Difference between revisions of "Software Development (WG1) Version Control (T3)"

Revision as of 21:55, 16 November 2005

Setting up a VistA Development Environment

Overview

This is a description of how VistA development environments should be configured.

Bold text designates program names, directory names, command line parameters, etc., that are intended to be typed in at a Linux shell or a GT.M prompt, e.g. /bin/bash. Italic text is a descriptor of something whose actual value must be determined when the command is typed, e.g., gtmver.

Theory

A release is a collection of routines and global variables. The canonical packaging of a release, which is suitable for importation into any standard M distribution, is a collection of M source code routines and a database extract in ZWRite format. When installed on a system, to run with an M implementation, a release may have pre-compiled object files, database files, shell scripts, global directories, etc.

Below is a diagram of the “roll-up” by which a VistA release (“Release A”) gets converted into another VistA release (“Release B”) by a development team. A and B could be from different families, e.g., Release A could be a FOIA release and Release B could be a Leonardo da VistA release.

Once Release A is installed, it remains frozen and unchanged except for any essential patches that may become available independent of the development process for creating Release B and without which the release lacks some required functionality.

At any given time, there can be multiple development projects underway based on Release A. In other words, there may well be a Release C that is also based on Release A, but which has its own integration and development areas.

To start the development process, an integration directory is created and initialized with a copy of the global variables from Release A, as well as shell scripts, global directories, etc. The integration directory may well have a different name from Release A and Release B. For example, Release A may be FOIAVistA_20051021, Release B may become LeonardoDaVistA_0.4 (at the time that the integration area is created, the name and version of Release B may not be decided yet), and the integration and development areas may be named Greenbelt_200510. There is no need to copy routines, since the GT.M search path will be set up to look for routines in the integration area before looking in Release A; hence only routines that are different between Release A and the new release need to be duplicated.

Practice