It’s very common to have a code check-out step be part of an integration build. Far better it is to not check out code before a build. What? How is that possible?

Let me explain, Fred. The simple approach most of us take (and have to take when getting things started) has developers commit, commit, commit, and when it is time to deploy, check out the code, do a build, and then deploy the application. There is room here for both problems and optimizations. Doing a full check out of the code tree is more costly in terms of time than checking out only what has changed. Updating the code tree with a single commit is less costly than updating with a large number of commits.

You may be limited by the technology in-hand and how much you’ve invested in learning the technology and possibly customizing it. For example, if your file control tool can only do a full check out of a source tree, or that’s the only command you had time to implement in order to meet the deadline, or you don’t trust your tool to do incremental updates, then you are basically running the longest builds possible.

On the other hand, if you could update the code tree every time a developer does a commit with only the changed files, then you are ready to execute a build at any moment. This requires some deft manipulation of your file control tool, and that’s why you don’t see it more often.

You might think “continuous integration” will take care of this. Developer commits, update checked out, build is run. However, you may end up with a build, test execution and deployment that takes longer than the typical time between developer commits. You still have to do incremental updates and it only solves the problem in cases with very low developer activity.

I’d like to point out one tool that does an excellent job of post-commit code checkout, CA Software Change Manager for Distributed. CA SCM (for short) is the tool, formerly known as Harvest, from the company formerly known as Computer Associates. CA SCM is a highly scalable (1000’s of developers) file control tool with a great lifecycle process model. We at OpenMake Software still have our very first customer still using OpenMake/Meister with CA Harvest/SCM after 11 years. While we have a reseller arrangement with CA, our partnership with CA in services has extended to 14 years.

About 10 years ago, OpenMake Software developed an integration with the then, Platinum Technologies’ Harvest product, modeled after the now dead Computer Associates product, Endevor Workstation, that had an excellent post-action code tree update. (Endevor for z/OS, a.k.a CA SCM for Z/OS is still very popular and has a similar functionality called ‘output libraries’ - following all this?) Our integration had the horrific name, ‘Har-refresh’.

As product partners, we finally transitioned Har-refresh from an external add-on to CA who have turned it into a core functionality of the product, called Hrefresh (a better name.) Rather than simply a post-commit check out, HRefresh updates the code tree after any action that updates a dynamic code view. This includes, renames, deletions, commits and code promotions and demotions. We like this because CA SCM does all the work and we cherry-pick sets of up-to-date code trees to build up an application source code stack for a build. We align Meister dependency directories with HRefresh-managed file system directories for a tight SCM (software configuration management) build.

This mechanism distributes the resource load for checking out code to times when builds are not required. It’s true that often times people want to build as soon as their code is checked in (or promoted), but on average it is a very big net win reducing build times.

This is just an example of the type of sophistication that is out there to prevent pre-build code check outs and save time on your builds.