Android FeatureToggle library which helps to provide feature toggles on any flavors and manage it by different types: harcode, resources, remote, with local file storage and with debug panel activity.
FeatureToggle modules can be obtained from the github packages. It's also possible to clone the repository and depend on the modules locally. Just add the next repository to the dependency resolution manager:
dependencyResolutionManagement {
repositories {
// Use staging maven repository until the publish version on review
mavenCentral()
// or
maven {
url = uri("https://s01.oss.sonatype.org/service/local/repositories/releases/content/")
}
}
}
Connect feature-toggle library to your project to start using it:
implementation("io.github.ilyapavlovskii:feature.toggle:X.X.X")
If you want to use debug-panel, just add the next dependency:
implementation("io.github.ilyapavlovskii:debug.panel:X.X.X")
To start using FeatureToggle, first what you need is to define FeatureToggleContainer.
FeatureToggleContainer - that class uses to register all FeatureToggle instances that might be used in application.
Uses as a fallback, in the case when none of the configurations overloads the FeatureToggle values, the values will be taken from the container.
private val featureToggleContainer: FeatureToggleContainer = SimpleFeatureToggleContainer(
featureToggles = setOf(
SampleTitleFeatureToggle(
enabled = true,
title = "Sample FeatureToggle",
),
RestaurantInfoFeatureToggle(
mapVisible = true,
deliveryCostsVisible = true,
ratingVisible = true,
),
MenuItemFeatureToggle(
enabled = true,
gridCount = 3,
type = MenuItemFeatureToggle.PreviewType.HORIZONTAL_LIST,
addToCartAvailable = true,
)
)
).also { featureToggleContainer ->
// Don't forget to initialize `FeatureToggleContainerHolder`
FeatureToggleContainerHolder.init(featureToggleContainer)
}
//...
@Serializable
internal data class SampleTitleFeatureToggle(
val enabled: Boolean,
val title: String,
) : FeatureToggle {
override val toggleKey: FeatureToggleKey = FeatureToggleKey(KEY)
companion object {
private const val KEY = "sample_title"
}
}
@Serializable
internal data class RestaurantInfoFeatureToggle(
@SerialName("map_visible") val mapVisible: Boolean,
@SerialName("delivery_costs_visible") val deliveryCostsVisible: Boolean,
@SerialName("rating_visible") val ratingVisible: Boolean,
) : FeatureToggle {
override val toggleKey: FeatureToggleKey = FeatureToggleKey(KEY)
companion object {
private const val KEY = "restaurant_info"
}
}
@Serializable
data class MenuItemFeatureToggle(
@SerialName("enabled") val enabled: Boolean,
@SerialName("type") val type: PreviewType,
@SerialName("grid_count") val gridCount: Int,
@SerialName("add_to_cart_available") val addToCartAvailable: Boolean,
) : FeatureToggle {
override val toggleKey: FeatureToggleKey = FeatureToggleKey(KEY)
enum class PreviewType {
GRID,
VERTICAL_LIST,
HORIZONTAL_LIST,
;
}
companion object {
private const val KEY = "menu_item"
}
}
Don't forget to initialize the FeatureToggleContainerHolder. Holder uses to pass registered FeatureToggles between necessary components, e.g. FeatureToggleReader, FeatureToggleRegistrar and for DebugPanel.
FeatureToggleReader - defines FeatureToggle configuration override strategy.
private val json: Json = Json.Default
@XmlRes
private val defaultXmlConfigResource: Int = R.xml.default_feature_toggle_config
val xmlConfigReader = createXmlConfigReader(context)
val featureToggleReader = ChainFeatureToggleReader(
featureReaders = arrayOf(
// Internal XML file feature toggle
XmlFileFeatureToggleReader(
json = json,
xmlConfigReader = XmlFileConfigReader(),
xmlConfigFileProvider = DefaultConfigFileProvider(
applicationContext = context,
),
),
// Remote control
FirebaseFeatureToggleReader(
fetchTimeout = 60.seconds,
minimumFetchInterval = 12.hours,
json = json,
defaultConfigRes = defaultXmlConfigResource,
),
// Default resource file that might be overriden by flavor / buildType
ResourcesFeatureToggleReader(
json = json,
configReader = xmlConfigReader,
),
)
)
FeatureToggleReaderHolder.init(featureToggleReader)
Here we have 3 readers:
XmlFileFeatureToggleReader- reader with highest priority. If there is a debug file on the device, the reader looks for allFeatureTogglekeys and overrides its value. If key was found, the next readers will be skipped.FirebaseFeatureToggleReader- remote configuration reader. AnyFeatureTogglemight be overriden remotely. The system can be arbitrary. In our case it's Firebase. If key was found, the next readers will be skipped.
<?xml version="1.0" encoding="utf-8"?>
<defaultsMap>
<entry>
<key>menu_item</key>
<value>{
"enabled":true,
"type":"GRID",
"grid_count":2,
"add_to_cart_available":true
}
</value>
<key>restaurant_info</key>
<value>{
"map_visible": false,
"delivery_costs_visible": true,
"rating_visible":true
}
</value>
</entry>
</defaultsMap>
In the end, don't forget to initialize FeatureToggleReaderHolder. Uses as a default way to pass it to FeatureToggleRegistrar and DebugPanel.
FeatureToggleRegistrar - the main place to setup all FeatureToggles in the application.
object FeatureToggleRegistrarHolder {
private var featureToggleRegistrar: FeatureToggleRegistrar? = null
fun init(context: Context) {
featureToggleRegistrar = FeatureToggleRegistrar().setupFeatures()
}
fun featureToggleProvider(): FeatureToggleProvider =
requireNotNull(featureToggleRegistrar)
}
Then, to take any registered feature toggle, just call FeatureToggleRegistrarHolder.featureToggleProvider<SampleTitleFeatureToggle>()
val featureToggleProvider = FeatureToggleRegistrarHolder.featureToggleProvider()
val sampleTitleFeatureToggle: SampleTitleFeatureToggle = featureToggleProvider.get()
//....
if (sampleTitleFeatureToggle.enabled) {
Text(
modifier = Modifier.padding(8.dp),
text = sampleTitleFeatureToggle.title,
color = MaterialTheme.colorScheme.primary,
style = MaterialTheme.typography.titleLarge,
)
}
And initialize it in the Application class:
internal class FeatureToggleSampleApplication : Application() {
override fun onCreate() {
super.onCreate()
// FirebaseApp must be initialized before remote config reader
FirebaseApp.initializeApp(this)
FeatureToggleRegistrarHolder.init(context = this)
}
}
FeatureToggleRegistrarHolder
object FeatureToggleRegistrarHolder {
private val json: Json = Json.Default
@XmlRes
private val defaultXmlConfigResource: Int = R.xml.default_feature_toggle_config
private var featureToggleRegistrar: FeatureToggleRegistrar? = null
private val featureToggleContainer: FeatureToggleContainer = SimpleFeatureToggleContainer(
featureToggles = setOf(
SampleTitleFeatureToggle(
enabled = true,
title = "Sample FeatureToggle",
),
RestaurantInfoFeatureToggle(
mapVisible = true,
deliveryCostsVisible = true,
ratingVisible = true,
),
MenuItemFeatureToggle(
enabled = true,
gridCount = 3,
type = MenuItemFeatureToggle.PreviewType.HORIZONTAL_LIST,
addToCartAvailable = true,
)
)
)
fun init(context: Context) {
val xmlConfigReader = createXmlConfigReader(context)
val featureToggleReader = ChainFeatureToggleReader(
featureReaders = arrayOf(
XmlFileFeatureToggleReader(
json = json,
xmlConfigReader = XmlFileConfigReader(),
xmlConfigFileProvider = DefaultConfigFileProvider(
applicationContext = context,
),
),
FirebaseFeatureToggleReader(
fetchTimeout = 60.seconds,
minimumFetchInterval = 12.hours,
json = json,
defaultConfigRes = defaultXmlConfigResource,
),
ResourcesFeatureToggleReader(
json = json,
configReader = xmlConfigReader,
),
)
)
FeatureToggleContainerHolder.init(featureToggleContainer)
FeatureToggleReaderHolder.init(featureToggleReader)
featureToggleRegistrar = FeatureToggleRegistrar().setupFeatures()
}
private fun createXmlConfigReader(context: Context): ConfigReader = XmlConfigReader(
context = context,
xmlRes = defaultXmlConfigResource,
)
fun featureToggleProvider(): FeatureToggleProvider =
requireNotNull(featureToggleRegistrar)
}
If you want to use debug-panel, just add the next dependency:
implementation("by.bulba.feature.toggle:debug.panel:X.X.X")
Then, in your application will be available the next launcher: DebugPanel with the icon 
Copyright 2023 Ilia Pavlovskii
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
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