Streamlines remote configuration management, offering flexible syntax for declaring configuration elements, multiple data sources, and debugging capabilities. Supports feature-specific configurations with logging and interception functionalities.
Konfeature is a powerful Kotlin Multiplatform library for managing remote configuration in your applications. It provides a clean, declarative API for working with feature flags and configuration elements across Android, iOS, and JVM platforms.
Working with remote configuration has become a standard part of the development process for almost any application. Depending on the complexity of the application, several requirements for such functionality may arise, including:
We have made every effort to meet all these requirements in the development of Konfeature.
Konfeature is a Kotlin Multiplatform library with support for:
| Platform | Status | Targets |
|---|---|---|
| Android | ✅ Fully Supported | JVM (via Kotlin/JVM) |
| iOS | ✅ Fully Supported | arm64, x86_64, simulator arm64 |
| JVM | ✅ Fully Supported | Java/Kotlin applications |
repositories {
mavenCentral()
}For Gradle (Kotlin Multiplatform Project):
kotlin {
sourceSets {
commonMain.dependencies {
implementation("com.redmadrobot.konfeature:konfeature:<version>")
}
}
}For Gradle (Single Platform):
dependencies {
implementation("com.redmadrobot.konfeature:konfeature:<version>")
}Defines a set of configuration elements, where each element is defined using a delegate. There are two types of delegates:
by toggle(...) - used for elements of type Boolean
by value(...) - used for elements of any other typeclass ProfileFeatureConfig : FeatureConfig(
name = "profile_feature_config",
description = "Config of features for profile usage"
) {
val isProfileFeatureEnabled: Boolean by toggle(
key = "profile_feature",
description = "show profile entry point for user",
defaultValue = false,
)
val profileFeatureTitle: String by value(
key = "profile_feature_title",
description = "title of profile entry point button",
defaultValue = "Feature number nine",
sourceSelectionStrategy = SourceSelectionStrategy.Any
)
val profileButtonAppearDuration: Long by value(
key = "profile_button_appear_duration",
description = "duration of profile button appearing in ms",
defaultValue = 200,
sourceSelectionStrategy = SourceSelectionStrategy.Any
)
}The configuration requires specifying:
name - the name of the configurationdescription - a detailed description of the configurationEach configuration element requires specifying:
key - used to retrieve the value of the element from a Source
description - a detailed description of the elementdefaultValue - used if the value cannot be found in a Source
sourceSelectionStrategy - the strategy for selecting a Source using SourceSelectionStrategy
After that, you need to register the configuration in Konfeature:
val profileFeatureConfig: FeatureConfig = ProfileFeatureConfig()
val konfeatureInstance = konfeature {
register(profileFeatureConfig)
}Similarly, you can add multiple configurations, for example, for each module, when organizing multi-modularity by features.
An abstraction over the value source for configuration elements.
public interface FeatureSource {
public val name: String
public fun get(key: String): Any?
}name - source nameget(key: String) - logic for getting values by key
Example implementation based on FirebaseRemoteConfig:
class FirebaseFeatureSource(
private val remoteConfig: FirebaseRemoteConfig
) : FeatureSource {
override val name: String = "FirebaseRemoteConfig"
override fun get(key: String): Any? {
return remoteConfig
.getValue(key)
.takeIf { source == FirebaseRemoteConfig.VALUE_SOURCE_REMOTE }
?.let { value: FirebaseRemoteConfigValue ->
value.getOrNull { asBoolean() }
?: value.getOrNull { asString() }
?: value.getOrNull { asLong() }
?: value.getOrNull { asDouble() }
}
}
private fun FirebaseRemoteConfigValue.getOrNull(
getter: FirebaseRemoteConfigValue.() -> Any?
): Any? {
return try {
getter()
} catch (error: IllegalArgumentException) {
null
}
}
}After that, you need to add the Source in Konfeature:
val profileFeatureConfig: FeatureConfig = ProfileFeatureConfig()
val source: FeatureSource = FirebaseFeatureSource(remoteConfig)
val konfeatureInstance = konfeature {
addSource(source)
register(profileFeatureConfig)
}Similarly, you can add multiple sources, for example, Huawei AppGallery, RuStore, or your own backend.
You can configure the retrieval of an element's value from the source more flexibly by using the sourceSelectionStrategy parameter:
val profileFeatureTitle: String by value(
key = "profile_feature_title",
description = "title of profile entry point button",
defaultValue = "Feature number nine",
sourceSelectionStrategy = SourceSelectionStrategy.Any
)Where sourceSelectionStrategy filters the available data sources.
public fun interface SourceSelectionStrategy {
public fun select(names: Set<String>): Set<String>
public companion object {
public val None: SourceSelectionStrategy = SourceSelectionStrategy { emptySet() }
public val Any: SourceSelectionStrategy = SourceSelectionStrategy { it }
public fun anyOf(vararg sources: String): SourceSelectionStrategy = SourceSelectionStrategy { sources.toSet() }
}
}The select(...) method receives a list of available Source names and returns a list of sources from which the configuration element can retrieve a value.
For most scenarios, predefined implementations will be sufficient:
SourceSelectionStrategy.None - prohibits taking values from any source, i.e., the value specified in defaultValue will always be usedSourceSelectionStrategy.Any - allows taking values from any sourceSourceSelectionStrategy.anyOf("Source 1", ... ,"Source N") - allows taking values from the specified list of sources[!IMPORTANT] By default,
SourceSelectionStrategy.Noneis used!
Allows intercepting and overriding the value of the element.
public interface Interceptor {
public val name: String
public fun intercept(valueSource: FeatureValueSource, key: String, value: Any): Any?
}name - the name of the interceptorintercept(valueSource: FeatureValueSource, key: String, value: Any): Any? - called when accessing the element with key and value from valueSource(Source(<name>), Interceptor(<name>), Default), and returns its new value or null if it doesn't changeExample of implementation based on DebugPanelInterceptor:
class DebugPanelInterceptor : Interceptor {
private val values = mutableMapOf<String, Any>()
override val name: String = "DebugPanelInterceptor"
override fun intercept(valueSource: FeatureValueSource, key: String, value: Any): Any? {
return values[key]
}
fun setFeatureValue(key: String, value: Any) {
values[key] = value
}
fun removeFeatureValue(key: String) {
values.remove(key)
}
}After that, you need to add the Interceptor in Konfeature:
val profileFeatureConfig: FeatureConfig = ProfileFeatureConfig()
val source: FeatureSource = FirebaseFeatureSource(remoteConfig)
val debugPanelInterceptor: Interceptor = DebugPanelInterceptor()
val konfeatureInstance = konfeature {
addSource(source)
register(profileFeatureConfig)
addInterceptor(debugPanelInterceptor)
}Similarly, you can add multiple interceptors.
public interface Logger {
public fun log(severity: Severity, message: String)
public enum class Severity {
WARNING, INFO
}
}The following events are logged:
Get value 'true' by key 'profile_feature' from 'Source(name=FirebaseRemoteConfig)'
Source or Interceptor returns an unexpected type for key
Unexpected value type for 'profile_button_appear_duration': expected type is 'kotlin.Long', but value from 'Source(name=FirebaseRemoteConfig)' is 'true' with type 'kotlin.Boolean'
Example of implementation based on Timber:
class TimberLogger: Logger {
override fun log(severity: Severity, message: String) {
if (severity == INFO) {
Timber.tag(TAG).i(message)
} else if (severity == WARNING) {
Timber.tag(TAG).w(message)
}
}
companion object {
private const val TAG = "Konfeature"
}
}After that, you need to add the Logger in Konfeature:
val profileFeatureConfig: FeatureConfig = ProfileFeatureConfig()
val source: FeatureSource = FirebaseFeatureSource(remoteConfig)
val debugPanelInterceptor: Interceptor = DebugPanelInterceptor()
val logger: Logger = TimberLogger()
val konfeatureInstance = konfeature {
addSource(source)
register(profileFeatureConfig)
addInterceptor(debugPanelInterceptor)
setLogger(logger)
}Konfeature contains information about all registered FeatureConfig in the form of spec:
public interface Konfeature {
public val spec: List<FeatureConfigSpec>
public fun <T : Any> getValue(spec: FeatureValueSpec<T>): FeatureValue<T>
}This allows you to obtain information about added configurations as well as the current value of each element:
val konfeatureInstance = konfeature {...}
val featureConfigSpec = konfeatureInstance.spec[0]
val featureSpec = featureConfigSpec.values[0]
val featureValue = konfeatureInstance.getValue(featureSpec)This can be useful for use in the DebugPanel
The value of the configuration element is determined in the following order:
defaultValue and Default source are assigned.sourceSelectionStrategy, a list of Sources from which a value can be requested is determined.Sources in the order they were added to Konfeature, stopping at the first occurrence of the element by key.
Upon successful search, the value from Source is assigned with Source(name=SourceName) source.Interceptors in the order they were added to Konfeature.
If Interceptor returns a value other than null, this value is assigned with Interceptor(name=InterceptorName) source.Merge requests are welcome.
For major changes, please open an issue first to discuss what you would like to change.
Konfeature is a powerful Kotlin Multiplatform library for managing remote configuration in your applications. It provides a clean, declarative API for working with feature flags and configuration elements across Android, iOS, and JVM platforms.
Working with remote configuration has become a standard part of the development process for almost any application. Depending on the complexity of the application, several requirements for such functionality may arise, including:
We have made every effort to meet all these requirements in the development of Konfeature.
Konfeature is a Kotlin Multiplatform library with support for:
| Platform | Status | Targets |
|---|---|---|
| Android | ✅ Fully Supported | JVM (via Kotlin/JVM) |
| iOS | ✅ Fully Supported | arm64, x86_64, simulator arm64 |
| JVM | ✅ Fully Supported | Java/Kotlin applications |
repositories {
mavenCentral()
}For Gradle (Kotlin Multiplatform Project):
kotlin {
sourceSets {
commonMain.dependencies {
implementation("com.redmadrobot.konfeature:konfeature:<version>")
}
}
}For Gradle (Single Platform):
dependencies {
implementation("com.redmadrobot.konfeature:konfeature:<version>")
}Defines a set of configuration elements, where each element is defined using a delegate. There are two types of delegates:
by toggle(...) - used for elements of type Boolean
by value(...) - used for elements of any other typeclass ProfileFeatureConfig : FeatureConfig(
name = "profile_feature_config",
description = "Config of features for profile usage"
) {
val isProfileFeatureEnabled: Boolean by toggle(
key = "profile_feature",
description = "show profile entry point for user",
defaultValue = false,
)
val profileFeatureTitle: String by value(
key = "profile_feature_title",
description = "title of profile entry point button",
defaultValue = "Feature number nine",
sourceSelectionStrategy = SourceSelectionStrategy.Any
)
val profileButtonAppearDuration: Long by value(
key = "profile_button_appear_duration",
description = "duration of profile button appearing in ms",
defaultValue = 200,
sourceSelectionStrategy = SourceSelectionStrategy.Any
)
}The configuration requires specifying:
name - the name of the configurationdescription - a detailed description of the configurationEach configuration element requires specifying:
key - used to retrieve the value of the element from a Source
description - a detailed description of the elementdefaultValue - used if the value cannot be found in a Source
sourceSelectionStrategy - the strategy for selecting a Source using SourceSelectionStrategy
After that, you need to register the configuration in Konfeature:
val profileFeatureConfig: FeatureConfig = ProfileFeatureConfig()
val konfeatureInstance = konfeature {
register(profileFeatureConfig)
}Similarly, you can add multiple configurations, for example, for each module, when organizing multi-modularity by features.
An abstraction over the value source for configuration elements.
public interface FeatureSource {
public val name: String
public fun get(key: String): Any?
}name - source nameget(key: String) - logic for getting values by key
Example implementation based on FirebaseRemoteConfig:
class FirebaseFeatureSource(
private val remoteConfig: FirebaseRemoteConfig
) : FeatureSource {
override val name: String = "FirebaseRemoteConfig"
override fun get(key: String): Any? {
return remoteConfig
.getValue(key)
.takeIf { source == FirebaseRemoteConfig.VALUE_SOURCE_REMOTE }
?.let { value: FirebaseRemoteConfigValue ->
value.getOrNull { asBoolean() }
?: value.getOrNull { asString() }
?: value.getOrNull { asLong() }
?: value.getOrNull { asDouble() }
}
}
private fun FirebaseRemoteConfigValue.getOrNull(
getter: FirebaseRemoteConfigValue.() -> Any?
): Any? {
return try {
getter()
} catch (error: IllegalArgumentException) {
null
}
}
}After that, you need to add the Source in Konfeature:
val profileFeatureConfig: FeatureConfig = ProfileFeatureConfig()
val source: FeatureSource = FirebaseFeatureSource(remoteConfig)
val konfeatureInstance = konfeature {
addSource(source)
register(profileFeatureConfig)
}Similarly, you can add multiple sources, for example, Huawei AppGallery, RuStore, or your own backend.
You can configure the retrieval of an element's value from the source more flexibly by using the sourceSelectionStrategy parameter:
val profileFeatureTitle: String by value(
key = "profile_feature_title",
description = "title of profile entry point button",
defaultValue = "Feature number nine",
sourceSelectionStrategy = SourceSelectionStrategy.Any
)Where sourceSelectionStrategy filters the available data sources.
public fun interface SourceSelectionStrategy {
public fun select(names: Set<String>): Set<String>
public companion object {
public val None: SourceSelectionStrategy = SourceSelectionStrategy { emptySet() }
public val Any: SourceSelectionStrategy = SourceSelectionStrategy { it }
public fun anyOf(vararg sources: String): SourceSelectionStrategy = SourceSelectionStrategy { sources.toSet() }
}
}The select(...) method receives a list of available Source names and returns a list of sources from which the configuration element can retrieve a value.
For most scenarios, predefined implementations will be sufficient:
SourceSelectionStrategy.None - prohibits taking values from any source, i.e., the value specified in defaultValue will always be usedSourceSelectionStrategy.Any - allows taking values from any sourceSourceSelectionStrategy.anyOf("Source 1", ... ,"Source N") - allows taking values from the specified list of sources[!IMPORTANT] By default,
SourceSelectionStrategy.Noneis used!
Allows intercepting and overriding the value of the element.
public interface Interceptor {
public val name: String
public fun intercept(valueSource: FeatureValueSource, key: String, value: Any): Any?
}name - the name of the interceptorintercept(valueSource: FeatureValueSource, key: String, value: Any): Any? - called when accessing the element with key and value from valueSource(Source(<name>), Interceptor(<name>), Default), and returns its new value or null if it doesn't changeExample of implementation based on DebugPanelInterceptor:
class DebugPanelInterceptor : Interceptor {
private val values = mutableMapOf<String, Any>()
override val name: String = "DebugPanelInterceptor"
override fun intercept(valueSource: FeatureValueSource, key: String, value: Any): Any? {
return values[key]
}
fun setFeatureValue(key: String, value: Any) {
values[key] = value
}
fun removeFeatureValue(key: String) {
values.remove(key)
}
}After that, you need to add the Interceptor in Konfeature:
val profileFeatureConfig: FeatureConfig = ProfileFeatureConfig()
val source: FeatureSource = FirebaseFeatureSource(remoteConfig)
val debugPanelInterceptor: Interceptor = DebugPanelInterceptor()
val konfeatureInstance = konfeature {
addSource(source)
register(profileFeatureConfig)
addInterceptor(debugPanelInterceptor)
}Similarly, you can add multiple interceptors.
public interface Logger {
public fun log(severity: Severity, message: String)
public enum class Severity {
WARNING, INFO
}
}The following events are logged:
Get value 'true' by key 'profile_feature' from 'Source(name=FirebaseRemoteConfig)'
Source or Interceptor returns an unexpected type for key
Unexpected value type for 'profile_button_appear_duration': expected type is 'kotlin.Long', but value from 'Source(name=FirebaseRemoteConfig)' is 'true' with type 'kotlin.Boolean'
Example of implementation based on Timber:
class TimberLogger: Logger {
override fun log(severity: Severity, message: String) {
if (severity == INFO) {
Timber.tag(TAG).i(message)
} else if (severity == WARNING) {
Timber.tag(TAG).w(message)
}
}
companion object {
private const val TAG = "Konfeature"
}
}After that, you need to add the Logger in Konfeature:
val profileFeatureConfig: FeatureConfig = ProfileFeatureConfig()
val source: FeatureSource = FirebaseFeatureSource(remoteConfig)
val debugPanelInterceptor: Interceptor = DebugPanelInterceptor()
val logger: Logger = TimberLogger()
val konfeatureInstance = konfeature {
addSource(source)
register(profileFeatureConfig)
addInterceptor(debugPanelInterceptor)
setLogger(logger)
}Konfeature contains information about all registered FeatureConfig in the form of spec:
public interface Konfeature {
public val spec: List<FeatureConfigSpec>
public fun <T : Any> getValue(spec: FeatureValueSpec<T>): FeatureValue<T>
}This allows you to obtain information about added configurations as well as the current value of each element:
val konfeatureInstance = konfeature {...}
val featureConfigSpec = konfeatureInstance.spec[0]
val featureSpec = featureConfigSpec.values[0]
val featureValue = konfeatureInstance.getValue(featureSpec)This can be useful for use in the DebugPanel
The value of the configuration element is determined in the following order:
defaultValue and Default source are assigned.sourceSelectionStrategy, a list of Sources from which a value can be requested is determined.Sources in the order they were added to Konfeature, stopping at the first occurrence of the element by key.
Upon successful search, the value from Source is assigned with Source(name=SourceName) source.Interceptors in the order they were added to Konfeature.
If Interceptor returns a value other than null, this value is assigned with Interceptor(name=InterceptorName) source.Merge requests are welcome.
For major changes, please open an issue first to discuss what you would like to change.