build.gradle

android {
    signingConfigs {
        release {
            storeFile = file('release.keystore')
            storePassword = 'actualReleasePassword'
            keyAlias = 'keyAliasName'
            keyPassword = 'actualReleaseKeyPassword'
        }
        debug {
            storeFile = file('debug.keystore')
            storePassword = 'actualDebugPassword'
            keyAlias = 'keyAliasName'
            keyPassword = 'actualDebugKeyPassword'
        }
    }
    compileSdkVersion 27
    buildToolsVersion '27.0.3'
    defaultConfig {
        applicationId "xyz.umarhussain.app"
        minSdkVersion 21
        targetSdkVersion 27
        versionCode 18
        versionName "1.0.9"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        multiDexEnabled true
        vectorDrawables.useSupportLibrary = true
        resConfigs "en"
    }
    buildTypes {
        debug {
            debuggable true
            useProguard true
            applicationIdSuffix '.debug'
            signingConfig signingConfigs.debug
        }
        release {
            debuggable false
            shrinkResources true
            minifyEnabled true
            useProguard true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            signingConfig signingConfigs.release
        }
    }
}

envbasedbuild.gradle

android {
    signingConfigs {
        release {
            storeFile = file(System.getenv('KEYSTORE_FILE_NAME'))
            storePassword = System.getenv('KEYSTORE_PASSWORD')
            keyAlias = System.getenv('KEYSTORE_ALIAS_NAME')
            keyPassword = System.getenv('KEYSTORE_KEY_PASSWORD')
        }
        debug {
            storeFile = file(System.getenv('KEYSTORE_FILE_NAME'))
            storePassword = System.getenv('KEYSTORE_PASSWORD')
            keyAlias = System.getenv('KEYSTORE_ALIAS_NAME')
            keyPassword = System.getenv('KEYSTORE_KEY_PASSWORD')
        }
    }
    compileSdkVersion 27
    buildToolsVersion '27.0.3'
    defaultConfig {
        applicationId "xyz.umarhussain.app"
        minSdkVersion 21
        targetSdkVersion 27
        versionCode 18
        versionName "1.0.9"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        multiDexEnabled true
        vectorDrawables.useSupportLibrary = true
        resConfigs "en"
    }
    buildTypes {
        debug {
            debuggable true
            useProguard true
            applicationIdSuffix '.debug'
            signingConfig signingConfigs.debug
        }
        release {
            debuggable false
            shrinkResources true
            minifyEnabled true
            useProguard true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            signingConfig signingConfigs.release
        }
    }
}

globalbuild.gradle

android {
    signingConfigs {
        release {
            if (project.hasProperty('RELEASE_STORE_FILE')) {
                storeFile file(RELEASE_STORE_FILE)
                storePassword RELEASE_STORE_PASSWORD
                keyAlias RELEASE_KEY_ALIAS
                keyPassword RELEASE_KEY_PASSWORD
            }
        }
        debug {
            if (project.hasProperty('DEBUG_STORE_FILE')) {
                storeFile file(DEBUG_STORE_FILE)
                storePassword DEBUG_STORE_PASSWORD
                keyAlias DEBUG_KEY_ALIAS
                keyPassword DEBUG_KEY_PASSWORD
            }
        }
    }
    compileSdkVersion 27
    buildToolsVersion '27.0.3'
    defaultConfig {
        applicationId "xyz.umarhussain.app"
        minSdkVersion 21
        targetSdkVersion 27
        versionCode 18
        versionName "1.0.9"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        multiDexEnabled true
        vectorDrawables.useSupportLibrary = true
        resConfigs "en"
    }
    buildTypes {
        debug {
            debuggable true
            useProguard true
            applicationIdSuffix '.debug'
            signingConfig signingConfigs.debug
        }
        release {
            debuggable false
            shrinkResources true
            minifyEnabled true
            useProguard true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            signingConfig signingConfigs.release
        }
    }
}

gradle.properties

# Global gradle properties
# CREDENTIALS
RELEASE_STORE_FILE=release.jks
RELEASE_KEY_ALIAS=umarproductionkey
RELEASE_STORE_PASSWORD=someComplexPassword
RELEASE_KEY_PASSWORD=someComplexPassword


# Project 2 jks
RELEASE_STORE_FILE=app2release.jks
RELEASE_KEY_ALIAS=app2atcompnay
RELEASE_STORE_PASSWORD=someComplexPassword
RELEASE_KEY_PASSWORD=someComplexPassword

keystore.properties

keyAlias=umarproductionkey
keyPassword=someComplexPassword
storeFile=../release.jks
storePassword=someComplexPassword

localproperties.build.gradle

def keystorePropertiesFile = file("../keystore.properties");
def keystoreProperties = new Properties()
keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
android {
    signingConfigs {
        release {
            storeFile = file(keystoreProperties['storeFile'])
            storePassword = keystoreProperties['storePassword']
            keyAlias = keystoreProperties['keyAlias']
            keyPassword = keystoreProperties['keyPassword']
        }
        debug {
            storeFile = file(keystoreProperties['storeFile'])
            storePassword = keystoreProperties['storePassword']
            keyAlias = keystoreProperties['keyAlias']
            keyPassword = keystoreProperties['keyPassword']
        }
    }
    compileSdkVersion 27
    buildToolsVersion '27.0.3'
    defaultConfig {
        applicationId "xyz.umarhussain.app"
        minSdkVersion 21
        targetSdkVersion 27
        versionCode 18
        versionName "1.0.9"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        multiDexEnabled true
        vectorDrawables.useSupportLibrary = true
        resConfigs "en"
    }
    buildTypes {
        debug {
            debuggable true
            useProguard true
            applicationIdSuffix '.debug'
            signingConfig signingConfigs.debug
        }
        release {
            debuggable false
            shrinkResources true
            minifyEnabled true
            useProguard true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            signingConfig signingConfigs.release
        }
    }
}