Developing iPhone applications with teams

In my last post, I identified a number of areas that make developing iPhone applications with teams problematic and sometimes difficult. In this post, I'm going to present some of my ideas on how to make it easier.

• Use source control. While this may seem obvious to most developers, there are certain aspects of development that people aren't putting under source control. This includes, mobile provisioning files, certificates, and private keys. I'll expand on these items later.
• Give all developers the team agent credentials. Teams should designate one member to deal with provisioning (add devices and generate mobile provisioning files), but there may be a time when another developer needs to do it (someone is sick or has gone home for the day). This can be a security risk, but until Apple allows admin users in the provisioning portal to do everything that an admin user can do, this is absolutely necessary.
• Each developer should create a separate developer certificate. While the developers should have team agent credentials, each developer should have his/her own account associated with the team. This will allow the developer to create a certificate and install the development builds on a device. I wrote about the process of generating multiple certificates with one private key which is important for developers working on multiple projects.
• Check the distribution private key and certificate into source control. One of the steps in distributing an application either via AdHoc or AppStore is to create a certificate signing request for the company, upload it to the provisioning portal and then generate a certificate. After this has been done, the certificate and private key (exported as a .p12 file) should be checked into source control so that all developers can install the key and potentially generate AdHoc or AppStore builds.
• Create a build script. Use bash or another shell to create a script that checks out the source code and builds the app. For extra credit, have the build script generate a .ipa file to easily distribute the app and then zip it up along with the mobile provisioning file. In addition, I have my scripts zip up the app and the dSYM file and place it in the source tree (I only checkin the AppStore builds as we generally have a lot of AdHoc releases). This allows any developer to analyze the dSYM file in case of a crash. My scripts name the output files using the svn revision and a timestamp to keep things straight. Lately I've modified my scripts to allow a developer to specify the trunk, a specific revision, or a specific tag. In theory, anyone can generate a build with no special knowledge.
• Be careful with source control. This isn't specific to iPhone development and applies equally as well for other types of development. When I start work each day or after a break in the day, I try to remember to update my source code. In addition, I always make sure I checkin my code at the end of the day. In addition, I check in groups of files at a time and avoid doing huge checkins as the more files I touch, the more chance of having a conflict with another developer's changes. I use Versions for a visual Subversion tool. This makes it easy to see what files I've changed and then before I check in my changes, I diff the files to see everything that I'm checking in. I have Versions setup to use Changes to make it easier to compare the files. It does take more time to checkin my changes, but this gives me an additional opportunity to review my changes. If I try to submit and there is a conflict, I carefully review the conflicts.
• Use instant messaging. I've been working from home for 11 years now, so I've been remote on just about every project I've done. I use instant messaging with other developers, our QA, and my project manager. While sometimes it is easier to call, a quick instant message is very valuable in collabarating. It allows be to bounce ideas off other developers and get more information on bugs from QA.

These are just some of my ideas; I'm sure I'll have more and I'm sure not everyone will agree with them. My hope is that these ideas will help me work better on teams.

Feel free to comment and leave your own ideas for team development.

iPhone Development and teams

Since I've been self employed again, I've been working on 3 iPhone development projects. On 2 of the projects, I'm the lone developer (at the moment), with a QA resource and a project manager. On the 3rd project, at its peak, we had 5 developers, 7 or 8 QA folks, and a project manager. This last project has made it painfully obvious to me (more so than the other 2), that Apple has designed iPhone development around the loan developer that has no formal QA.

Why do I say this? Well, for a number of reasons. First off, the whole provisioning thing is quite problematic for a team. The concept that only the team agent can do AdHoc and AppStore provisioning is not realistic. The Team Agent has typically been someone that is the CTO of a company or someone else that is not involved in the project on a day to day basis. We have to pass around the agent credentials in order to do provisioning (admin privileges are not enough).

Second, Xcode's Build and Archive is not maintainable for a team. If one person does the build, another person on the team may have to examine the crash logs and therefore need the dSYM file in the archive that is built. The archive needs to be checked into source control, but Xcode hides it somewhere else.

Third, with Build and Archive in preparation for deploying as either AdHoc or AppStore, the developer is building the app from his local source tree. Almost all projects that I work on are built using a build script so that the builds are done from source control in order to have a reproducible build. Building an app from the local source tree is quite dangerous as a developer may have forgotten to check in a file and then the next person comes along may not be able to build the app.

Fourth, Xcode's managed provisioning isn't all that helpful. It generates a completely wildcard provisioning file which I'm not really sure how it affects different apps when there are different app IDs. In addition, most of the devices that are provisioned aren't on developer machines, but are QA devices and other devices.

Fifth, the 100 device limit for AdHoc provisioning may sound like a lot, but if you have a team with 5 developers, each with 3 or 4 devices (iPhone 4, iPhone 3GS running 3.1.3, and iPad), and then have 7-8 QA folks with 3 devices each, you can see that the devices get eaten up quite quickly. This isn't even considering all the devices a client may want to use for testing. I understand that Apple doesn't want people using AdHoc provisioning to get around the AppStore, but here is a case where we're doing the right thing and could run into issues.

Sixth, Xcode's ability to deploy an application to the AppStore is another area where it is problematic for the team. This requires that one of the developers does the submission. In theory, QA should do the upload once the build has been approved. The way around this, of course, is to use the Application Loader to handle it. However, the Application Loader application is half baked and very much geared to only working on one project. You have to go back through the setup wizard to change accounts (I've done uploads for 3 different projects).

While it is true that probably 95% of iPhone development is done by single developers, some of the top applications are done in teams and I think the teams are still trying to figure out the best way to handle development.

In my next post, I'll outline some of my ideas/practices for effectively working in teams on iPhone development.

Abstract Photo

My son loves playing with our camera and takes lots of pictures. Most of the pictures are blurry and we delete them. However, sometimes he takes a picture that looks pretty good. He was playing in my office a few months ago and took a picture of the mouse pad (a funky HP one; it was the largest one I could find with a smooth surface).

Click on the picture on the left to see a larger version.

Open source is not always the answer

I've been a huge fan of open source software for years and have contributed back to a few projects including the Palm OS Emulator and pilot-link. I've used a number of open source projects in my own applications and, of course, follow the license for attribution (I don't touch GPL code). Years ago when I was a lot greener, I used open source thinking that it must be perfect and treated the code at black boxes. This bit me on at least one project where we had to fix the code for years due to assumptions by the developer.

Now that I have more years under my belt and have done some of my own open source, I take a different view of open source. When I incorporate open source into my projects (with a few exceptions such as Sparkle that has been thoroughly tested), I closely examine the code and make sure I understand it. This takes time, but makes it less likely that I'll get bitten. I've seen a number of projects where developers find open source, shove it in an app, and call it a day without understanding what it does. I found one piece of code that completely went against what Apple has said to do in determining if a feature exists on a device; in another application, I found extremely complex networking code that may have been unnecessary (networking code is hard and the more complex it is, the harder it is to debug).

The main thing to realize with open source is that it was written by humans that can make mistakes and do! I have a large collection of open source code on my machine for reference (someday I'll catalog all that I've found) and use it to save time. I'm not saying that developers should reinvent the wheel for every piece of code, but they should be cautious when shoving code in their applications.