Experiment Ruby SDK

initialize_remote(apiKey, config = nil) : Client

fetch_v2(user: AmplitudeExperiment::User, fetch_options: AmplitudeExperiment::FetchOptions = nil) : Variants

user = AmplitudeExperiment::User.new(
    user_id: 'user@company.com',
    device_id: 'abcdefg',
    user_properties: {
        'premium' => true
    }
)
variants = experiment.fetch_v2(user)

variant = variants['YOUR-FLAG-KEY']
unless variant.nil?
  if variant.value == 'on'
    # Flag is on
  else
    # Flag is off
  end
end

fetch_async_v2(user: AmplitudeExperiment::User, fetch_options: AmplitudeExperiment::FetchOptions = nil, &callback)

experiment.fetch_async_v2(user) do |_, variants|
  variant = variants['sdk-ci-test']
  unless variant.nil?
    if variant.value == 'on'
      # Flag is on
    else
      # Flag is off
    end
  end
end

AmplitudeExperiment.initialize_local(api_key)

start

experiment.start

evaluate_v2(user: AmplitudeExperiment::User, flag_keys: Array[String] = [], options: AmplitudeExperiment::EvaluateOptions = nil) : Hash[String, Variant]

# The user to evaluate
user = AmplitudeExperiment::User.new(user_id: 'test-user')
# Evaluate all flag variants
all_variants = experiment.evaluate_v2(user)
# Evaluate a specific subset of flag variants
specific_variants = experiment.evaluate_v2(user, ["<FLAG_KEY_1>", "<FLAG_KEY_2>"])
# Access a variant
variant = all_variants["<FLAG_KEY>"]
if variant.value == 'on':
    # Flag is on
else:
    # Flag is off
end

experiment = AmplitudeExperiment.initialize_local('DEPLOYMENT_KEY',
  # (Recommended) Enable local evaluation cohort targeting.
  AmplitudeExperiment::LocalEvaluationConfig.new(
    cohort_sync_config: AmplitudeExperiment::CohortSyncConfig.new(
      api_key: 'API_KEY',
      secret_key: 'SECRET_KEY'
    )
  )
)

require 'logger'
require 'amplitude-experiment'
# Create a custom logger
custom_logger = Logger.new('experiment.log')
custom_logger.level = Logger::WARN
custom_logger.formatter = proc do |severity, datetime, progname, msg|
  "#{datetime}: #{severity} - #{msg}\n"
end
# Remote evaluation with custom logger
remote_config = AmplitudeExperiment::RemoteEvaluationConfig.new(
  logger: custom_logger
)
experiment = AmplitudeExperiment.initialize_remote('DEPLOYMENT_KEY', remote_config)
# Provide Local evaluation with your Rails logger
local_config = AmplitudeExperiment::LocalEvaluationConfig.new(
  logger: Rails.logger
)
experiment = AmplitudeExperiment.initialize_local('DEPLOYMENT_KEY', local_config)

# Without custom logger, debug=false uses ERROR level
config = AmplitudeExperiment::RemoteEvaluationConfig.new(
  debug: false
)
# Default logger level is ERROR
# Without custom logger, debug=true uses DEBUG level
config = AmplitudeExperiment::RemoteEvaluationConfig.new(
  debug: true
)
# Default logger level is DEBUG

custom_logger = Logger.new($stdout)
custom_logger.level = Logger::WARN
# Custom logger maintains its WARN level regardless of debug flag
config = AmplitudeExperiment::RemoteEvaluationConfig.new(
  logger: custom_logger,
  debug: true
)
# Logger level stays WARN (debug flag is ignored)

require 'amplitude-experiment'
require 'securerandom'
# Get the cookie name for the Amplitude API key
# Use new_format: true for Browser SDK 2.0 cookies
amp_cookie_name = AmplitudeExperiment::AmplitudeCookie.cookie_name('amplitude-api-key')
# For Browser SDK 2.0: AmplitudeExperiment::AmplitudeCookie.cookie_name('amplitude-api-key', new_format: true)
device_id = nil
# Try to get device ID from existing cookie
unless cookies[amp_cookie_name].nil?
  device_id = AmplitudeExperiment::AmplitudeCookie.parse(cookies[amp_cookie_name]).device_id
  # For Browser SDK 2.0: AmplitudeExperiment::AmplitudeCookie.parse(cookies[amp_cookie_name], new_format: true).device_id
end
# If no device ID found, generate a new one and set the cookie
if device_id.nil?
  device_id = SecureRandom.uuid
  amp_cookie_value = AmplitudeExperiment::AmplitudeCookie.generate(device_id)
  # For Browser SDK 2.0: AmplitudeExperiment::AmplitudeCookie.generate(device_id, new_format: true)
  cookies[amp_cookie_name] = {
    value: amp_cookie_value,
    domain: '.your-domain.com', # this should be the same domain used by the Amplitude JS SDK
    httponly: false,
    secure: false
  }
end