An Improved Approach to Generating Configuration Files from a Database Jon Finke Rensselaer Polytechnic Institute

Conclusions Cuts development time –Standard development environment –Host interface written once –Code sharing with web routines –All work done centrally –PL/SQL well integrated to Database Platform independence

The Old Way Custom program for each file type. –Common file system –Small number of platforms –Standard development environment –Lots of cut and paste C coding –Direct access to tables and views

Old Model Relational Database SQL*NET File Format Logic Version Control SQL*NET File Format Logic Version Control

The Problems Loss of common file system –Harder to distribute custom programs Multiple development environments Program logic unavailable to web applications. Minor file format changes require too much work.

New Model SQL*NET Version Control SQL*NET Version ControlFile Format Logic Relational Database Switcher File Format Logic

New Way File format logic stored in DB –Changes made centrally Generic file extraction program –No changes after installation –Platform independence Code sharing with web applications PL/SQL programs are shorter –Faster to write

Stored Procedures and Packages PL/SQL –Procedural extension to SQL Simple Procedure or Function Package –Set of procedures and functions –maintains state Stored and executed by database server

PL/SQL Variables and Constants SQL built in functions –String, Numeric, Date Conditionals Looping Constructs Exception Handling Records

Generic Program Get Filename Null? Done Start Open File Get Line Null? Write Line Version?

“Switcher” functions Standard API for generic program Provides access control Provide filename for simple cases –Also direction, and other attributes Grouping of multiple simple files Environment info for specific file generator routines.

Switcher Get_Filename Record? Return Null Access OK? Return Error Get Next Target Rec Simple? Open? Open Target Rec Files>0? Return Rec.GetFname() Return Rec.Filename

Target Record Target Name, Sequence Number Access List Get Data Routine Name Get FileName Routine Name (C) FileName (S) Direction, DBMS_OUT Flag (S) Version Info (S)

Get_Data (1) Cursor Get_Records is Select Username, Uid Gid, Gecos, Shell, Path from Logins;... Procedure Get_Data(Result out varchar2) is RGet_Records%RowType begin if not Get_Records%IsOpen then Open Get_Records; end if;

Get_Data (2) Fetch Get_Records into R; if Get_Records%NotFound then Close Get_Records; Result := Null; else Result := R.Username || ‘:*:’ || R.Uid || ‘:’ || R.Gid || ‘:’ || R.Gecos || ‘:’ || R.Path || ‘:’ || R.shell; end if; return;

Complex Targets Get_FileName –Like Get_Data –Stashes context info for Get_Data –Provides version info (optionally) Keep calling until no more files. For each file, call Get_Data until no more data.

More Conclusions Replacing existing custom programs Loading data as well as extraction Handler for back end processing –File “STDOUT” Wish I had done this long ago

Package Design Relational Database Tables WP Table Routines WP Web WP File Web ServerFile Gen

Files Currently Generated White Pages –LaTeX, HTML, LDIF, ph, CSV Hostmaster –Resource Record (bind) –Hostfile –DHCP Config TSM Billing –Error Reports

Files Currently Loaded TSM (Backup/archive) –Accounting Records White Pages –CSV staff list (remote campus) Terminal Server –Accounting logs lpd (printing) –Accounting logs

Futures GET from program PUT to program Boilerplate management Call file generation from Web –Faster development for web pages –Alternate Boilerplate testing More platforms

An Improved Approach to Generating Configuration Files from a Database Jon Finke Rensselaer Polytechnic Institute