How can I transform a .properties file during a Gradle build?

Question

As part of a deploy task in Gradle, I want to change the value of a property in foo.properties to point to a production database instead of a development database.

I'd rather not replace the whole file outright, as it's rather large and it means we would have to maintain two separate versions that only differ on a single line.

What is the best way to accomplish this?

Answer 1

You can use the ant.propertyfile task:

    ant.propertyfile(
        file: "myfile.properties") {
        entry( key: "propertyName", value: "propertyValue")
        entry( key: "anotherProperty", operation: "del")
    }

Answer 2

You should be able to fire off an ant "replace" task that does what you want: http://ant.apache.org/manual/Tasks/replace.html

ant.replace(file: "blah", token: "wibble", value: "flibble")

Answer 3

Create a properties object, then create the file object with the targeted properties file path, load the file on the properties object with load, set the desired property with setProperty, and save the changes with store.

def var = new Properties() 
File myfile = file("foo.properties");

var.load(myfile.newDataInputStream())
var.setProperty("db", "prod")
var.store(myfile.newWriter(), null)