Many of our projects are ‘greenfield’ and we have the opportunity to do things the way we like. By working on new projects every few months, as opposed to one project over the course of years, we have lots of opportunity to easily tweak and tune the way we do things. Not all of our projects are from scratch though (see Alon’s post about Rewrite or Rescue), so we sometimes end up dealing with years worth of history and crufty code. It’s safe to say that each time we roll onto one of these projects, there’s going to be some level of bewilderment regarding what developers deal with on a daily basis.
Maybe it’s because we have a special opportunity to optimize the hell out of our development process, or the fact that we’re all productivity junkies; regardless of the reason, we religiously embrace the tenant “Make the things you do often fast and easy”. It’s almost embarrassing to suggest that others don’t also subscribe to this simple notion, but — brace yourself — many do not. On a project that has history, not everyone has been there for every decision. In fact, many developers are at least relatively new and it’s somewhat customary to have a “it must be this way for a reason” attitude. After all, who would deliberately make something cumbersome without good reason?
When we start working on one of these projects, we dedicate time to do some serious spring cleaning and tackle the things that will cost us the most in terms of pain and productivity. The whole development team gets psyched about where we end up as it’s a significant improvement. Projects with a history usually have a fair bit of low-hanging fruit. Let’s discuss some of the things we see regularly.
Apparently few people like working on build scripts and when they do they have a habit of lowering their standards for quality of work. That’s obviously not literally true, but sometimes it seems that way. We’ve seen a number of beastly build systems that are slow because they’re doing things that aren’t necessary (extraneous jaring, copying, code generating, etc), they’re brittle and expensive to maintain, and full of dead code and duplicate target definitions… and they’re run many times every single work day. It’s true that most developers may be compiling code from their IDE and thus bypassing the command-line build, but it’s still run on the build server, by ops folks, and even by developers when they’re debugging why something works from the IDE but busts on the build server.
Guidelines for simplifying the build
- Distill the build process down to the fastest, simplest steps that are necessary.
- Eliminate duplicate and no-longer used dependencies; these files are being copied around and bundled for no reason (I’ve seen over 15 megs of unnecessary dependencies before).
- When a project is split into multiple modules (and it should if it’s more than a few thousand lines), modules should be built in a consistent fashion using targets that are shared across modules.
- Look for exceptions. When you see something special happening for a particular file type, file name, or modules, ask yourself why. Ask again. Strive to eliminate these special cases when possible, even if they seem trivial.
- Build a single deployable (or deployables) for all environments by eliminating environment-specific build code and externalizing application configuration. (Use Spring? Check out this post on externalizing configuration with Spring.)
- Look for unnecessary code generation steps; if generated code changes once a year then check it in and make regenerating a manual step.
- If you generate code coverage data, make sure that it’s only created when it’s needed (e.g. a nightly build on the build server), not on every build.
So, we use Maven 2 for all of our Java projects. For sure, it has its share of rough edges (most of which are being fixed at a reasonable rate). But it recommends some very sound conventions and doesn’t provide any scripting functionality, so it’s harder to hack it to do anything too unorthodox (please don’t use the antrun plugin unless as an incremental step when moving from Ant to Maven). When you play ball by the Maven rules you’ll find your build much simpler and easier to maintain. It’s likely you’ll notice other emergent benefits to boot. For example, once you migrate to Maven you eliminate duplicate build configuration (both your command line build tool and IDE know how to compile your app — remember the DRY principle). IDEA, Eclipse (via m2eclipse), and NetBeans all support importing from and synchronize with Maven.
Some people use Buildr or Ant + Ivy, but either they don’t have the breadth of use (Buildr) or are more susceptible to writing nasty, unmaintainable build code (Ant). That’s why we use Maven.
Compile > Deploy > Make Changes > Deploy Development Cycle
Possibly more important than a simple and easy build, developers must be able to go through the compile, deploy, make changes, deploy cycle FAST (note that the compile, run tests, make changes, run tests cycle is also very important).
I remember working on an embedded system in 1998: a complex radio communications routing application written in C++ and deployed to custom hardware running the real-time operating system PSOS. The build and deploy cycle took about 30 minutes and there were only 10 hardware instances for 60 engineers; you had to sign up for time slot on real hardware. It was the epitome of unproductive as far as development environments go (and don’t even ask about debugging!). You’d think such things were completely in the past (luckily they mostly are), but they’re not completely. In the last 2 years I’ve seen applications that take 15 minutes to deploy.
It’s a drag when developers have to wait for these things to happen and it can totally destroy one’s rhythm, keeping developers from getting into the zone. What’s worse, it’s completely unnecessary with modern tools.
- Don’t drop down to the command-line; compile and deploy from your IDE (the IDE is your friend – master it).
- Minimize steps for deploying changes to a running app:
- Your IDE may support building on frame deactivation (IDEA does); check it out.
- Look into the maven-jetty-plugin if you use Maven.
- Run in debug mode so that code can be hot-swapped or invest in JavaRebel, which allows all sorts of code changes to take place without redeploying your application.
- Deploy your application in exploded form; bundling a war or ear incurs unnecessary IO overhead.
- Host your database either locally on your workstation or on a beefy database server on the same LAN. Remote databases are generally many times slower due to latency, even over fast connections.
- Use JBoss? Consider migrating to Jetty or Tomcat. If that’s impossible, use the most stripped down profile (minimal, default, or all) that has what you need, or better yet, create a custom one which includes only what you need.
- Minimize the amount of data needed in the database to run the application. The same goes for running tests: do whatever it takes to run your tests against an empty (or very close to) schema. Check out the Carbon Five DB Migration Project.
- Don’t skimp on developer hardware. Buying the very fastest CPU isn’t going to be worth it, so aim for one or two models down from the fastest. Buy the fastest hard disk you can since development is generally IO bound (WD Raptor and the new VelociRaptor are awesome, consider SSDs if your coffers run deep). Avoid older CPU architectures (Pentium D), even when the clock speed (GHz) is faster. Lastly, don’t be shy with memory; 4GB isn’t too much for a developer machine.
In addition to these general recommendations, each individual application will have its own specific sources of inefficiency. Many real world applications depend on services provided by application servers and/or a commercial products: message queues (JMS, ActiveMQ, etc), distributed caches (memcached, coherence, etc), enterprise service buses, job schedulers, work flow engines, etc. It’s important that these services don’t get in the way of developing fast. Some of them can be run in a light-weight development mode. If you need to use one of these potentially heavyweight solutions, invest the time to minimize or eliminate any adverse effects to the development cycle.
Some of the best improvements have nothing to do with the technical side of software development. Take a step back and look at what else is happening (or not happening) each day. There may be meetings which can be time boxed, consolidated, or eliminated all together. Take a look at collaboration between engineers, product managers, testers, support and operations. How long are developers waiting to have requirements-clarifying questions answered? Ask your whole team where they think things can be improved. Ask for feedback on a regular basis and allow it to help drive these improvements.
Survey of other activities that should be fast and easy
- Running the automated test suite – < 10 minutes
- Getting build results from continuous integration server – < 10 minutes
- Pushing a build to staging/acceptance server – One click build and deploy
- Create a new instance of a minimal database instance – Carbon Five DB Migration Project
- Recreate production state in development for debugging
- Story approval/acceptance – Continuous acceptance
- Meetings – Timebox, Consolidate, Eliminate
- Configure a new developer machine – Strive for zero configuration
Any intelligent fool can make things bigger, more complex and more violent. It takes a touch of genius and a lot of courage to move in the opposite direction. -Albert Einstein
There’s a theme underlying most of the solutions to these problems: simplicity. Complex systems don’t become complex and crufty overnight, they get that way one small step at a time. With each change to a system it’s important to recognize that the change will either add complexity or remove it. Complexity has a cost and it’s not to be taken lightly; make sure the benefit to each of the decisions that add complexity is worth that cost.
Making the things that people do often fast and easy can pay off geometrically as all developers benefit and regain a little more of their day (and sanity). In the end, it’s not just about shaving off seconds or minutes, though that’s a huge part of it; it’s about creating a development environment that lets the team do what’s really important: write awesome code to solve real problems. When the team dynamics, technical environment, and process are tuned just right, the overall benefit is greater than the sum of its parts.
Where have you seen changes in infrastructure, software, or process that’s resulted in a significant productivity bump?