App Store Entitlements, and the Crippling of an App

Because I’ve encountered this problem twice, I’m going to do a little write-up about it. As much for me as for the next person who encounters this problem. In a very un-Apple way, this process is very poorly documented and very un-intuitive from a user-developer standpoint. Everything that’s here, I’ve culled from Googling about aimlessly and finding on Stack Overflow. **Symptom: **You create a new app in Xcode with no changes and launch it. It launches just fine. You then go to the target summary settings and click “Enable Entitlements” and have an iCloud key/value store and or containers. Now you launch it and nothing happens. Nothing appears, but Xcode still thinks the app is running. **What’s Happening: **To understand what is happening, you have to go have a look in the Console application (note, the actual system Console.app, not the debug console in Xcode). Open that up and select “All Messages”. Look for something that looks like this: {% highlight bash %} 1/28/12 7:49:03.945 PM taskgated: killed [pid 43838] because its use of the com.apple.developer.ubiquity-container-identifiers entitlement is not allowed {% endhighlight %} What’s happening is that taskgated is killing your app because it’s not properly signed to use iCloud. And for some reason that is not entirely clear to me, the app being killed is not at all reported back to Xcode - Xcode thinks the app is running. So you just sit there waiting for something to happen with no clue that this sinister lurking background process has killed your app. How to fix it: There are two ways you can go from here to fix this. The first and easiest, if you are just turning on entitlements and aren’t intending to use iCloud, you can just remove the iCloud Key/Value Store and iCloud containers from the target summary. After doing this, it should work. But, if you are making an iCloud-enabled app, there’s a long list of things you need to do. First, understand that you need to be a paid member of Apple Developer Program. Log into ADC. Go to the Mac Dev Center, and the Developer Certificate Utility. Create an App ID by going to App IDs and clicking the Create App ID button in the upper right. Enter the name of your app and the bundle identifier. It usually looks something like “com.company.app”. Click Continue. Your app ID should be entered. Click the App ID you just entered, then click “Enable for iCloud.” Click save. Next, go to Certificates. If you haven’t created any certificates yet, click “Create Certificate” in the upper right and follow the directions. Note, you need both a development and an application certificate. Next, go to Systems. Be sure you’ve added your Mac (and, for good measure, any others you’ll use for development). Finally, go to Profiles. 1. Click Create Profile in the upper right. 2. Select "Development Provisioning Profile" 3. Give it a name. 4. Select the app you created in step 3. 5. Select the certificate you want to use. 6. Select the systems you want to use (I did all). 7. Click "Generate" It may take a few seconds, then it will give you a download. 8. Open the downloaded profile. It will open in the "profiles" preference pane (which doesn't seem to appear until you try to install a profile). Click install. Now, in Xcode: 1. Go to Window > Organizer. 2. Select "Devices" on the top, and "Provisioning Profiles" on the left. 3. At the bottom, select "Automatic Device Provisioning" at the bottom, and click "Refresh". If you've never done this before, you'll need to log in with your ADC username and password. 4. Give it a second, it should pull in your profiles. 5. Go to your project, select your app target and select "Build Settings." Scroll down to "Code Signing." You may need to go to "All" from "Basic" in the predicate selector. 6. Under Code Signing Identity, select the dev profile you just created. Note: don't use the wildcard one - it doesn't seem to work. Whew. Now, if everything went as planned (and you sacrificed a goat to Tim Cook and Tim found your sacrifice pleasing) you should be able to launch your app with no errors. But help! I got a weird failure on build! If you get a failure on build that looks like this: {% highlight bash %} Command /usr/bin/codesign failed with exit code 1 {% endhighlight %} Then it is possible that your developer certificate is set to “Always Trust” in Keychain. It needs to be set to “System defaults” for reasons that escape me entirely. Note, this may not be entirely accurate and may even be cargo-cultish. But I’ve encountered this “issue” twice now (once in December, and once now) so I decided to write down my steps so that, in a few months when this befuddles me again, I’ll know where to look for the answer.

So today, out of nowhere, Xcode 4 finally landed as an official release. After seemingly forever in beta, and me quipping more than once about it’s similarity to Duke Nukem Forever, Apple finally pulled the trigger and released it. But something changed. Xcode now has a price. And that has left me, as both a Mac user and a Mac developer, with a lot of questions. It’s either $4.99 if you’re not a registered, paid Apple developer, or free if you are a registered, paid Apple developer (with all its $99 per year price tag glory). Supposedly there’s some crazy accounting reason that they have to charge for it. This, of course, leaves open the possibility that Xcode will soon be free again once OS X 10.7 arrives. But, it also leaves open the possibility that Xcode will no longer be distributed with OS X and will always have a price tag. It may not even stay $4.99. It may be $49.99 or $499.99. There are additional questions, too. Does this mean that Apple is still distributing Xcode as a bundle with GNU GCC? Because there are things (such as MacPorts) that rely on the underlying foundation provided by the developer bundle that don’t actually use Xcode. Before, those were completely free. Now, they cost $4.99 unless they have split the underlying compiler from the IDE. And if they are still distributing it with GCC, that leads to all kinds of crazy interesting licensing questions. But I think the worst part is that there is now a barrier to entry, however low, to being a developer on a platform that is already a minority in market share. I can’t understand how Apple potentially believes that it is good and right to trade short term profits for long term growth in the number of potential developers. For the future of the Mac platform, I sure hope this isn’t their line of reasoning. So, let me tell you a little story. My first dabbling in programming came courtesy of QuickBASIC back in the MS-DOS and Windows 3.1 days. This was the late 80s or early 90s, so I would have been 10 or 11 at the time. I stumbled across the Qbasic environment included with MS-DOS by accident and found Nibbles. And, after playing it, I discovered that I could change things by making changes to the strange text presented on the screen. I could change colors and speeds. But it would be a couple of years before I really understood what I was doing. When Windows 95 came out (and along with it, Visual Basic 4), I talked my parents into getting me a copy. I don’t remember how much it cost but it was probably a lot because it was one of the few Christmas presents I got that year. But boy did I run with it. I’ve periodically felt guilty over that expense because I didn’t actually make anything really useful with it, but it was instrumental in furthering my education. Now I could do things on my computer far beyond what poor ol’ Qbasic was capable of. So I wrote lots of silly little programs. I put together a “family newsletter” one year that was installed and ran as a piece of software. I was pretty proud of that. I even wrote some software for my high school as part of a software development and AP Computer Science courses. Eventually, I would move on to other things. Other versions of Visual Basic, Java, C, a brief foray into LISP and Forth-based languages for programming MUDs, and eventually web programming. First in Perl, then in PHP. I even landed my first paying programming job while still in high school, writing applications for a local transit contractor. At first, these were Visual Basic applications. But by the time I left (August of 2000) everything was going to the web and so were we. But I can trace everything - my entire career, and my consuming passion for software engineering - back to Qbasic and Nibbles. A silly little game about a block snake, and a free development environment included with the operating system. Had I not stumbled on Qbasic and Nibbles, there’s a chance I would never have been a developer. This is not about $4.99. I spend more on coffee in a week than that. My worry is about that 11 year old kid out there somewhere who may never get the opportunity to stumble across Xcode or the sample applications in /Developer and realize the raw power they possess. This is an area where Apple, a company with billions in cash on hand, should be happy to show a loss. It would be to the benefit of their platform, both now and in the future. One of the great benefits of the Mac platform has been it’s low barriers of entry to developers. Sure, one could argue that the hardware is more expensive (and I could counter-argue that, for the quality of the equipment you are getting a bargain), but the development tools have always been freely available online and included with the machine. You could dabble in programming to your heart’s content. Sure, if you want to put something in the app store(s), you had to pay for admission, but there was nothing stopping you from getting all the way to that point, or even distributing your creations on your own. But this new trend of charging for the development tools - even if it is a paltry sum - sends, to me, a worrying signal about the course Apple intends to tread. They’ve now moved the gate from the last step to the first step. It’s a course that Microsoft, as above, once tread. Microsoft? They now give away a version of Visual Studio for free.

Over the weekend, I was having some hard drive issues. While I think I fixed the issues, I’ve been keeping a close eye on my console (Console.app) to look for any hints that the issues are more major than those that can be repaired by Disk Utility. However, while watching my console, I noticed something: there are a LOT of spammy Mac apps out there! Most Mac/Objective-C developers are aware of the NSLog() function, which, while in an Xcode environment, outputs data to the Xcode console. It’s usually one of the first things a new developer learns about and it’s very useful for debugging. What many developers may not realize is that NSLog() continues to output data to the system logs even when the app is not being run from within Xcode. As a result, the console fills up with messages that don’t mean a whole lot to people looking at the console. Now, I don’t want to come across as saying you should never use NSLog() outside of Xcode. There are times when outputting debug data to the console is fine. But some of the things I see are people echoing objects into the log or short text strings that are obviously method names. These aren’t helpful to people looking at the console and, arguably, aren’t helpful to a developer once an app is in the wild. Once your app is in the wild, data in the logs should indicate error conditions in your app. NSLog() is fine for debugging in Xcode, but you should be careful to remove them when you’re done. A good question I ask myself before leaving an NSLog() in place is, “if a user filed a support request with this data, would it help me fix their problem?” Most of the time, the answer is no. So before releasing an app, do a quick search in your project for all uses of NSLog() and evaluate whether they are really needed.