Launch Darkly

Tested with Launch Darkly version 9.12.0 (iOS)

Third party remote configuration provider integration is currently in private beta and will be available in the next major release of Appfigurate.

Using Appfigurate remote properties instead of Launch Darkly flag evaluation APIs directly allows for the following:

• locally change Launch Darkly flags without affecting your entire customer base.

• compile time type safety - Appfigurate remote properties are typed, Launch Darkly flags are not.

• avoids hardcoding duplicated flag names throughout your app.

• avoids hardcoding duplicated default values throughout your app.

• deleting a flag from Launch Darkly Console won't affect existing apps, they'll continue to use the default value provided in the reset method.

We assume you already have Appfigurate Library and Launch Darkly integrated into your app with the following example remote properties created in the Launch Darkly console:

Add remote properties into your Configuration subclass

Update your configuration subclass to include your remote configuration properties. Provide default values for the properties in the overridden reset method. See also Supported property types.

Swift

Swift Configuration example

import Foundation
import AppfigurateLibrary

@objcMembers class MyConfiguration: APLConfiguration {
...
    @RemoteBoolProperty(remoteKey: "alwaysDarkMode", description: "Force dark mode to be always set")
    var alwaysDarkMode: Bool

    @RemoteStringPropertyEdit(remoteKey: "appTitle", description: "Title of application")
    var appTitle: String

    @RemoteIntPropertyEdit(remoteKey: "bookingDuration", description: "Duration (days) for reservation bookings")
    var bookingDuration: Int

    @RemoteDoublePropertyEdit(remoteKey: "fontSize", description: "Size of font throughout app")
    var fontSize: Double
...
    override func reset() {
        alwaysDarkMode = false
        appTitle = "Holiday finder"
        bookingDuration = 30
        fontSize = 13.0
    }
...
}

Objective-C

Objective-C Configuration header example

@import Foundation;
@import AppfigurateLibrary;

@interface MyConfiguration : APLConfiguration
...
@property(nonatomic, assign) BOOL alwaysDarkMode;
@property(nonatomic, strong) NSString* appTitle;
@property(nonatomic, assign) NSInteger bookingDuration;
@property(nonatomic, assign) double fontSize;
...
@end

Objective-C Configuration implementation example

#import "MyConfiguration.h"

@implementation MyConfiguration
...
REMOTE_BOOL_PROPERTY(alwaysDarkMode, @"alwaysDarkMode", @"Force dark mode to be always set");
REMOTE_STRING_PROPERTY_EDIT(appTitle, @"appTitle", @"Title of application");
REMOTE_INT_PROPERTY_EDIT(bookingDuration, @"bookingDuration", @"Duration (days) for reservation bookings");
REMOTE_DOUBLE_PROPERTY_EDIT(fontSize, @"fontSize", @"Size of font throughout app");
...
- (void) reset {
    self.alwaysDarkMode = NO;
    self.appTitle = @"Holiday finder";
    self.bookingDuration = 30;
    self.fontSize = 13.0;
}
...
@end

Kotlin

Kotlin Configuration example

package com.yourcompany.yourapp

import nz.co.electricbolt.appfiguratelibrary.annotations.RemoteBooleanProperty
import nz.co.electricbolt.appfiguratelibrary.annotations.RemoteDoublePropertyEdit
import nz.co.electricbolt.appfiguratelibrary.annotations.RemoteIntPropertyEdit
import nz.co.electricbolt.appfiguratelibrary.annotations.RemoteStringPropertyEdit

class MyConfiguration : nz.co.electricbolt.appfiguratelibrary.Configuration() {
...
    @RemoteBooleanProperty(remoteKey = "alwaysDarkMode", description = "Force dark mode to be always set")
    var alwaysDarkMode: Boolean = false

    @RemoteStringPropertyEdit(remoteKey = "appTitle", description = "Title of application")
    var appTitle: String? = null

    @RemoteDoublePropertyEdit(remoteKey = "fontSize", description = "Size of font throughout app")
    var fontSize: Double = 0.0

    @RemoteIntPropertyEdit(remoteKey = "bookingDuration", description = "Duration (days) for reservation bookings")
    var bookingDuration: Int = 0
...
    override fun reset() {
        alwaysDarkMode = false
        appTitle = "Holiday finder"
        bookingDuration = 30  
        fontSize = 13.0
    }
}

Java

Java Configuration example

package com.yourcompany.yourapp;

import nz.co.electricbolt.appfiguratelibrary.annotations.RemoteBooleanProperty;
import nz.co.electricbolt.appfiguratelibrary.annotations.RemoteDoublePropertyEdit;
import nz.co.electricbolt.appfiguratelibrary.annotations.RemoteIntPropertyEdit;
import nz.co.electricbolt.appfiguratelibrary.annotations.RemoteStringPropertyEdit;

public class MyConfiguration extends nz.co.electricbolt.appfiguratelibrary.Configuration {
...
    @RemoteBooleanProperty(remoteKey = "alwaysDarkMode", description = "Force dark mode to be always set")
    public boolean alwaysDarkMode;

    @RemoteStringPropertyEdit(remoteKey = "appTitle", description = "Title of application")
    public String appTitle;

    @RemoteDoublePropertyEdit(remoteKey = "fontSize", description = "Size of font throughout app")
    public double fontSize;

    @RemoteIntPropertyEdit(remoteKey = "bookingDuration", description = "Duration (days) for reservation bookings")
    public int bookingDuration;
...
    @Override
    public void reset() {
        alwaysDarkMode = false;
        appTitle = "Holiday finder";
        bookingDuration = 30;        
        fontSize = 13.0;
    }
...
}

Provide remote configuration values to Appfigurate Library when requested

Appfigurate Library needs to be able to read the current remote flags from Launch Darkly. Copy and paste the following code into your app.

Swift

Swift example

APLFetchRemoteConfiguration { propertyKey, propertyType, defaultValue in
    if propertyType == .bool {
        return NSNumber(value: (LDClient.get()!.boolVariation(forKey: propertyKey, defaultValue: (defaultValue as! NSNumber).boolValue)))
    } else if propertyType == .int {
        return NSNumber(value: (LDClient.get()!.intVariation(forKey: propertyKey, defaultValue: (defaultValue as! NSNumber).intValue)))
    } else if propertyType == .double {
        return NSNumber(value: (LDClient.get()!.doubleVariation(forKey: propertyKey, defaultValue: (defaultValue as! NSNumber).doubleValue)))
    } else { // .string 
        return NSString(string: LDClient.get()!.stringVariation(forKey: propertyKey, defaultValue: (defaultValue as! String)))
    }
}

Objective-C

Objective-C example

APLFetchRemoteConfiguration(^NSObject* (NSString* propertyKey, APLRemotePropertyType propertyType, NSObject* defaultValue) {
    if (propertyType == APLRemotePropertyTypeBool) {
        return [NSNumber numberWithBool: [[LDClient get] boolVariationForKey: propertyKey defaultValue: [((NSNumber*) defaultValue) boolValue]]];
    } else if (propertyType == APLRemotePropertyTypeInt) {
        return [NSNumber numberWithInteger: [[LDClient get] integerVariationForKey: propertyKey defaultValue: [((NSNumber*) defaultValue) integerValue]]];
    } else if (propertyType == APLRemotePropertyTypeDouble) {
        return [NSNumber numberWithDouble: [[LDClient get] doubleVariationForKey: propertyKey defaultValue: [((NSNumber*) defaultValue) doubleValue]]];
    } else { // APLRemotePropertyTypeString 
        return [[LDClient get] stringVariationForKey: propertyKey defaultValue: (NSString*) defaultValue];
    }
});

Kotlin

Kotlin example

Appfigurate.fetchRemoteConfiguration { propertyKey: String, propertyType: RemotePropertyType, defaultValue: Any? ->
    try {
        if (propertyType == RemotePropertyTypeString)
            LDClient.get().stringVariation(propertyKey, defaultValue as String)
        else if (propertyType == RemotePropertyTypeBoolean)
            LDClient.get().boolVariation(propertyKey, defaultValue as Boolean)
        else if (propertyType == RemotePropertyTypeInt)
            LDClient.get().intVariation(propertyKey, defaultValue as Int)
        else // RemotePropertyTypeDouble
            LDClient.get().doubleVariation(propertyKey, defaultValue as Double)
    } catch (e: LaunchDarklyException) {
        defaultValue
    }
}

Java

Java example

Appfigurate.fetchRemoteConfiguration((propertyKey, propertyType, defaultValue) -> {
    try {
        return switch (propertyType) {
            case RemotePropertyTypeString -> LDClient.get().stringVariation(propertyKey, (String) defaultValue);
            case RemotePropertyTypeBoolean -> LDClient.get().boolVariation(propertyKey, (Boolean) defaultValue);
            case RemotePropertyTypeInt -> LDClient.get().intVariation(propertyKey, (Integer) defaultValue);
            case RemotePropertyTypeDouble -> LDClient.get().doubleVariation(propertyKey, (Double) defaultValue);
        };
    } catch(LaunchDarklyException e) {
        return defaultValue;
    }
});

Notify Appfigurate Library when Launch Darkly has received flags

We need to tell Appfigurate Library that Launch Darkly has received flags, so that it can keep your Configuration subclasses remote properties in sync.

Swift

Add a call to APLFlushRemoteConfiguration in any existing Launch Darkly start(config, startWaitSeconds, completion) and observeAll(owner, handler) blocks.

Swift example

LDClient.start(config: config, startWaitSeconds: 5.0) { timedOut in
    ...
    APLFlushRemoteConfiguration() // add this line
}
...
LDClient.get()?.observeAll(owner: self) { keys in
    ...
    APLFlushRemoteConfiguration() // add this line
}

Objective-C

Add a call to APLFlushRemoteConfiguration in any existing Launch Darkly startWithConfiguration:startWaitSeconds:completion: and observeAllKeysWithOwner:handler: blocks.

Objective-C example

[LDClient startWithConfiguration:config startWaitSeconds:5.0 completion:^(bool timedOut) {
    ...
    APLFlushRemoteConfiguration(); // add this line
}];
...
[[LDClient get] observeAllKeysWithOwner: self handler:^(NSDictionary<NSString *,LDChangedFlag *> *handler) {
    ...
    APLFlushRemoteConfiguration(); // add this line
}];

Kotlin

The Android Launch Darkly SDK doesn't have functionality that notifies you of flags being received during the LDClient.init call. Instead we must programmatically check for a well known flag's evaluation detail, and then call Appfigurate.flushRemoteConfiguration as appropriate.

Add another call to Appfigurate.flushRemoteConfiguration in a Launch Darkly registerAllFlagsListener block.

Java example

LDClient.init(...)
...
// add this block of code
if (LDClient.get().boolVariationDetail("alwaysDarkMode", false).variationIndex > EvaluationDetail.NO_VARIATION) {
    // Flags loaded by LDClient.init()
    Appfigurate.flushRemoteConfiguration()
}
...
LDClient.get().registerAllFlagsListener {
    ...
    Appfigurate.flushRemoteConfiguration() // add this line
}

Java

The Android Launch Darkly SDK doesn't have functionality that notifies you of flags being received during the LDClient.init call. Instead we must programmatically check for a well known flag's evaluation detail, and then call Appfigurate.flushRemoteConfiguration as appropriate.

Add another call to Appfigurate.flushRemoteConfiguration in a Launch Darkly registerAllFlagsListener block.

Java example

LDClient.init(...)
...
// add this block of code
if (LDClient.get().boolVariationDetail("alwaysDarkMode", false).variationIndex > EvaluationDetail.NO_VARIATION) {
    // Flags loaded by LDClient.init()
    Appfigurate.flushRemoteConfiguration();
}
...
LDClient.get().registerAllFlagsListener(new LDAllFlagsListener() {
    @Override
    public void onChange(List<String> flagKey) {
        ...
        Appfigurate.flushRemoteConfiguration(); // add this line
    }
});

Best practice and usage

Swift

Replace all calls to Launch Darkly boolVariation(forKey:defaultValue:), intVariation(forKey:defaultValue:), doubleVariation(forKey:defaultValue), stringVariation(forKey:defaultValue:)

if (LDClient.get()!.boolVariation(forKey: "alwaysDarkMode", defaultValue: false)) {
    ...

with the following:

if ((APLConfiguration.shared() as! MyConfiguration).alwaysDarkMode) {
    ...

Objective-C

Replace all calls to Launch Darkly boolVariationForKey:defaultValue:, intVariationForKey:defaultValue:, doubleVariationForKey:defaultValue, stringVariationForKey:defaultValue:

if ([[LDClient get] boolVariationForKey: @"alwaysDarkMode" defaultValue: NO]) {
    ...

with the following:

if (((MyConfiguration*) [APLConfiguration sharedConfiguration]).alwaysDarkMode) {
    ...

Kotlin

Replace all calls to Launch Darkly boolVariation(), intVariation(), doubleVariation(), stringVariation()

try {
   if (LDClient.get().boolVariation("alwaysDarkMode", false)) {
      ...
   }
} catch(e: LaunchDarklyException) {
   ...
}

with the following:

if (((MyConfiguration) Configuration.sharedConfiguration()).alwaysDarkMode) {
   ...

Java

Replace all calls to Launch Darkly boolVariation(), intVariation(), doubleVariation(), stringVariation()

try {
   if (LDClient.get().boolVariation("alwaysDarkMode", false)) {
      ...
   }
} catch(LaunchDarklyException e) {
   ...
}

with the following:

if (((MyConfiguration) Configuration.sharedConfiguration()).alwaysDarkMode) {
   ...