First, place the respective google_services.json for each buildType in the following locations:
app/src/debug/google_services.json
app/src/main/google_services.json
Now, let’s whip up some gradle tasks in your :app’s build.gradle to automate moving the appropriate google_services.json to app/google_services.json
task switchToDebug(type: Copy) {
description = 'Switches to DEBUG google-services.json'
from "src/debug"
include "google-services.json"
into "."
}
task switchToRelease(type: Copy) {
description = 'Switches to RELEASE google-services.json'
from "src/release"
include "google-services.json"
into "."
}
Great — but having to manually run these tasks before you build your app is cumbersome. We would want the appropriate copy task above run sometime before :assembleDebug or :assembleRelease is run. Let’s see what happens when :assembleRelease is run:
Zaks-MBP:my_awesome_application zak$ ./gradlew assembleRelease
Parallel execution is an incubating feature.
.... (other tasks)
:app:processReleaseGoogleServices
....
:app:assembleRelease
Notice the :app:processReleaseGoogleServices task. This task is responsible for processing the root google_services.json file. We want the correct google_services.json to be processed, so we must run our copy task immediately beforehand.
Add this to your build.gradle. Note the afterEvaluate enclosing.
afterEvaluate {
processDebugGoogleServices.dependsOn switchToDebug
processReleaseGoogleServices.dependsOn switchToRelease
}
Now, anytime :app:processReleaseGoogleServices is called, our newly defined :app:switchToRelease will be called beforehand. Same logic for the debug buildType. You can run :app:assembleRelease and the release version google_services.json will be automatically copied to your app module’s root folder.
https://medium.com/google-cloud/automatic-per-variant-google-services-json-configurations-with-gradle-d3d3e40abc0e