维护金字塔项目的定制版本（git分支，代码内变化或其他方法？）

Question

Introduction

I have a simple pyramid project for inventory management, and use git as my VCS. Switching away from git would not be hard, but switching away from pyramid would be. The scope of the project is quite small, meant for use by a single organization, with maybe 5-20 logins max at a time. The project is developed for A.

Problem statement

B also wants an inventory management software, and I wish to re-use what I've already developed for A. There are certain fundamental differences (most importantly, the item models would differ as both A and B are interested in different attributes) as well as view differences (at the very least the logo on the page would differ, and B probably wants different pages based on their usage pattern, much more focused on keeping track of item loans where A is much more focused on ensuring timely delivery of items when purchase orders are sent to external suppliers).

Example of fundamental differences

Both A and B would have models named Item and Group (Child-Parent relationship). However A would keep track of 5 attributes for Item (eg Brand, Part Number, Target Delivery Date, Actual Received Date, Description) while B would keep track of 4 attributes for Item (eg Identification Number, Description, Item type (consumable or re-usable), and Purchase Date).

Alternatives considered

Having multiple branches off a single base (or a single submodule with common code) seems tough to keep synchronized/merged, mostly because I don't seem to have much 'common code' in the sense of fixed directories or files which would not change at all between versions.

Based on this talk - always ship trunk taken from the accepted answer to Workflow for maintaining different versions of a webapp using git? the recommendation is instead to maintain a single branch (trunk/master, obviously feature development is a separate branch) but version in-code with if/else checks on flags. However it seems more suited to multiple versions of the same web-app rather than two (slightly differing) web-apps as in my case.

Which of the above (or other alternatives) would involve the least maintenance burden, assuming both A and B's requirements don't significantly branch away from each other (eg A requests that financial accounting be included, at which point I would actually just fork a separate project)?

Answer 1

I don't know Pyramid, but rather than using a VCS-oriented approach (ie. branches), what you probably want is a modular approach. Something like this:

siteA/
    templates/
    config/
    assets/
    tests/
siteB/
    templates/
    config/
    assets/
    tests/
modules/
    inventory/
    financial/
    image_gallery/

The details of each site are kept separate from each other. They have their own templates, configuration, and assets (images, and whatnot) that describe how they behave and how they look.

Bits of functionality are developed as configurable modules. This is your inventory system, your financial system, an image gallery... whatever.

Then siteA and siteB can individually choose which modules they want to use, configure how they act, and how they look.

The main advantage is that the details of the sites are decoupled from each other, so you can cater to the whims of your individual customers without changing how the other behaves. Someone can work on siteA without worrying about breaking siteB. Common functionality is put into the modules which have a more formal, documented interface.

The main disadvantage is that if A and B have a lot in common it can get redundant. There's various ways to mitigate that: push more common functionality into the modules, create shared templates, symlink to common templates and assets, improve the default configuration of modules, or even branches.