What are all the means of application configuration?

princepawn has asked for the wisdom of the Perl Monks concerning the following question:

Since there have been very few New Nodes today, I thought I would give everyone something to -- on. Heheh.

Most of you are familiar with Andy Wardley's App::Config module. If not, let me explain. This module reads a series of key = value pairs from a text file, with the ability to store these key/value pairs in appropriate keyed hashes. E.g.,

[db]
username = Python
password = sucks

[backup]
machine   = guido
frequency = 4 hours

[logging]
file      = /var/log/applog
level     = 2
[download]

This would create a nested hash, with backup, logging and db as first-level keys, accessible from your program as:

$app->{logging}->{file}
[download]

Or, you can make use of easy nested navigation (a functionality oft-reapeated in other modules --- (Data::DRef, Boulder, cpan:Template) and separate the elements of the path with dots.

Anyway, what I am realizing is that there is a least one other way of initializing an application, and that is via its command-line arguments (Getopt::Long, Getopt:Std, Getopt::Mixed).

So I began to wonder, how many ways can (and should) a Perl application allow itself to be configured? Let's not forget we could also have per-user configuration which portends the use of databases keyed on username (like the Almighty Technological Innovation of One-click Ordering at Amazon.com --- lol).

So give your input. -- to your heart's content. Share your experience. Do something exciting on this Monday morning we all wanted to be over 6 hours ago.

Over and out, the Monk You Love to Hate princepawn. heheh

Comment on What are all the means of application configuration? Select or Download Code

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RE: What are all the means of application configuration? by Zarathustra (Beadle) on Oct 03, 2000 at 00:20 UTC
Lets not forget about XML. XML::Simple makes for an excellent app config also. `app.rc: <app> <db> <username>Python</username> <password>sucks</password> </db> <backup> <machine>guido</machine> <frequency>4 hours</frequency> </backup> <logging> <file>/var/log/applog</file> <level>2</level> </logging> </app>` [download] Derives the same access: `$app->{'db'}->{'username'}` [download] As well as all the good stuff that comes with xml, such as for checking the "config" file ( actually just another xml doc ), for well-formedness and validity. Also, XML will provide ties for easy config-file update and modification via the application itself, should you choose to use something like XML::Writer. A fun and nice way of getting fancy for say, a web editable/creatable configuration file.	[reply] [d/l] [select]
Re: What are all the means of application configuration? by wardk (Deacon) on Oct 02, 2000 at 21:58 UTC
Not a real "exciting" answer but since it is monday, and yes it should have ended a good six hours ago, I'll bite :-) On a recent project, I used the following: Determine environment - determine hostname (dev/prod) and directory structure (on dev box, we have dev/test) Application settings - stored in RDBMS User settings (for theming, etc) - Cookies 5 hours, 58 minutes to go...	[reply]
Configuration can occur via Environmental Variables by princepawn (Parson) on Oct 02, 2000 at 22:02 UTC
I noticed something in wardk's post and it triggered an association. You can use environmental variables to configure an application also!!!!! Mind-bending. At least we on the east coast only have 2 hours and 30 minutes to go. HAHAHAHAHAHA!!!	[reply]
Re: What are all the means of application configuration? by ncw (Friar) on Oct 02, 2000 at 22:47 UTC
Some modules (like CPAN) store their config in a specialised Module (like CPAN::Config). This is a technique I've used too!	[reply]


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