Android Build Variant Signing Config

Question

I have the following in my android app module build.gradle file.

android {

    defaultConfig {
        ...
    }

    signingConfigs {
        if (System.getEnv()['CIRCLE-CI']) { /* CI System */
            localMachine { /* CI System KeyStore file and properties. */
                ...
                keyAlias = "ABC"
            }
            playStore { /* CI System KeyStore file and properties. */
                ...
                keyAlias = "ABC"
            }
        } else { /* Local machine, not CI System. */
            localMachine { /* debug.keystore local file and properties. */
                ...
                keyAlias = "androiddebugkey"
            }
            playStore { /* debug.keystore local file and properties. */
                ...
                keyAlias = "androiddebugkey"
            }
        }
    }

    productFlavors {
        productOne {
            ...
        }
        productTwo {
            ...
        }
    }

    buildTypes {
        debug {
            ...
        }
        release {
            ...
        }
    }
}

/** This is where the problem is **/
android.applicationVariants.all { variant -> 
        if (variant.mergedFlavor.name == "productOne") {
            if (variant.buildType.name == "debug") {
                variant.signingConfig android.signingConfigs.localMachine
            } else if (variant.buildType.name == "release") {
                variant.signingConfig android.signingConfigs.playStore
            }
        } else if (variant.mergedFlavor.name == "productTwo") {
            if (variant.buildType.name == "debug") {
                variant.signingConfig android.signingConfigs.localMachine
            } else if (variant.buildType.name == "release") {
                variant.signingConfig null
            }
        }
    }
}

Expected output is as follows.

productOneDebug -> Sign with signingConfigs.localMachine
productTwoDebug -> Sign with signingConfigs.localMachine
productOneRelease -> Sign with signingConfigs.playStore
productTwoRelease -> Unsigned.

Actual output is as follows.

productOneDebug -> Signed with signingConfigs.localMachine
productTwoDebug -> Signed with signingConfigs.localMachine
productOneRelease -> Unsigned.
productTwoRelease -> Unsigned.

Why are Release apks always unsigned? The intention is to only have ProductTwo Release apk unsigned, but ProductOne Release apk should be signed based on the given configuration.

Answer 1

Apparently, this is what happens during the Gradle Sync.

Variant.signingConfig is a Over-written mechanism from both Flavor and Build-type, in the same order, based on whether a value exists.

productOne.signingConfig = playStore

productTwo.signingConfig = null

debug.signingConfig = localMachine

release.signingConfig = null

And the resulting Variants will be -

productOneDebug.signingConfig = productOne.signingConfig 

over-written by debug.signingConfig

productTwoDebug.signingConfig = productTwo.signingConfig

over-written by debug.signingConfig

productOneRelease.signingConfig = productOne.signingConfig 

over-written by release.signingConfig if exists.

productTwoRelease.signingConfig = productTwo.signingConfig 

over-written by release.signingConfig if exists.

Answer 2

I had a requirement like yours: I had two flavors (product-1 and product-2), and each one has different signing keystores. So, this is what I did, and hope it helps you.

The signing configs were declared as:

...
signingConfigs {
    'prod-1-release' {
        storeFile file('product-1-release.keystore')
        storePassword '...'
        keyAlias '...'
        keyPassword '...'
    }
    'product-1-debug' {
        storeFile file('product-1-debug.keystore')
        storePassword '...'
        keyAlias '...'
        keyPassword '...'
    }
    'product-2-debug'{
        storeFile file('product-2-debug.keystore')
        storePassword '...'
        keyAlias '...'
        keyPassword '...'
    }
    'product-2-release'{
        storeFile file('product-2-release.keystore')
        storePassword '...'
        keyAlias '...'
        keyPassword '...'
    }

}
...

And then, I defined my flavors as this:

flavorDimensions=["the_flavor"]
productFlavors{
    product-1 {
        dimension "the_flavor"
        ...
        buildTypes {
            release {
                minifyEnabled false
                proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
                signingConfig signingConfigs.'product-1-release'
            }
            debug {
                signingConfig signingConfigs.'product-1-debug
            }
    }
    product-2 {
        dimension "the_flavor"
        ...
        buildTypes {
            release {
                minifyEnabled false
                proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
                signingConfig signingConfigs.'product-2-release'
            }
            debug {
                signingConfig signingConfigs.'product-2-debug'
            }
        }
    }
}

All this is made in build.gradle file in :app level.

Hope this help you, and let the code be with you!