Octopus Deploy Configuration Transforms

For the last couple of years, I’ve worked with Octopus Deploy as our main Deployment system. Prior to Octopus Deploy, we used custom made Powershell scripts that were built as extensions to TFS XAML builds.

The nice part of having all of our deployment logic in Powershell scripts is that we were able to reuse those scripts with Octopus Deploy. However, there are many features within Octopus Deploy which we were happy to ditch the scripts for and use what “came out of the box”. One of those places is Octopus Deploy’s Configuration Transforms.

ASP.NET (Web.Config)

Configuration Transforms are more of a legacy feature at this point, since they are designed to perform XML transforms for ASP.NET Web.Config files. ASP.NET Core’s appSettings.json files (and it’s corresponding Configuration system) are fine without performing environment specific transformations.

To use the Configuration Transforms feature, you only need to update your Deploy a Package step to use the Configuration Transforms feature and then setup a search pattern to find the files you want transformed.

ASP.NET Core (appSettings.json)

Of course, with ASP.NET Core you don’t really need to do configuration transforms anymore. However, if you do need to provide the functionality to transform appSettings.json files you can do that with a Powershell script.

Quick sidenote: Using Octopus Deploy, you can use the JSON Configuration Variables to perform substitutions in JSON files. However, the feature is designed to have the substitution values provided by Octopus variables.

Here’s a quick Powershell script which will:

• Uses the Microsoft.VisualStudio.Jdt nuget package (within a Transforms.Console.exe application, Thanks Jason La!) to transform the appSettings.json file.
• Removes the environment specifics transform files.