Sometimes it’s easier to create a good Continuous Integration system from scratch than it is to improve a system which has been all bent out of shape to support bad practices or legacy issues. But if you’re going to take a wrecking ball to your CI system and start again, exactly how do you actually start? Well, in my experience, the best implementation I’ve worked on has been when the customer’s requirements were clearly understood first.
Start at the Beginning
Rather than go ahead and start by choosing your favorite CI tools and defining a standard system, start by picking up a pen and paper and go and speak with as many people involved in project delivery as you possibly can. This should include BAs, Project Managers, Testers, Developers and Systems Architects. Ask them what inputs and outputs they would expect to see and receive from the build and deploy system. Ask them what manual steps they do – you never know, your CI system might be able to help automate some of their work, even for the BAs. Quite often, Project Managers want to see quality metrics from their projects, and to get these they often rely on a manual process, perhaps expecting QA to produce bug statistics or asking a developer to produce some build reports. It seems that quite often, people are unaware of exactly what a CI system can really do for them.
Using the feedback from these sources, start to define a system on paper and continue to get feedback on your design. This needn’t be a long task, but it will help to stop you from going down the wrong path early on. Concentrate on simplicity and consistency. An over elaborate system will be hard for people to understand and then support, and ultimately that can be damaging. Don’t have several systems all doing the same thing, just have the one, reduce wasteful repetition. Don’t have 2 different types of build server in use unless you have to. Don’t support 2 types of static analysis tool that effectively measure the same thing, instead, settle on one.
In your design, be sure to include:
- A Source Control system
- A build tool or tools
- Unit test framework(s)
- A static analysis system
- A reporting mechanism (possibly a dashboard)
- Integration and Acceptance testing
- A deployment mechanism
Design your system with the aim of making it work seamlessly, all the constituent parts should ultimately work together in an automated flow. You will find, as the system gets used, that there are likely to be several manual inputs into your system which it may be possible to automate further. For instance, I have seen an automated Hudson/Bamboo plan creation system using selenium, where users have only to input a fraction of the number of details than they would otherwise need to!
Target bottlenecks. Invest a proportionate amount of time addressing the high priority, high value parts of the system. Work out where the bottlenecks were in the old system (or the manual system you are hoping to replace) and invest the right amount of time working on those areas. There’s no point producing a system that can reliably deploy software to any OS when you only need to support one, especially if your build process is shaky and could do with more attention!
Choose your Tools Carefully
When deciding what tools to use for your system, there are a number of things to consider. The obvious ones are cost, suitability for purpose, performance and scalability. But consider other factors as well, such as how readily available the support for your tools is, check out the user communities presence and their support coverage. Also consider personal preference! If a whole team really want to use a particular tool for some reason, perhaps they’ve been excited about it for some time, then at least consider using it, you know it will get that team’s support!
Before you start the hard (but fun) work of implementing your system, be sure you get the buy-in you need from the management. I’m not just talking about getting approval, I literally mean buy-in. Management should feel invested in this system. Sell the system to them by highlighting the existing issues that it is going to help solve. The more the management teams buy into Continuous Integration, the more support it will get, the more it will be used, and the better we become at making software. If we fail to get management buy-in, we can easily be left with a system that is all too easily overlooked and ignored, and we can end up with a Continuous Integration System, but not actually practicing Continuous Integration.