Devops

Config file transforms with Azure Devops

For a long time now our primary CI setup has been based around Team City and Octopus deploy, but as reliable as it is there are things I don't like about it:

  1. It's not a SASS setup meaning there's a VM to occassionaly think about and updates to install. While Octopus is now availiable as a SASS option, Team City is not and moving Octopus will only solve half the problem.
  2. That VM they both sit on every so often gets and issue with it's hard disk being full.
  3. It's complicated to recommend the same setup to clients. You end up having to go through multiple things they need to buy which then require some installation and ongoing maintenance. Ideally we would have a setup thats easy for them to replicate and own themselves with minimal maintenance.

So when we took over a site recently that typically came with no existing CI setup in place, I decided to take a look at using Azure Devops instead. You can use Azure Devops with Octopus Deploy but as it claims to be able to manage releases as well as builds we went for doing the whole thing just in Azure Devops.

Getting a build set up was relatively straight forward so I'm going to skip past that bit, but in short we ended up with a build that will create a web deploy package and publish it as an artifact. Typical msbuild type stuff.

File transforms and variable substitution

The first real tricky point came with replacing variables in config files during a release to each envrionment. We were using the IIS Web App Deploy task to deploy the application to IIS on a VM (no new Azure Web App Services in this setup :( as I said we took over the site and this was just to get automated deploys of what they already have). A simple starting point with this is some built in functionality for XML Variable Substituion in the IIS Web App Deploy task.

Quite simply you can add all your varibles to the variable list, set the scope for which envrionment you want it to apply to and the during the deploy they are replaced in your config. Unlike some tag replacement tools I've used in the past this one actually uses the name of the connecting string or app setting you need to set, so if you need to set a connection string named web, the variable name will be web.

This is also where my problem stated. The description for what XML variable substitution does is:

This was a Sitecore solution and for Sitecore most of your config settings are in Sitecores own Sitecore section of the config file. So in other words the connection string will get updated but the rest won't.

Parameter and SetParameter XML files

My next issue was trying to find a solution is actually quite hard. Searching for this problem either gave me a lot of results for setups using ARM templates (as I said, this was a solution we took over and that kind of change is not on the agenda), or you just get the easy bit above. Searching for Sitecore and Azure Devops also leads you to a lot of results on a cloud infrastructure setup (again not what we're doing here, at least in the short term). Everything that was coming up felt far more complicated than the solution should be.

However the documentation on the XML variable substitution did have one interesting sentance.

A parameters.xml file isn't something I've used before which makes this sentance a bit cryptic. The first half says I can do what I want with an xml file, but the second half says I'll need something else to actually do it.

After a bit of research this all comes back to web deploy. When you do a build that outputs a web deploy package, you get 5 files.

A zip file containing the actual site, a command file which has the script to do the deploy and a set parameters file which is used to set config variables during the deploy. The others aren't so imporant.

To have different config set on different envrionments you just need to edit the set parameters file. But first you need to have the parameter in the set parameters file so that you can actually change it and this is where the parameters.xml file comes in.

Creating the parameter files

Add a file called parameters.xml file to the root of your project and then add parameters as follows.

<?xml version="1.0" encoding="utf-8" ?>
<parameters>
<parameter name="DataFolderLocation" defaultvalue="#{dataFolder}">
  <parameterEntry kind="XmlFile" scope="App_Config\\Include\\Z.Project\\DataFolder\.config$" match="/configuration/sitecore/sc.variable[@name='dataFolder']/patch:attribute/text()" />
</parameter>
</parameters>

Some important parts:

default value - The value that the config setting will get set to

scope - The path to the file containing the setting

match - An XPath expression for find the part of the config file to update

Once you have this the build will start producing a SetParameters.xml file containing the extra parameters.

<?xml version="1.0" encoding="utf-8"?>
<parameters>
<setParameter name="IIS Web Application Name" value="Default Web Site/SiteCore.Website_deploy" />
<setParameter name="DataFolderLocation" value="#{dataFolder}" />
</parameters>

Note: I've set the value to be something I intend to replace in the release process.

Replacing the tokens

With our SetParameters.xml file now contining all the config we need to update, we need a step in the release process that will replace all the tokens with the correct values.

To do this I used a replaced tokens task https://marketplace.visualstudio.com/items?itemName=qetza.replacetokens

Config options need to be set for:

Root Directory - Path to the folder containing the SetParameters.xml file

Target files - A list of files to have replacements done in. In our case this was SiteCore.Website.SetParameters.xml

Token prefix - The prefix on tokens to be search for. Ours was #{

Token suffix - The suffix to denote the end of a token. Ours was }

Lastly in the IIS Web App Deploy step the SetParameters file needed to be selected and the new variables added to the variable list in Azure Devops. The variable names need to be called the bit between your prefix and suffix. i.e. #{datafolder} would be called datafolder.

If you don't set the variables then the log's will show warning for each one it couldn't find.

2019-09-24T17:17:21.6950466Z ##[section]Starting: Replace tokens in SiteCore.Website.SetParameters.xml
2019-09-24T17:17:23.9831695Z ==============================================================================
2019-09-24T17:17:23.9831783Z Task         : Replace Tokens
2019-09-24T17:17:23.9831816Z Description  : Replace tokens in files
2019-09-24T17:17:23.9831861Z Version      : 3.2.1
2019-09-24T17:17:23.9831891Z Author       : Guillaume Rouchon
2019-09-24T17:17:23.9831921Z Help         : v3.2.1 - [More Information](https://github.com/qetza/vsts-replacetokens-task#readme)
2019-09-24T17:17:23.9831952Z ==============================================================================
2019-09-24T17:17:27.2703037Z replacing tokens in: C:\azagent\A1\_work\r1\a\PublishBuildArtifacts\SiteCore.Website.SetParameters.xml
2019-09-24T17:17:27.3133832Z ##[warning]variable not found: dataFolder
2019-09-24T17:17:27.3179775Z ##[section]Finishing: Replace tokens in SiteCore.Website.SetParameters.xml

With all this set our config has it's variables configured within Azure Devops for each environment,

Bundling with Gulp in TeamCity

Like most, our front end developers write CSS in LESS or SASS and then use Gulp to compile the result. This is great but up until recently both the compiled and source style files would end up in our source control repository.

While this isn't a major issue it was more of an annoyance factor when doing a merge that the compiled file would need to be merged as well as the source files. Any conflicts in bundled/minified files also can become problematic to solve. As well as this it also just seems wrong to have both files in a repo, effectively duplicating the file. After all we wouldn't put compiled dll's into a repo with their source.

Our solution was to get the build server to start running the gulp tasks to produce the bundled files.

Step 1 - Install Node on the build server

To start we need NodeJS installed on the build server. This allows extensions to be installed via NPM (Node Package Manager), it's a similar thing to NuGet,

Step 2 - Install the TeamCity plugin for NodeJS

To add built steps for Node and Gulp we need to install a plugin to make them available. Lucking there is one that does such a thing here https://github.com/jonnyzzz/TeamCity.Node

The actual build of the plugin you can download from Jetbrains team city here https://teamcity.jetbrains.com/viewType.html?buildTypeId=bt434. Just login as guest and then download the latest zip from the artifacts of the last build.

To install the plug you need to copy the zip to Team City's plugin folder. For me this was C:\ProgramData\JetBrains\TeamCity\plugins, if your having trouble finding your's just go to Administration > Global Settings in Team City and it will tell you the data directory. The plugin folder will be in there.

Restart the TeamCity server and the plugin should now show under Administration > Plugins List

Step 3 - Add a NPM Setup build step

The NPM step with a command of install will pick up dependencies and get the files.

Step 4 - Add a Gulp build step

 

In your gulp step add the path to the gulp file and the tasks in your gulp file that need to be run. I'm using a gulp file that our front end devs had already created for the solution that contained as task for bundling css and another for bundling js.

Step 5 - Including bundled files in a MSBuild

As the bundled files are no longer included in our Visual Studio solution it also means that they arn't included in the set of files which will be included in a publish when MSBuild runs.

To overcome this update the .csproj file with a Target with BeforeTargets set to BeforeBuild and list your bundled files as content. In my example I'm included the whole Content\bundles folder

<Target Name="BundlesBeforeBuild" BeforeTargets="BeforeBuild"> 
<ItemGroup> 
<Content Include="Content\bundles\**" /> 
</ItemGroup> 
</Target&gt;

Adding Build Statuses to Pull Requests with TeamCity and GitHub

I'm always looking for ways to improve our build server setup and improve our overall efficiency. So a recent change I've made is to get Team City to start building pull requests and pushing the resulting status back to GitHub.

This improves our dev flow by eliminating the need to do any testing on a pull request if we can already see it will fail a build. Previously someone doing a code review would only find out once they've checked out the change and built it locally, or even worse after approving the request and then breaking the build.

What's particularly good with this setup, is it's testing the resulting merge rather than just the branch being merged in.

Team City Setup

As this is covering a different scenario to our normal build processes which are focused on preparing a build version to be deployed, I set this up as a second build configuration on our projects.

Version Control Settings Root (VCS Root)

The VCS Root needs to be configured to fetch each pull request that is creating in GitHub. To do this, you will need to add a Branch specification which will tell Team City to monitor additional branches rather than just the default branch specified.

I'm using the branch specification +:refs/pull/(*/merge) .

This syntax is telling Team City to monitor references to pull for pull request, the * refers to any pull request, and the merge indicates that we only want to resulting merge of the pull request.

When you create a pull request in GitHub, this merge reference is automatically created for what the resulting merge would look like.

In the projects list, builds will now get labels indicating what they were for:

Build Steps

I created my build configurations by duplicating the existing ones we have that take care of creating builds to be passed onto Octopus Deploy for release. If you do this, it's important to remember to disable all the steps you no longer need.

The less steps you have the quicker your build will run and the quicker the pull request will be updated with a status. Ideally you want the process to finish before someone starts doing a code review! Steps like running Inspections may prove counter productive if the builds are never finished on time.

Triggers

Having a build running automatically for your releases can be a drain on server resources, particularly if you never have any intention of actually doing a deploy for most of them. For this reason our builds are set to manual.

However for statuses to be of any use, they're going to need to be running automatically so that the status is ready for the code reviewer, so we need to add a VCS Trigger.

Build Features

To get Team City to start posting status updates back to GitHub we need to add a build feature. If your on a version of TeamCity prior between 7.1 and 10 then there is a plugin you can grab here https://github.com/jonnyzzz/TeamCity.GitHub. If your on a newer version of TeamCity. i.e. 10+ then the build feature is now built in and is called Commit status publisher. The built in version also has support for Bitbucket, Gerrit, GitLab, JetBrains Upsource and Visual Studio Team Services.

Add the build feature and fill in the config settings.

And that's it. Your pull requests will now automatically build and have the status sent back to GitHub.

Not only will you be able to see this status in GitHub, you'll also be able to click a details link to see the build. Useful in the event that it's failed and you want to see why.