Feature Flag in iOS
Installation
Add the package using Swift Package Manager
Package link: AWS SDK for Swift
Select App Config
Fetch temporary access key, secret key, and session token from Cognito
private static func getTemporaryAWSCredentials(region: String, idToken: String) async throws -> CognitoIdentityClientTypes.Credentials {
let identityConfig = try await CognitoIdentityClient.CognitoIdentityClientConfiguration(
region: region
)
let identityClient = CognitoIdentityClient(config: identityConfig)
let identityIdInput = GetIdInput(
identityPoolId: Secrets.cognitoIdentityPoolId,
logins: ["cognito-idp.\(region).amazonaws.com/\(Secrets.cognitoUserPoolId)": idToken]
)
let identityIdResponse = try await identityClient.getId(input: identityIdInput)
guard let identityId = identityIdResponse.identityId else {
throw NSError(
domain: "FeatureFlagManager",
code: 3,
userInfo: [NSLocalizedDescriptionKey: "Failed to retrieve identity ID."]
)
}
let credentialsInput = GetCredentialsForIdentityInput(
identityId: identityId,
logins: identityIdInput.logins
)
let credentialsResponse = try await identityClient.getCredentialsForIdentity(input: credentialsInput)
guard let credentials = credentialsResponse.credentials else {
throw NSError(
domain: "FeatureFlagManager",
code: 2,
userInfo: [NSLocalizedDescriptionKey: "Failed to retrieve temporary AWS credentials."]
)
}
return credentials
}
Configure AppConfig
let credentials = try await FeatureFlagManager.getTemporaryAWSCredentials(region: region, idToken: idToken)
// Create static credentials provider
let credentialsProvider = AWSCredentialIdentity(
accessKey: credentials.accessKeyId ?? "",
secret: credentials.secretKey ?? "",
sessionToken: credentials.sessionToken
)
debugLog(credentials)
// Configure the AWS
let identity = try StaticAWSCredentialIdentityResolver(credentialsProvider)
let config = try await AppConfigDataClient.AppConfigDataClientConfiguration(awsCredentialIdentityResolver: identity, region: region)
self.client = try await AppConfigDataClient(config: config)
self.appConfigId = appConfigId
self.environment = environment
Start a configuration session and fetch latest configuration
func getConfiguration() async throws -> String {
let sessionInput = StartConfigurationSessionInput(
applicationIdentifier: appConfigId,
configurationProfileIdentifier: Secrets.configurationID,
environmentIdentifier: environment
)
let sessionResponse = try await client.startConfigurationSession(input: sessionInput)
token = sessionResponse.initialConfigurationToken ?? ""
// Fetch latest configuration
let getConfigInput = GetLatestConfigurationInput(configurationToken: token)
let configResponse = try await client.getLatestConfiguration(input: getConfigInput)
// Extract configuration data
guard let content = configResponse.configuration,
let jsonString = String(data: content, encoding: .utf8) else {
throw NSError(
domain: "FeatureFlagManager",
code: 1,
userInfo: [NSLocalizedDescriptionKey: "Failed to decode configuration content."]
)
}
return jsonString
}
Example response
{"release-1":{"enabled":true},"release-2":{"enabled":false}}