How to replace variables of JSON file in Team Services?

Question

I'm stuck with a release variable substitution of an angular project. I have a settings.json file which I would like to replace some variables:

{ 
    test : "variable to replace"
}

I tried to find some custom task on the marketplace but all of the tasks seems to work only with xml files for the web.config.

Answer 1

I use the "Replace tokens" from the Marketplace https://marketplace.visualstudio.com/items?itemName=qetza.replacetokens

You define the desired values as variables in the Release Definition and then you add the Replace Tokens task and configure a wildcard path for all target text files in your repository where you want to replace values (for example: **/*.json). The token that gets replaced has configurable prefix and postfix (default are '#{' and '}#'). So if you have a variable named constr you can put in your config.json

{
   "connectionstring": "#{constr}#"
}

and it will deploy the file like

{
   "connectionstring": "server=localhost,user id=admin,password=secret"
}

Answer 2

The IIS Web App Deploy Task in VSTS Releases has JSON variable substitution under *File Transforms & Variable Substitution Options. Provide a list of json files and JSONPath expressions for the variables that need replacing

For example, to replace the value of ‘ConnectionString’ in the sample below, you need to define a variable as ‘Data.DefaultConnection.ConnectionString’ in the build/release definition (or release definition’s environment).

{
  "Data": {
    "DefaultConnection": {
      "ConnectionString": "Server=(localdb)\SQLEXPRESS;Database=MyDB;Trusted_Connection=True"
    }
  }
}