MOFCompare 🔬 provides a few cmdlets to help parsing and comparing DSC MOF files. This can be useful for all sorts of reason, the one that often gets brought up is the similarity it has to terraform plan feature. Comparing any two MOF related or otherwise, will provide an output of the added, removed and changed resources. Perhaps you need to monitor change over time, perhaps you need to know what your compilation has actually done or maybe you need to check the configuration between two seperate machines.
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🐱💻 MOFCompare is built and tested in Azure DevOps and is distributed via the PowerShell gallery.
MOFCompare is tested to be compatible with Windows PowerShell 5.1 and PowerShell Core 6.x.
Pester comes pre-installed with Windows 10, but we recommend updating, by running this PowerShell command as administrator:
Install-Module -Name MOFCompare -Forceor even better, install it into your profile
Install-Module -Name MOFCompare -Scope CurrentUser -ForceSometimes its nice to be able to read a MOF file with PowerShell in order to test things or validate during a build etc. The ConvertFrom-MOF will return a Dictionary with all the resources and their properties, nicely organised for you.
This is a really powerful feature which basic provides a similar feature to terraform plan but for DSC. You can know what resources have changed or been removed/added between any two MOFs. Its really useful for change management as well as for cleaning up resources after they've been removed.
# Import all the DSC Resources in the $env:PSModulePath into the cache to enable parsing of the schemas
Initialize-DscResourceCache
# you can use -ModulePathsToImport if you want to import specific modules
# The initial version requires you parse the MOFs seperately, but the next release will be able to automatically parse the file paths you pass
$ReferenceMof = ConvertFrom-MOF -Path .\first.mof
$DifferenceMof = ConvertFrom-MOF -Path .\second.mof
Compare-MOF -ReferenceMOF $ReferenceMof -DifferencingMOF $DifferenceMof -CompareProperties
# the CompareProperties which allows not only comparison of the resources that are added and removed, but also the properties of modified resourcesIf you're looking to know more about MOF and DSC generally, there is a great book by Ravikanth Chaganti Pro PowerShell Desired State Configuration.
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