Andrew Hicox > Config-Framework-2.5 > Config::Framework

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NAME ^

Config::Framework - handy one-stop shopping for (most) of your configuration file needs.

SYNOPSIS ^

#create a new object, load two configuration files and decrypt the passwords. my $Object = new Config::Framework( Files => ['ApplicationCfg.xml','UserCfg.xml'], GetSecure => 1 ) || die $Config::Framework::errstr;

#change some data in one of the loaded configs $Object->{'UserCfg'}->{'backgroundColor'} = '#00CCFF';

#write that change back to the file you loaded it from $Object->WriteConfig(configNamespace => "UserCfg") || die $Object->{'errstr'};

#Define a new configuration namespace %{ $Object->{'newConfig'} } = ( 'configNamespace' => "newConfig", 'protectNamespace' => 1, 'Version' => 1, #arbitrary data keys follow 'backgroundColor' => '#006699', 'getRecords' => 10, 'followLinks' => 1, 'someThing' => "in a bag" );

#Write your new configuration data out to an encrypted file #under the application's ApplicationFramework directory $Object->WriteConfig( configNamespace => "newConfig", Encrypt => 1, Crypt => "Rijndael", Key => "l33tp4sw3rd" File => "$Object->{'FrameworkDir'}/newConfig.xml" ) || die $Object->{'errstr'};

OVERVIEW ^

At long last I have decided to re-write the documentation for Config::Framework, in a manner which should be comprehensible by people other than myself. I would like to offer my sincerest appologies to anyone who tried to comprehend the sprawling stream-of-consiousness rant that was the previous 'documentation'. I'm sorry, I wasn't trying to make you insane. Now on with the show.

Ok so what is Config::Framework? It's a handy module for dealing with situations where you need your program to be able to load external data from a file that controls how your program operates. I'm talking about configuration files here. So what do you do in a situation like that? Well you figure out a format to store your configuration parameters in, then write routines to read that format and put it some sort of meaningful data structure, and to write data from the data structure back out to the file.

Wouldn't it be nice if someone defined a standard config file format so that you wouldn't need to write your own parser? Well in the end, all a config file really is, is an arbitrary data structure expressed in in ascii. A standard way of serializing data structures in ascii you say? That sounds a bit like XML! Well the Data::DumpXML module will serialize perl data structures into XML and restore them for you, and you could certainly dump that to a file easily enough.

Ok getting to the point. The main thing that Config::Framework does for you is to define a standard data structure (or at least some standard guidelines for your data structure) and then front-ends Data::DumpXML so that you can arbitrarily dump and restore these data structures to files.

While we're at it, Config::Framework aspires to be your 'one-stop-shop' for config-type-stuff, by helping you stay organized in the way you handle external configuration data.

Directories ^

When it comes to your program needing to load external files, things can quickly get messy. Config::Framework helps you stay organized with this by defining a directory structure that you can use for all of your programs.

The Virtual Root

Config::Framework defines something called the 'virtual root'. This is a master directory underneath which all of your programs, and all of the things that they might need to load or operate correctly would live.

When you first build the Config::Framework module, the Makefile.PL will prompt you to enter a directory to use for your Virtual Root. This will be the default Virtual Root for all objects that you create. That is whenever you create a new Config::Framework object, unless you specify a different Virtual Root (via the 'v_root' option) the directory you entered when you were building the module will be your Virtual Root.

Let me give you a quick example of why this is important. I had a rather large group of perl programs, some of which I had written, others which i had inherited from others. All of them lived beneath a certain directory structure which was allocated for my department by the unix help-desk. Almost all of these programs had one file or annother which they would need to load to run, all of the paths were hard-coded. One day help-desk decided to change our directory. Mass confusion, and one REALLY LONG night of me picking through all of the programs trying to change hard-coded file paths ensued. Had I been using Config::Framework, all I would have needed to do was rebuild the module with a new virtual root. Well that's the story of why I started development on this module. Aaaah yes, those were good times ...

The Config Location

Under the Virtual Root, Config::Framework defines a subdirectory, beneath which it is presumed you will be keeping all of your configuration files. This is referred to as the "Config Location" or $object->{'config_loc'}. As with the Virtual Root, you will be prompted for a default config location when you build the module. You can override the default config location by specifying the 'config_loc' option at instantiation. When you load a configuration file, Config::Framework will look for it here first (unless otherwise specified). Generally speaking, you should put "Global" configuration data here, that is, configuration data that all programs might use.

The Framework Directory

Beneath the Config Location, Config::Framework expects to see a subdirectory named "ApplicationFrameworks". Beneath that should be subdirectories for various programs. For instance, if I had a program called "Skeletor" and it needed a configuration file called "Skeletors_Config.xml", a gif called "trogdor.gif", and a berkley DB file called Skel.db, I would create a directory under the Virtual Root in the Config Location under the ApplicationFrameworks directory called Skeletor, and I'd put Skeletors_Config.xml, trogdor.gif, and Skel.db in there. Sounds confusing. It isn't here's annother go at that:

Virtual Root = /prod Config Location = config

cd /prod/config/ApplicationFrameworks/Skeletor; ls; Skeletors_Config.xml trogdor.gif Skel.db

Got it? Ok so every program that needs to load specific external files should have a directory beneath the ApplicationFrameworks directory that corresponds to it's program name. In that directory is where you should put everything that the program might need to load. Things that multiple programs might need to load should be put at the root level of the config location.

When you load a config file with Config::Framework, the second place it looks (after the config location) is the subdirectory of ApplicationFrameworks that corresponds to the program's name.

Access to your data! ^

Ok so that pretty much lays out how things are kept organized in the filesystem. How about organizing access to all these gobbs of data? I'm glad you asked, 'cause I was gonna tell you anyhow. You might recall that I mentioned earlier that the heart of Config::Framework was a standard data structure for your configuration data which is serialized and stored in a file, and then miraculously restored to perl data-structure-hood via the Data::DumpXML facility. Before I lay out exatly what that standard data structure is (well actually it's pretty much just some guidelines), let me tell you about a really cool name I came up with: "configNamespace". This really cool, complicated sounding thing is a word I came up with to describe the concept of having more than one set of configuration data resident in the Config::Framework object at one time. For instance, I may have a global configuration file that holds some general purpose data like the hostname of my oracle server and the port that my SSL server listens on. Stuff that lots of programs might want to know. In annother config file, I might have some application specific data like the maximum number of multiple process for this program I want to have running at once, and a regular expression matching record numbers for a certain database. I would want to have them both loaded with my Config::Framework object at the same time, so I needed to come up with a way that I could differentiate between the two sets of config data. So what I did was to make each config file define a 'configNamespace' under which it resides in the Config::Framework object. That's a fancy ways of saying it's a string that happens to be a hash key in the object. This is a key concept for using Config::Framework. For instance, back in my example, I could make the global config file define the configNamespace 'global', and the application specific file define the configNamespace 'myApp'. So to access the global data I would look under $object->{'global'} and for the app specific data I would look under $object->{'myApp'}.

The Data Structure ^

Well like I said this is more of a guideline than it is a standard. Only the mandatory parts are, well mandatory. The rest is just a suggestion. For instance, you don't need to include information about the autors or module dependancies, However, if you WANTED to include that information, this is how I suggest that you do it. Ok, strap on your perl hats, here we go:

The data structure is basically a giant hash:

%DATA = (

        ## Mandatory Information ########################

        #the configNamspace to load this data under in the Config::Framework object
        'configNamespace'       => $configNamespace,
        
        #throw an error if this configNamespace is attempted to be overwritten (by loading
        #annother config with the same configNamespace) if set to non-zero value.
        'protectNamespace'      => 1 | 0,
        
        #revision of this configuration
        'Version'                       => $version_number,
        
        
        ## Optional Config Meta Data ####################
        
        #date corresponding to the last revision of this configuration
        'Date'                          => $date_in_epoch_format,
        
        #automatically load these files and nest their configNamespaces underneath this one.
        'children'                      => [$file_name, $file_name, ... ]
        
        
        ## Author Data ##################################
        
        #name of the lead developer for this project
        'Lead Developer'                => $lead_developer_name,
        
        #lead developer's email address
        'Lead Developer Email'  => $lead_developer_email,
        
        #the others in the development team
        'Developers'                    => [ 'array','of','other','developers' ],
        
        
        ## Program Specific Keys ########################
        
        #would go here. Any goofy thing you want.

);

And that's pretty much it.

Passwords ^

Passwords are one special kind of config data that programs frequently need to load. For instance, do you have a program that needs to talk to a database? How about one which needs to talk to an SSL Website? Well then it probably needs to have a username and password. It's kind of bad form to have passwords and usernames hard-coded into programs. Especially if you have lots of programs, then you have both the nightmare of updating all of the hard-coded passwords in each program when the password gets changed, as well as the security risk of having a password in perhaps tens or hundreds of individual files. One option is to stick those usernames and passwords in a configuration file or course, so that many programs can access the same file. However, you've still got your passwords hanging out 'in the nude' in a file somewhere waiting to be discovered. Config::Framework provides some built-in options to help you, if not eliminate, to at least to mitigate that risk.

Config::Framework knows how to decrypt a file encrypted with any of the Crypt::* modules which is Crypt::CBC compliant. When you specify the 'GetSecure' option at object instantiation, Config::Framework knows to look for a file called 'passwds.xml' located at the root level of the config directory.

When you build Config::Framework, the Makefile.PL will ask you for a Crypt::* module to use to and a passphrase to use to decrypt and encrypt this file. Sure, the passphrase is still 'in the nude' somewhere buried in your perl distributions lib/ directory, and theoretically, someone could go digging through that directyory, and find the passphrase, then use it to get all of the passwords in your passwds.txt. However, it's better than nothing. Like I said this mitigates the risk a bit, it dosen't eliminate it. At the moment there really aren't any good systems available to perl to handle passwords securely. At least this way, you have your password access abstracted a bit, so when something like that comes along, we can add support to Config::Framework.

Logging / Alerts ^

Ok something that's not config file related, but is none-the-less important, and so is therefore included in the one-stop-shop that is Config::Framework is the ability to keep log files, and to let someone know when something bad has happened with your program.

When you build Config::Framework, you are prompted to enter the email address of someone who should be notified when a program using Config::Framework dies unexpectedly. This is a bit misleading. An alert will not be sent to this address automatically, you must catch your own exceptions and call the AlertAdmin function with your alert message.

As with all of the other default parameters gathered durring the build process, this address can be overridden at object instantiation. To override the admin address send a new email address on the 'admin' object at instatiation.

Config::Framework also provides support for appending messages to alert files via the 'Log' method.

Alrighty Then Ok so that's pretty much what Config::Framework does. How about the specifics? Read on courageous programmer! ^

new (constructor) ^

This creates a new Config::Framework

my $object = new Config::Framework( [options] ) || die $Config::Framework::errstr

options

program

This is the 'name' of the program. This defailts to the name of the executable file if you don't specify it explicitly.

v_root

This is the 'Virtual Root': the directory under which all of the external things your program will need to live happily reside. (See above section: 'Virtual Root'). If not specified explicitly, this value defaults to the virtual root specified when the module wad built.

config_loc

This is the directory beneath 'v_root' which contains all Config::Framework loadable config files as well as the ApplicationFramework directories (see above section 'The Config Location'). If not specified explicitly, this value defaults to the 'config_loc' specified when the module was built.

sendmail

This is the path to the sendmail executable, which we pipe directly to when sending alerts via the AlertAdmin method. If not explicitly defined, this value defaults to the path to sendmail given when the module was built.

admin

This is the email address of the person whom we should send email alerts to by deefault when the AlertAdmin method is called. If not explicitly defined, this value defaults to the admin address given when the module was built.

Crypt

This is the Crypt::* module to use when encrypting or decrypting encrypted configuration files, such as the infamous passwds.txt. (See the 'Passwords' section above). Keep in mind that whatever Crypt::* module you specify must be Crypt::CBC compliant, and of course, you must have it installed already! If not explicitly defined, this value defaults to the Crypt::* module specified when the module was built.

Key

This would be the passphrase to use when encrtpying or decrpting encrypted configuration files, again, such as that infamous passwds.txt (see 'Passwords' section above). If not explicitly defined, this value defaults to the passphrase given when the module was built.

EnvExportList

This is a sticky-wicket, thrown in for backward compatibility. This is an array conaining a list of strings which are data keys which you would like to have exported to the shell environment. There are 5 default members of this list: 'SYBASE', 'ORACLE_HOME', 'ORACLE_SID', 'ARTCPPORT', 'LD_LIBRARY_PATH' This means that if you happen to have defined any of these options, either explicity at instantiation, or through the build process as a default option, the values associated with these options will be exported to your sheel environment. Mucking with this is hardly ever worthwhile, if you're looking for a quick and easy way to export stuff to the shell environment, check out the 'Export' option.

Export

This is a hash refrence of variable names and values that you would like to have exported to the processes shell environment. For example to set the 'BLAH' variable to "ain't it grand?", you could do this:

$object = new Config::Framework( Export => { 'BLAH' => "ain't it grand?" } );

SYBASE

if you have a sybase client libraries installed, and you would like to set the environment variable SYBASE to this value, you can specify it here and it will be exported. (it's part of the default 'EnvExportLIst'). If you don't explicity define this, and you did define it duirring the build process, it will be exported to your shell environment by default. This is meant to be the path to the Sybase client library distribution.

ORACLE_HOME

the path to the oracle client librarry distribution. Like SYBASE, this is in the default EnvExportList, so if you define it, expect for it to be exported to the processes shell environment

ORACLE_SID

the SID of an oracle database you would like to connect to. A default member of EnvExportList (see above).

ARTCPPORT

the port that you would like to talk to a Remedy ARS server on. A default member of EnvExportList (see above).

LD_LIBRARY_PATH

linker library path. believe it or not, you need to have this defined for a whole lot of things to run correctly under *nix. So if you defined a library location under v_root when you were building the module, this will be exported to the processes shell environment. You can also, obviously specify it explicitly here.

GetSecure

If set to a non-zero value, this will cause Config::Framework to automatically load and decrypt the encrypted config file 'passwds.txt' under v_root/config_loc.

File

This is a list of config files to load before returning the object. Well this can either be a string containing one file name, or an array reference contaiing multiple file names. Keep in mind that each file must define it's own unique configNamespace for this to work correctly.

LoadChildren

if set to a non-zero value will automatically load all child configs specified in any config that is loaded into the object. The default value for this object is 1. To override this behaviour, just set the option to 0.

LoadConfig ^

This loads a configuration file into the object under the configNamespace specified in the file. If there is already data loaded under this configNamespace in the object, and the protectNamespace option is set in the existing config data, an error will be thrown.

$object->LoadConfig(File => $file_name) || die $object->{'errstr'};

options

File

this should be a string containing the filename of the file containing configuration data that you would like to load. The file is looked for in the following locations: IF the file exists as you have specified it (that is if you specified the full path to some file, and it exists there) then the file will be loaded. Otherwise, if it exists in the root level of v_root/config_loc (the location for global configuration files) it will be loded from there. Else if it exists in v_root/config_loc/ApplicationFrameworks/$object->{'program'} (where $object->{'program'} is the name of the program (see 'new (constructor)' above), then it loaded from that directory. Lastly, if the file is not found in any of those locations, we look in the home directorry of the user executing the process (this is determined via $ENV{'HOME'}). Using this precendenc allowes a great deal of flexibility ... just remember to keep tour config file names unique! ;-)

configNamespace

IF the file you are loading DOES NOT specify it's own configNamespace, you can specify one explicity in the function call using this parameter. This should be a string you would like to use for the configNamespace-less file you are loading.

Parent

you may specify a parent namespace under which to nest the configNamespace of the file you are loading. For instance. If I have an application called 'Daleks' which has a config file with a configNamespace of 'Dalek' and a user preferences file which specifies the configNamespace 'usersDalekConfig', then I might do something like:

$object->LoadCondfig( File => "usersDalekConfig.xml", Parent => "Dalek" );

this would load the user-specific config file UNDER the 'Dalek' configNamespace, so that I could access the user-specific data thusly

$object->{'Dalek'}->{'usersDalekConfig'}->{'someKey'};

Crypt

LoadConfig has the capability to decrypt and load config files encrypted via one of the CBC compliant Crypt::* modules. This option specifies the Crypt::* subclass that you would like to use to decrypt the specified config file (presuming it is encrypted). For instance, if you wanted to load the file "mySecretConfig.xml" which was encrypted using the Crypt::Rijndael module you would do something like:

$object->LoadConfig( File => "mySecretConfig.xml", Crypt => "Rijndael", Key => $mySecretKey ) || die $object->{'errstr'};

NOTE: this option defaults to the Crypt::* subclass specified when the module was built, if not explicitly defined either at this function call or at object instantiation.

Key

(see Crypt option above). This is the passphrase to be used to decrypt the configuration file using the Crypt::* subclass specified on the 'Crypt' option.

NOTE: this option defaults to the passphrase specified when the module was built, if not explicitly defined either at this function call or at object instantiation.

WriteConfig ^

This will write the data under some configNamespace in the object to the file it was loaded out of, or alternately to a different specified file. Encrypted data is handled transparently.

$object->WriteConfig(configNamespace => "usersDalekConfig.xml") || die $object->{'errstr'};

options

configNamespace (required)

This should be a string indicating the configNamespace that you want to dump back into the spcified file. Obviously, the configNamespace that you specify must already exist in the current object.

File

This is the file that you want to write the data contained in the specified 'configNamespace' back out to. If this option is not specified explicitly, then the file from which the specified configNamespace was loaded is used. The same file location precidence that is used in LoadConfig is maintained here. That if the file as specified is not writeable, then we look first under v_root/config_loc, then v_root/config_loc/ApplicationFrameworks/$object->{'program'} and lastly in the user's home directory.

Encrypt

if set to a non-zero value, this will cause the file which is being written out to be encrypted with either the specified Key and Crypt or the default options given when the module was built. NOTE: setting this option is not necessary if you are writing data back to a file which was encrypted when you originally loaded it, this option is only necesary if you are encrypting a file which was not previously encrypted, or if you are creating a new encrypted file.

Crypt

This should be the CBC compliant Crypt::* subclass that you would like to use encrypt the data. If not specified, this option defaults to the value givne when the module was built. For more information, see ReadConfig.

Key

This should be a string contining the passphrase you want to use to encrypt the data with the specified CBC compliant Crypt::* subclass. For more information, see ReadConfig.

LoadXMLConfig ^

This function will load any specified file in the Data::DumpXML DTD. If a binary file is specified it is presumed to be encrypted. Encrypted files are decrypted using either a specified Crypt::* module and passphrase, or the default options specified when the module was built. Data is returned via a hash reference, and is NOT loaded directly into the object.

$data = $object->LoadXMLConfig(File => "path/to/some/file.xml") || die $object->{'errstr'};

This is the backend to LoadConfig which handles inserting config data into the object under the correct configNamespace, and also handles child configs and nested namespaces. If you just want to get some raw data out of a file in the Data::DumpXML dtd, which might possibly be encrypted using a Crypt::* module which is CBC compliant, then this is the method you're looking for.

options

File

again, this is a string containing the complete path to and name of the file you would like to load. No location precidence mathing occurs here, you must specify the entire path and file you want to load.

Crypt

This would be the CBC compliant Crypt::* subclass that you would like to use to decrypt the given file, presuming it is, in fact, encrypted. (See LoadConfig method)

Key

This would be the passphrase you'd like to use to decrypt the (presumably encrypted) config data using the CBC compliant Crypt::* sublcass you specified above. (see LoadConfig method)

AlertAdmin ^

This will email an alert to the address specified by either the 'To' option, or the default address specified when the object was built. Additionally, the method can optionally copy the message to a group of addresses, log the message to a file, or call the die() routine. This is accomplished via a piped shell process which calls the sendmail binary. If we are unable to open a pipe to the sendmail process, as a last resort we will attempt to append the specified message to a logfile located at v_root/var/log/last_resort.log.

$object->AlertAdmin( Message => "I can't log in to the database, bailing out!", Log => "copy/this/message/to/my/log/file.txt", Die => 1 ) || die $object->{'errstr'};

options

To (optional)

a string containing the address to send the 'Message' to, or alternately, a reference to an array containing a list of multiple addresses to use. If not explicitly specified, this option defaults to the admin address given when the module was built.

Message (required)

a string (possibly a very long one) which contains the data you would like to send.

Log

if specified, this will cause the method to attempt to append the 'Message' to the specified log file, tagged with the current date and time.

Die

if set to a non-zero value, this will cause the program to terminate itself after sending the 'Message'

ENV

if set to a non-zero value, this will cause the method to append the entire contents of the global %ENV hash to the end of the 'Message'

Log ^

This will append the given 'Message' to the specified 'Log' file. The log file is presumed to live beneath v_root somewhere. If you want to use system-wide loging locations, you might want to use sym-links to accomplish that.

TO DO: add syslog support via Net::Syslog or Sys::Syslog so that messages can be logged to a remote syslog server or put in the machine's local syslog. That's far less ghetto than appending messages via the open >> method.

$object->Log( Message => "hey, I wasn't able open that file, moving on to the next one!", Log => "path/under/v_root/to/my/log/file.txt" ) || die $object->{'errstr'};

options

Log

this should be the complete path to (starting under v_root) and name of the file you want to put log messages in.

Echo

if set to a non-zero value, this will cause the 'Message' to be warn'd to the console in addition to being appended to the file. (good for debug modes).

Message

this is the message you would like to have placed in the log file. The message will be prepended with the date and time in epoch format, enclosed in brackets. For instance the call above would result in something like this appearining in the file "path/under/v_root/to/my/log/file.txt":

[1064852564]: hey, I wasn't able open that file, moving on to the next one!

Die

if set to a non-zero value, this will cause the process to terminate after writing the message to the specified log file.

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