel free to download and install this first release of LORLS 6 and let us know what you think of it. However it does come with the following health warning: “This is an alpha release – it’s absolutely NOT recommended for production usage.”
We’re getting to the point at Loughborough where we’re considering “going live” early next year with LUMP, replacing the existing LORLSv5 install that we have as our current production reading list system. As such, we’ve just spun up a new virtual server today, to do a test LUMP install on it. This machine has a fresh CentOS installation on it, so needs all the Perl modules loaded. As we use Net::Z3950::ZOOM now, this was one of the modules installed (along with a current YAZ tool chain).
Once we’d got the basic LUMP/CLUMP code base installed on the machine I grabbed the existing LORLS database from the machine it resides on, plus the /usr/local/ReadingLists directory from the LORLSv5 install on there, in order to run the create_structures LUMP importer script. Which then barfed, complaining that “Net::Z3950::RecordSyntax::USMARC” was a bareword that couldn’t be used with strict subs (LUMP, and LORLS before it, makes use of Perl’s “use strict” feature to sanity check code).
Hmm… odd – this problem hadn’t arisen before, and indeed the error appeared to be in the old LORLSv5 ReadingListsItem.pm module, not any of the LUMP code. A bit of delving into the modules eventually turned up the solution: the new Net::Z3950::ZOOM doesn’t do backward compatibility too well. There was a load of code in /usr/lib64/perl5/site_perl/5.8.8/x86_64-linux-thread-multi/Net/Z3950.pm that appeared to implement the old pre-ZOOM Net::Z3950 subroutines, but it was all commented out. I realised that we’d not had this issue before because I’d run the importer on machines that already had LORLSv5 with an older copy of Net::Z3950 on them.
The “solution” was simply to uncomment all the sub routines under the Net::Z3950::RecordSyntax package. The create_structures script doesn’t actually use any of the LORLSv5 Z3950 stuff anyway, so its not an issue – we just need the old LORLSv5 modules to install so that we can use them to access material in the old database. I guess this goes to show the problems you can accrue when you reuse a namespace for a non-backwardly compatible API.
Jason and I have been batting code back and forth for the last couple of weeks to provide an API and CLUMP interface to adding and removing people from usergroups. We’ve gone through several iterations of designs and implementations and now have something that seems to be working OK on our development installation – hopefully soon to appear on the demo sandbox (unless Gary decides that he wants it to work in a different way! 😉 ).
With that more or less done, and some POD documentation tweaks (‘cos I’d been doing a bit too much cutting and pasting between scripts!), I can now go back to dealing with some of the backend management scripts. The first two of these will be a simple link checker and a cron-able script to (re-)populate the “held by library” information. Gary has a couple more reports that Library staff have asked for, but they might just require a couple of APIs to be produced to allow existing reporting systems to work (they weren’t part of the distributed LORLS code base – just local Loughborough reports).
Gary has presented the new system to several groups recently with mostly positive feedback. We’ve just installed a link to this blog (and thus the demo sandbox system) into the live LORLS installation’s managelist script at Loughborough so that more academics will get a heads-up that something new is around the corner.
Since we released the LUMP sandbox on to an unsuspecting and innocent world a week or two ago, we’ve noticed that quite a few people have been playing with it. Which is great – its just what we hoped folk would do. Have a footle, take it for a spin round the block, kick the tyres, etc, etc.
However there’s been a resounding silence in the feedback front. Either this means that:
- folk are so awestruck by its ground breaking novelty that they don’t know what to say,
- or it just works so nobody has any bug reports or enhancement suggestions,
- or is so shoddy nobody thinks its worth bothering with,
- or we released it at a really stoopid time when most University support stafff are (like us) preparing for the onslaught of the hoards.
If anyone who has played with the sandbox does have any feedback we’d love to hear it… even if its just ‘meh’…
I’ve been doing a bit of backend infrastructure creation on LUMP today – a set of seven CGI scripts to help with managing usergroup memberships. These are:
- Usergroups4SU – provide a list of usergroups that are involved in ACLs for a given structural unit.
- Members4Usergroup – provide a list of users that a members of a given usergroup.
- UserGroupMembership – provide a list of usergroups that a user is a member of.
- Editing/AddUser2Usergroup – add a user to a given usergroup.
- Editing/RemoveUserFromUsergroup – remove a user from a given usergroup.
- Editing/AddUsergroup – create a new usergroup.
- Editing/RemoveUsergroup – remove an empty usergroup (ie one with no members).
Jason is going to take these in the next week and see if they are sufficient to allow CLUMP to provide a nice graphical interface for staff, librarians and administrators to add and remove users from user groups. We’ve already got the Editing/EditACLs API CGI script though, so Jason can already tinker with the ability of usergroups to view and/or edit structural units. We might find that we need some other API calls for admin usage, but this little lots should give us quite a bit of functionality.
We now have a demonstration version of our new reading list system available for everyone to play with. The last couple of weeks we have been making lots of little tweaks to the system to get it to the stage we felt comfortable with letting others play with it.
The link to our demonstration site is https://sandbox.lboro.ac.uk/CLUMP/
You know I loved CPAN until I started writing the LUMP installer but now I’m not so keen!
It looks like our cunning plan of allowing people to install the required modules to run LUMP from CPAN using point-n-dribble web front end might have come unstuck for a couple of reasons. The major one is having Perl modules that use XS to rely on C code/libraries/etc that might not actually be installed on the target machine. For example we need to use the ZOOM Perl module for Z39.50 access. This in turn makes use of the Yaz toolkit, which you either need to build from source or get an RPM for… and there aren’t any RPMs in the standard CentOS repos (you can pull CentOS RPMs from Index Data’s web site but not get them via yum). Similar requirements for Expat, although at least that has yum’ed packages in CentOS. I not noticed either of these because on my Debian Lenny based workstation there were already handy packages in place and the Perl modules that I’d been “needing” were pure Perl. I only stumbled across the issue when Jason created a “sandbox” virtual machine running CentOS and I tried to run the installer on there. Even if I could guess the package manager on use on the machine (yum, apt, etc) I’d need to ask the Admin for the system root password and then have to deal with the out of repo code such as Yaz. At this point the law of diminishing returns kicked in and we decided we’d wasted enough time trying to make a user friendly installer and it wasn’t going to be easy to get round these problems.
Still, all is not lost: at least the installer code can spot which modules are missing so that you can install them by hand. In fact I’ve left the code into install private CPAN modules – we might as well do as much as possible for the prospective Admin even if we do then need to tell them to break out the C compiler and build some support software. And of course the installer can still do everything else once the required Perl modules are in place – create the DB, import test data, and retrieve and configure the various scripts required.
I also accidentally stumbled across another problem today: DBD::MySQL doesn’t allow column filters in the column_info() DBI method. I was using that to check if the LUMP database schema on the target machine, if present, was out of date compared to the schema embedded in the installer. This is a bit of a pain but relatively simple to code round. The DBI manual page implies that if a DBD module can’t do filtering you might have to handle it yourself: DBD::MySQL just barfs with an error message so I’ve had to embed the call in eval() checks just to be on the safe side.
I’ve also just noticed that I’ve hard coded the Kerberos TGT realm! Oops – we’ll need to change that, especially as we’re just moving ActiveDirectory trees here at Loughborough anyway! We’ll probably also need to add in an override ability for folk with no AD or other Kerberized authentication infrastructure – that shouldn’t take too much work as its just a little tweak inside the LUMP.pm password validation method. Hopefully in a week or so we’ll have little demo system on our sandbox VM that we can then let people play with – a bit like the demo system that we already run for LORLS v5 (our “groundhog day” install, that gets blown away every morning in the wee hours and replaced with a fresh copy… in fact I used the LORLSv5 to LUMP importer to convert that database into our new format for this new sandbox machine as another useful test).
Writing a web driven installer for LUMP in Perl is proving to be, er, “interesting”. Today has seen some useful progress and its probably worth noting some of the tricks used (mostly because they’re rather esoteric and bug hunting might be fun in a few years time when I’ve forgotten why I did what I did!).
The first thing I had to get going was bootstrapping the the required CPAN modules as documented in my previous post. This is now working OK. A few gotchas to note:
- When you fork off a child process from a CGI script that you want to be “long lived” (ie outlive the parent process that has returned some HTML to the user), you need to close down STDOUT, STDIN and STDERR, otherwise Apache hangs around waiting for the child to finish. This can actually be handy, as you can then reopen file handles with those names pointing elsewhere (such as to a session file) and record the output of other tools that the child calls upon (such as the very chatty CPAN::Shell).
- CPAN::Shell doesn’t appear to return a useful error status, so programmatically you can’t tell if your module install worked or not (the verbose output is designed to tell a human). To find out if a module is installed, you have to try to “use” that module again – once installed the use statement should work.
- Talking of use statements its worth noting that these are best done inside eval()’s, as that allows you to capture errors (as in the case of a module that has failed to install). You have to be careful whether you have compile or run time binding though, especially if you’re eval()ing stuff with variables in that you’re planning on instantiating during the run. Perl -cw is your friend as usual by warning you about dodgy compile time issues.
Once I could successfully install CPAN modules in to a private LUMP modules directory, the next thing to consider was the database. The installer CGI script asked the user for the database name, database account and database password to use and then checks to see if it can gain access. For most noobs this won’t work as they won’t have a database/account/password, so the CGI script traps that error and asks if they’d like it to create the database for them. This requires them supplying the database root password and then (assuming its right) creates the database and grants SELECT/INSERT rights to the named user identified by the given password.
The CGI script then checks that this user can connect to the database – if they can’t then something has gone wrong with the basic creation and we have to tell them to fiddle by hand. Assuming that is OK, it then changes back to the database root user to do the schema creation (as the user only has SELECT/INSERT privs). This however called for another hack: we’ve kept the database schema and index definitions in SQL text files. During development we’ve just source’d these in with the mysql command line client – but this won’t work from Perl’s DBI interface and I don’t want to rely on finding the mysql command line client and system()’ing out to it.
So my next trick was another Perl script: the installer_maker. This is a simple filter script that reads a “template” installer script in and writes out a proper installer with a couple of lines in the template replaced by some Perl array structures – one for the table schema and one for the indexes. These arrays simply contain one SQL statement in each element that the installer_maker has ripped out of the LUMP schema and indexes SQL text files. Bingo! We can now carry on tweaking the schema/indexes in the files we’re used to in development, whilst not having to remember to do lots of code twiddling to keep the installer in sync – we just need to run installer_maker before making a distribution. Hopefully that should result in less chance of our dev schemas getting out of step with released production schemas and the bugs that could result from that.
So its looking promising now, and from a user perspective is probably far friendly than the command line Perl installer from LORLS. The next thing to write is a routine in the installer that can check the schema and indexes in a live database against the schema/indexes we have now got embedded in the installer. If they differ in some way we need to tell the admin running the installer and let them decide whether to ignore the difference (bad idea probably), tweak it by hand or (preferably) let the installer tweak their schema/indexes. Hopefully in the long term this will be a useful place to hang LUMP schema/index upgrades on – folk could use the installer not only to load new versions of the Perl code but also update their database structure. That’ll need some serious testing though…