Client for feature toggle server

The feature toggle client has two methods

• sendVariables(userId: String, variables: Map<String, Any>): Unit
• isEnabled(featureToggleId: String, userId: String, defaultValue: Boolean): Boolean

And it needs a configuration owl.toggle.client.server-url with the url of the feature toggle server.

The sendVariables method

It's used to feed the server with variables that can be used to evaluate the rules. A common cenario of use it's to call this method on every user login. The first parameter is the user id and the second one store the variables, it's is of type Map<String, Any>. Example of use:

@RestController
class LoginController {

    private val loginService: LoginService
    private val featureToggleClient: FeatureToggleClient

    @Autowired
    constructor(loginService: LoginService, featureToggleClient: FeatureToggleClient) {
        this.loginService = loginService
        this.featureToggleClient = featureToggleClient
    }

    @PostMapping("/login")
    fun login(@RequestBody login: Login, @RequestHeader("client-version") version: Int): AccessToken {

        val loginResponse = loginService.login(login.username, login.password)

        if(loginResponse.success) {
            featureToggleClient.sendVariables(login.username, mapOf("appVersion" to version))
            return loginResponse.accessToken
        }

        throw InvalidCredentialsExcpetion()

    }

}

The isEnabled method

It's were the magic happens! It's the method used to check if a feature toggle is enabled or disabled. It has 3 parameters, the first one is the feature toggle identification, the second is the user id and the third one is an optional parameter with a default value to return if the feature toggle doesn't exist. Example of use:

@Service
class TimelineService {

  private val featureToggleClient: FeatureToggleClient
  private const val FEATURE_TOGGLE_ID = "my_toggle"

  @Autowired
  constructor(featureToggleClient: FeatureToggleClient) {
      this.featureToggleClient = featureToggleClient
  }


  fun doSomeWork(userId: String) {

      if(featureToggleClient.isEnabled(FEATURE_TOGGLE_ID, userId, false)) {
          doWorkThisWay()
      } else {
          doWorkThatWay()
      }
  }

  [...]
}