Continuous Integration with TFS and ClickOnce

My current project is pretty fast-paced, so we need some good infrastructure to keep mundane concerns out of our way. As an advocate of eliminating cruft in the development process, I naturally wanted to implement a fully-automated continuous integration setup with building, testing, and publishing of the applications involved. Everybody's done this plenty of times with web applications, but it turns out that it's not quite so common with databases and ClickOnce applications. Since all three are included in this project, this is as good a time as any to figure out how to unify them all.

First some infrastructure... We're using Visual Studio 2013, SQL Server (different versions, so standardizing on 2008R2 as a target), and TFS. (I'm actually not certain about the TFS version. It's definitely latest or close to it, but not really being a "TFS guy" I don't know the specifics. It just works for what we need, I know that much. Beyond that, the client owns the actual TFS server and various controllers and agents.)

The entire solution consists of:

• A bunch of class libraries
• A WebAPI/MVC web application
• A WPF application
• A bunch of test projects
• A database project (schema, test data)

The goals for the build server are:

• A continuous integration build which executes on every check-in. (We're actually using gated check-ins too. I don't like gated check-ins, but whatever.)
• A test build which executes manually, basically any time we want to deliver something to QA.

And each build should:

• Compile the code
• Execute the tests
• Deploy the database
• Deploy the web application (with the correct config file)
• Deploy the ClickOnce WPF application (with the correct config file)

Some of this is pretty much out-of-the-box, some of it very much is not. But with a little work, it's just about as simple as the out-of-the-box stuff. So let's take a look at each one...

Compile The Code

This one is as out-of-the-box as it gets. I won't go into the details of creating a build in TFS, there's no shortage of documentation and samples of that and it's pretty straightforward. One thing I did do for this process, however, was explicitly define build configurations in the solution and projects for this purpose. We're all familiar with the default Debug and Release configurations. I needed a little more granularity, and knew that the later steps would be a lot easier with distinct configurations, so I basically deleted the Release configuration from everything and added a CI and a Test configuration. For now all of their settings were directly copied from Debug.

I used the default built template, and set each respective build (CI and Test) to build the solution with its configuration (Any CPU|CI and Any CPU|Test). Simple.

Execute The Tests

Again, this one is built-in to the TFS builds. Just enable automated tests with the build configuration and let it find the test assemblies and execute them.

Here's where I hit my first snag. I saw this one coming, though. See, I'm a stickler for high test coverage. 100% ideally. (Jason, if you're reading this... let it go.) We're not at 100% for this project (yet), but we are pretty high. However, at this early stage in the project, a significant amount of code is in the Entity Framework code-first mapping files. How does one unit test those?

The simplest way I found was to give the test assembly an App.config with a valid connection string and, well, use the mappings. We're not testing persistence or anything, just mapping. So the simplest and most direct way to do that is just to open a unit of work (which is just a wrapper for the EF context), interact with some entities, and simply dispose of the unit of work without committing it. If valid entities are added to the sets and no exceptions are thrown, the mappings worked as expected. And code coverage analysis validates that the mappings were executed during the process.

However, this is technically an integration test in the sense that EF requires the database to exist. It does some inspection of that database for the initial mappings. That's kind of what we're testing, so we kind of need a database in place. Perhaps we could write some custom mock that pretends to be a SQL database, but that sounds overly-complicated. For the simplest approach, let's just see if we can deploy the database as part of the build. The upside is that this will validate the database schema as part of the build anyway, which is just more automated testing. And automated testing is a good thing.

So...

Deploy The Database

A lot has changed in SQL Server projects between Visual Studio 2010 and Visual Studio 2012/2013. The project itself doesn't respect build configurations like they used to. But there's a new mechanism which effectively replaces that. When you right-click on the database project to publish it, you can set all of your options. Then you can save those options in an XML file. So it seemed sensible to me to save them in the project, one for each build configuration. (From then on, publishing from within Visual Studio just involves double-clicking on the XML file for that publish configuration.)

These XML files contain connection strings, target database names, any SQL command variables you want to define, and various options for deployment such as overwriting data without warning or doing incremental deploys vs. drop-and-create deploys. Basically anything environment-specific about your database deployments.

Now we need the TFS builds to perform a database publish. Since TFS builds are basically a TFS workflow surrounding a call to MSBuild, adding MSBuild arguments in the build configuration seemed like a simple way to perform this with minimal effort. First I included the Publish target for the build:

/t:Build /t:Publish

Then I also needed to specify to deploy the database and which publish file to use:

/t:Build /t:Publish /p:DeployOnBuild=true /p:SqlPublishProfilePath=CI.publish.xml

I'm actually not entirely sure at this point if all of those are necessary, but it works well enough. We're targeting both Build and Deploy for the build actions and setting a couple of project properties:

• DeployOnBuild - This is the one about which I'm not entirely certain. This setting doesn't exist in my project files in source control, but it seems to be the setting needed for the SQL Server project to get it to publish. (Or maybe it's used by one of the other projects by coincidence? This was all a bit jumbled together while figuring it out so that's certainly possible.)
• SqlPublishProfilePath - This is a setting in the SQL Server project file to tell it which of those XML files to use for its publish settings.

This executes as part of the MSBuild step and successfully deploys to the target CI database (or fails if the code is bad, which is just as useful a result), which means that the updated database is in place and ready by the time the TFS workflow reaches the test projects. So when the unit (and integration) tests execute, the CI database is ready for inspection by Entity Framework. All I needed to do was add an App.config to that particular unit test project with the connection string for the CI database.

But wait... What happens when we want to run those tests locally? If we change the connection string in the App.config then we run the risk of checking in that change, which would break the CI build for no particular reason. (Side note: I loathe when developers say "I'll just keep that change locally and not check it in." They always check it in at some point and break everybody else. Keep your team's environments consistent, damn it.) And App.configs don't have transforms based on build configuration like Web.configs do. (Side note: What the crap, Microsoft? Seriously, why is this not a thing? Web.config transforms have been around for, like, a billion years.)

We're going to need to include the correct configs for the WPF application deployments in a later step, so let's add a step...

Use A Different App.config

There are various solutions to perform transforms on an App.config. I tried a few of them and didn't much care for any of them. The most promising one was this tool called SlowCheetah, which came highly recommended by somebody with lots of experience in these sort of things. But for reasons entirely unknown to me, I just couldn't get the damn thing to work. I'm sure I was missing a step, but it wasn't obvious so I continued to look for other solutions.

We can use post-build xcopy commands, but we really don't want to do that. And based on my experience with projects which use that option I guarantee it will cause problems later. But one component of this solution does make sense... Keeping the App.configs in separate files for each build configuration. It'll likely be easier than trying to shoehorn some transform into the process.

After much research and tinkering, I found a really simple and sensible solution. By manually editing the items in the project file I can conditionally include certain files in certain build configurations. So first I deleted the Item entries for the App.config and its alternates from the csproj file, then I added this:

<ItemGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
  <None Include="App.config" />
</ItemGroup>
<ItemGroup Condition=" '$(Configuration)|$(Platform)' == 'CI|AnyCPU' ">
  <None Include="Configs\CI\App.config" />
</ItemGroup>
<ItemGroup Condition=" '$(Configuration)|$(Platform)' == 'Test|AnyCPU' ">
  <None Include="Configs\Test\App.config" />
</ItemGroup>

Notice the alternate App.config files in their own directories. The great thing about this approach is that Visual Studio doesn't respect the Condition attributes and shows all of the files. Which is great, because as a developer I want to be able to easily edit these files within the project. But when MSBuild comes along, it does respect the Condition attributes and only includes the files for the particular build configuration being built.

So now we have App.configs being included properly for each build configuration. When running tests locally, developers' Visual Studios will use the default App.config in the test project. When building/deploying on the server, MSBuild will include the specific App.config for that build configuration, so tests pass in all environments without manual intervention. This will also come in handy later when publishing the ClickOnce WPF application.

Next we need to...

Deploy The Web Application

Web application deployments are pretty straightforward, and I've done them about a million times with MSBuild in the past. There are various ways to do it, and I think my favorite involves setting up MSDeploy on the target server. The server is client-owned though and I don't want to involve them with a lot of setup, nor do I want to install things there myself without telling them. So for now let's just stick with file system deployment and we can get more sophisticated later if we need to.

So to perform a file system deploy, I just create a network share for the set up IIS site and add some more MSBuild arguments:

/p:PublishProfile=CI /p:PublishUrl=\\servername\sharename\

The PublishUrl is, obviously, the target path on the file system. The PublishProfile is a new one to me, but it works roughly the same as the XML files for the database publishing. When publishing the web application from within Visual Studio the publish wizard saves profiles in the Properties folder in the project. These are simple XML files just as before, and all we need to do here is tell MSBuild which one to use. It includes the environment-specific settings you'd expect, such as the type of deploy (File System in this case) or whether to delete existing files first, etc. (Now that I'm looking at it again, it also includes PublishUrl, so I can probably update that in the XML files and omit it from the MSBuild arguments. This is a work in progress after all.)

At this point all we need to do is...

Deploy The ClickOnce WPF Application

This one was the least straightforward of them all, mainly for one particular reason. A ClickOnce application is mostly useful in that it detects new versions on the server and automatically upgrades the client when it executes. This detection is based on the version number of what's deployed, but how can we auto-increment that version from within the TFS build?

It auto-increments, well, automatically when you publish from within Visual Studio. And most people online seem content with that. But the whole point here is not to manually publish, but rather to have a continuously deployed bleeding edge version of the application which can be actively tested, as well as have as simple and automated a QA deployment as possible (queue a build and walk away, basically). So we need TFS and/or MSBuild to auto-increment the build number. And they weren't keen on doing that.

So first thing's first, let's get it publishing at all before worrying about the build number. Much like with the publish profiles for the web application, this involved walking through the wizard once in Visual Studio just to get the project settings in place. Once in place, we can examine what they are in the csproj file and set them accordingly in the MSBuild arguments:

/p:PublishDir=\\servername\anothersharename\ /p:InstallUrl=\\servername\ anothersharename\ /p:ProductName=HelloWorldCI

The PublishDir and InstallUrl are for ClickOnce to know where to put the manifest and application files from which clients will install the application. The ProductName is just any unique name by which the application is known to ClickOnce, which would end up being its name in the Start Menu and the installed programs on the computer. (At this time I'm actually not sure how to get multiple different versions to run side-by-side on a client workstation. I'm sure it involves setting some other unique environment-specific value in the project, I'm just not sure what.)

So now clients can install the ClickOnce application from the network share, it has the correct App.config (see earlier), and everything works. However, at this time it doesn't detect new versions unless we manually update the version number. And we don't like "manually" around here. Researching and tinkering to solve this led me down some deep, dark rabbit holes. Colleagues advised and assisted, much Googling and Stack Overflowing was done, etc. I was very close to defining custom Windows Workflow actions and installing them on the server as part of the build workflow to over-write the csproj file after running it through some regular expressions. This was getting drastically over-complicated for my tastes.

While pursuing this approach, the big question was where I would persist the incrementing number. It needed to exist somewhere because each build would need to know what the value is before it can increment it. And I really didn't like the idea of putting it in a database somewhere just to support this one thing. Nor did I like the idea of storing it in the csproj file or any other file under source control because that would result in inconsistencies as gated check-in builds are queued. Then it hit me...

We have an auto-incrementing number on TFS. The ChangeSet number.

Now, I've never really edited the build workflow templates before. (Well, technically that's not entirely true. I did make some edits to one while specifically following steps from somebody else's blog post in order to build a SharePoint project before. But it was more SharePoint than TFS else and I had no idea what I was actually doing. So I didn't retain much.) And as such I didn't really know what capabilities were in place or how to reference/assign values. But with a little tinkering and researching, I put together something really simple.

First, I added a step to the build workflow template just before the MSBuild step. It was a simple Assign workflow item, and the value it was changing was MSBuildArguments (which is globally available throughout the workflow). Logically it basically amounts to:

MSBuildArguments.Replace("$ChangeSet$", BuildDetail.SourceGetVersion.Replace("C", String.Empty))

That is, it looks for a custom placeholder in the arguments list called $ChangeSet$ and replaces it with the ChangeSet number, which is also globally-available in the workflow as SourceGetVersion on the BuildDetail object. This value itself needs to have its "C" replaced with nothing, since ChangeSet numbers are prepended with "C". Now that I have the "persisted auto-incrementing" number, I just need to apply it to the project settings. And we already know how to set values in the csproj files:

/p:ApplicationRevision=$ChangeSet$ /p:MinimumRequiredVersion=1.0.0.$ChangeSet$

And that's it. Now when the ClickOnce application is published, we update the current version number as well as the minimum required version to force clients to update. Somewhere down the road we'll likely need to update the first three digits in that MinimumRequiredVersion value, but I don't suspect that would be terribly difficult. For now, during early development, this works splendidly.

So at this point what we have is:

• Explicit build configurations in the solution and projects
• XML publish profiles for the database project and the web application project
• Web.config transforms and App.config alternate files
• Conditional items in the csproj for the App.config alternate files, based on build configuration
• A workflow step to replace MSBuild argument placeholders with the ChangeSet number
• A list of MSBuild arguments:
• /t:Build /t:Publish /p:DeployOnBuild=true /p:PublishProfile=CI /p:SqlPublishProfilePath=CI.publish.xml /p:PublishUrl=\\servername\sharename\ /p:PublishDir=\\servername\someothersharename\ /p:InstallUrl=\\servername\someothersharename\ /p:ApplicationRevision=$ChangeSet$ /p:MinimumRequiredVersion=1.0.0.$ChangeSet$ /p:ProductName=HelloWorldCI

Replace "CI" with "Test" and we have the Test build. If we want to create more builds (UAT? Production?) all we need to do is:

• Create the build configurations
• Create the config files/transforms
• Create the publish profiles
• Set up the infrastructure (IIS site, network shares)
• Create a new TFS build with all the same near-default settings and just replace "CI" in the MSBuild arguments with the new configuration

And that's it. The result is a fully-automated continuous integration and continuous deployment setup. Honestly, I've worked in so many environments where a build/deploy consisted of a long, involved, highly manual, and highly error-prone process. Developers and IT support were tied up for hours, sometimes days, trying to get it right. What I have here, with a few days of research and what boils down to an hour or two of repeatable effort, is a build/deploy process which involves:

• Right-click on the build definition in TFS
• Select "Queue New Build"
• Go grab a sandwich and take a break

I love building setups like this. My team can now accomplish in two mouse clicks what other teams accomplish in dozens of man-hours.