go-server-optimizely-feature-flags

Dabbling with go and optimizely, created a simple server to return enabled features for users.

Please read optimizely documentation. https://docs.developers.optimizely.com/full-stack/docs

The Api /api/feature-flags takes one optional arugment which is user_idand it returns the list of features that are enabled for that user. If you don't specify a user_id, it will autogenerate one and send it back in the header.

Example response header.

Feature-Flag: Feature-1;Feature-2
UUID: 123231-2122112-12212121 (UUID v4)

If you set the following cookie __test_user to "true" It will pass it as an attribute to getEnabledFeatures attribute.

Here is the main function that does the heavy lifting, this snippet is taken from this module within the repo pkg/featureflags/featureflags.go

func (optiService *OptiService) GetEnabledFeatures(w http.ResponseWriter, r *http.Request) {
	log.Println("Endpoint Hit: api/feature-flags")
	
	attributes := map[string]interface{}{
		"test_audience": isTestUser(r),
	}

	userID := getOrGenerateUID(r)
	w.Header().Add("UUID", userID)

	user := entities.UserContext{
		ID:         userID,
		Attributes: attributes,
	}
	enabledFeatures, err := optiService.Client.GetEnabledFeatures(user)
	
	checkError(err)

	w.Header().Add("Feature-Flags", string(strings.Join(enabledFeatures, ";")))
	fmt.Fprintf(w, "Feature-Flags: \nThose are the enabled features: %s", enabledFeatures)
}

TO Run.

1. Install docker.
2. cp .env.template .env and get optimizely SDK key.
3. execute docker-compose up. The server should be running on localhost:10000

TODO:

1. write tests