Is there a preprocessor for json files?

Question

I have some configuration files that I store the complex object values as serialized json. Currently there is a configuration file for each environment (localhost, dev, prod etc.) and for each installation by client. Most of the values are identically for the configurations between environments but not all. So for three environments and four clients I currently have 12 total files to manage.

If this were a web.config file there would be web.config transforms that would solve the problem. If this was c# I'd have compiler preprocessor directives that could be useed to substitute the different values based on the current build configuration.

Does anyone know of anything that works basically this way or have some good suggestion on tried and true ways to proceed? What I would like is to reduce the number of files down to a single instance for each installation that can suffice for each environment.

Answer 1

Configuration of configuration always seems a bit overdone to me, but you could use a properties file for the parts that change, and apache ant's <replace> task to do the substitutions. Something like this:

<replace 
    file="configure.json"
    propertyFile="config-of-config.properties">
  <replacefilter 
    token="@token1@" 
    property="property.key"/>
</replace>