Azure-devops-docs: It is unclear how to do variable substitution on json file

[chillbilly79]

I came to this page looking for documentation on how to substitute variables (using a yaml build file) in my appsettings.json file from a variable group.

The part that is confusing to me is that in the "File transformations" section it says this is only supported for xml. Then later in the "Variable substitution" section it says both xml and json are supported but it appears that the xmlTransformationRules property is a required argument.

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• ID: 064f48ba-1c34-6422-5fe3-c3e88d2803c4
• Version Independent ID: c38f5761-4718-9aae-bc83-063257a78eb3
• Content: File Transform task - Azure Pipelines
• Content Source: docs/pipelines/tasks/utility/file-transform.md
• Product: devops
• Technology: devops-cicd
• GitHub Login: @RoopeshNair
• Microsoft Alias: ronai

[Seabizkit]

how do i see the result of the File Transform, its a task in release but can not see how i can see the results of the files which it has or has not applied to. FFS i really wish there were more examples of how 99% of people would be setting up builds and releases.

[multco-malan]

Yes I too would like to see an example using key vault values substituted into appsettings.json

It is confusing because the JSON supports the "dot" notation, e.g, Data.DefaultConnection.ConnectionString but the key vault does not support secrets containing "."

I'm looking for an example on setting up secrets in a Key Vault and then read those secrets in a release pipeline such that the appsettings.json gets modifed from:
"Twilio": { "SubaccountSID": "get from keyvault", "SID": "get from keyvault", "KEY": "get from keyvault" },
I've been able to set these values using pipeline variables named Twilio.SubaccountSID, Twilio.SID, Twilio.KEY but would rather have those values in a key vault.

[djbreen7]

I'm facing an issue in the same vain.

The part that is confusing to me is that in the "File transformations" section it says this is only supported for xml. Then later in the "Variable substitution" section it says both xml and json are supported but it appears that the xmlTransformationRules property is a required argument.

  - task: FileTransform@2
    inputs:
      enableXmlTransform: false
      folderPath: '$(System.DefaultWorkingDirectory)/**/*.zip'
      jsonTargetFiles: '**\*environment'

I'm getting the error Cannot perform XML transformations on a non-Windows platform, which doesn't really make sense, considering I have enableXmlTransforms: false. I've also tried omitting that value, but I get the same results.

As the OP has requested, please clarify.

[chillbilly79]

I'm facing an issue in the same vain.

The part that is confusing to me is that in the "File transformations" section it says this is only supported for xml. Then later in the "Variable substitution" section it says both xml and json are supported but it appears that the xmlTransformationRules property is a required argument.

  - task: FileTransform@2
    inputs:
      enableXmlTransform: false
      folderPath: '$(System.DefaultWorkingDirectory)/**/*.zip'
      jsonTargetFiles: '**\*environment'

I'm getting the error Cannot perform XML transformations on a non-Windows platform, which doesn't really make sense, considering I have enableXmlTransforms: false. I've also tried omitting that value, but I get the same results.

As the OP has requested, please clarify.

I did eventually get it to work like this:

 - task: FileTransform@1
    inputs:
      folderPath: '$(System.DefaultWorkingDirectory)'      
      fileType: json
      targetFiles: appsettings.json

[multco-malan]

I did find a working solution by utilizing the "Azure DevOps" section of this post:
https://medium.com/cheranga/transform-configurations-in-a-net-core-2-2-web-api-using-azure-devops-8febc8796713

[djbreen7]

Thanks @chillbilly79! That's working for me

[RobinZergiebel]

I'm using the solution provided by @chillbilly79 and receive a weird error message even though the JSON substitution works flawlessly:

My pipeline step:

• task: FileTransform@2
  condition: and(succeeded(), not(startsWith(variables['Build.SourceBranch'], 'refs/heads/feature/')))
  displayName: JSON substitution
  inputs:
  folderPath: '$(System.DefaultWorkingDirectory)/api/DfRias.Api/'
  fileType: json
  jsonTargetFiles: 'appsettings.json'

[tfks]

I got the changes already present message when directly targeting the source folder. The idea is that the build package is edited by this task so configuration is updated before test or deployment.

This worked for me (note the **/):

steps:

• task: FileTransform@1
  displayName: 'File Transform: appsettings.json'
  inputs:
  folderPath: '$(System.DefaultWorkingDirectory)'
  fileType: json
  targetFiles: '**/appsettings.json'

[sharpjs]

To prevent the error that @djbreen7 experienced:

Cannot perform XML transformations on a non-Windows platform

...you need to specify an empty xmlTransformationRules. This works against a Linux app service:

- task: FileTransform@2
  inputs:
    folderPath: $(Pipeline.Workspace)/path-to/my-package.zip
    jsonTargetFiles: appsettings.json
    xmlTransformationRules: '' # disabled

[RobinZergiebel]

I got the changes already present message when directly targeting the source folder. The idea is that the build package is edited by this task so configuration is updated before test or deployment.

This worked for me (note the **/):

steps:

• task: FileTransform@1
  displayName: 'File Transform: appsettings.json'
  inputs:
  folderPath: '$(System.DefaultWorkingDirectory)'
  fileType: json
  targetFiles: '**/appsettings.json'

Not directly targeting the source folder makes it easier to apply to other projects, but unfortunately I still get the same error :(.

Cheers,
Robin

[safoster88]

Just wanted to add that this has caused me hours of headache today.

Please update the Azure documentation with clear examples on how to do JSON variable substitution alone.

Or perhaps the better design would be to separate the 2 tasks entirely, XmlFileTransform, JsonFileTransform?

[AaronLS]

I'm just throwing my hat in the ring on this one to. The JSON Variable Substitution section doesn't actually show how you accomplish the substitution. It gives some preliminary information, skips how to actually setup the substitution, then goes right to showing a regular JSON config file which tells you nothing about how to setup substitution. A complete example would have a JSON example prior to substitution, then an example of setting up the substitution, then the resulting file. Showing only the resulting file doesn't provide any insight into how the substitution is setup. This could be caught by having an entry level dev go through the docs and try to accomplish these tasks themselves.

I've noticed legitimate unresolved issues have started being Closed due to inactivity. This is unfortunate. We've taken the time out of our busy days to point out these gaps in documentation. Simply because no one has acted on it, doesn't mean it's not an issue still. You're throwing away the effort we've put into coming here and trying to accurately describe issues. This is a long pattern going back to Microsoft Connect of disregarding valuable feedback.

You're just encouraging unnecessary noise in order for us to keep legitimate issues open. If no one actually took an action that would address the issue, don't close it.