Class: Optimizely::DefaultCmabClient

Inherits:
Object
  • Object
show all
Defined in:
lib/optimizely/cmab/cmab_client.rb

Instance Method Summary collapse

Constructor Details

#initialize(http_client: nil, retry_config: nil, logger: nil, prediction_endpoint: nil) ⇒ DefaultCmabClient

Client for interacting with the CMAB service. Provides methods to fetch decisions with optional retry logic.



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# File 'lib/optimizely/cmab/cmab_client.rb', line 46

def initialize(http_client: nil, retry_config: nil, logger: nil, prediction_endpoint: nil)
  # Initialize the CMAB client.
  # Args:
  #   http_client: HTTP client for making requests.
  #   retry_config: Configuration for retry settings.
  #   logger: Logger for logging errors and info.
  #   prediction_endpoint: Custom prediction endpoint URL template.
  #                        Use #{rule_id} as placeholder for rule_id.
  @http_client = http_client || DefaultHttpClient.new
  @retry_config = retry_config || CmabRetryConfig.new
  @logger = logger || NoOpLogger.new
  @prediction_endpoint = if prediction_endpoint.to_s.strip.empty?
                           'https://prediction.cmab.optimizely.com/predict/%s'
                         else
                           prediction_endpoint
                         end
end

Instance Method Details

#_do_fetch(url, request_body, timeout) ⇒ Object 



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# File 'lib/optimizely/cmab/cmab_client.rb', line 93

def _do_fetch(url, request_body, timeout)
  # Perform a single fetch request to the CMAB prediction service.

  # Args:
  #   url: The endpoint URL.
  #   request_body: The request payload.
  #   timeout: Maximum wait time for the request to respond in seconds.
  # Returns:
  #   The variation ID from the response.

  headers = {'Content-Type' => 'application/json'}
  begin
    response = @http_client.post(url, json: request_body, headers: headers, timeout: timeout.to_i)
  rescue StandardError => e
    error_message = Optimizely::Helpers::Constants::CMAB_FETCH_FAILED % e.message
    @logger.log(Logger::ERROR, error_message)
    raise CmabFetchError, error_message
  end

  unless (200..299).include?(response.status_code)
    error_message = Optimizely::Helpers::Constants::CMAB_FETCH_FAILED % response.status_code
    @logger.log(Logger::ERROR, error_message)
    raise CmabFetchError, error_message
  end

  begin
    body = response.json
  rescue JSON::ParserError, Optimizely::CmabInvalidResponseError
    error_message = Optimizely::Helpers::Constants::INVALID_CMAB_FETCH_RESPONSE
    @logger.log(Logger::ERROR, error_message)
    raise CmabInvalidResponseError, error_message
  end

  unless validate_response(body)
    error_message = Optimizely::Helpers::Constants::INVALID_CMAB_FETCH_RESPONSE
    @logger.log(Logger::ERROR, error_message)
    raise CmabInvalidResponseError, error_message
  end

  body['predictions'][0]['variation_id']
end

#_do_fetch_with_retry(url, request_body, retry_config, timeout) ⇒ Object 



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# File 'lib/optimizely/cmab/cmab_client.rb', line 150

def _do_fetch_with_retry(url, request_body, retry_config, timeout)
  # Perform a fetch request with retry logic.
  # Args:
  #   url: The endpoint URL.
  #   request_body: The request payload.
  #   retry_config: Configuration for retry settings.
  #   timeout: Maximum wait time for the request to respond in seconds.
  # Returns:
  #   The variation ID from the response.

  backoff = retry_config.initial_backoff

  (0..retry_config.max_retries).each do |attempt|
    variation_id = _do_fetch(url, request_body, timeout)
    return variation_id
  rescue StandardError => e
    if attempt < retry_config.max_retries
      @logger.log(Logger::INFO, "Retrying CMAB request (attempt #{attempt + 1}) after #{backoff} seconds...")
      Kernel.sleep(backoff)

      backoff = [
        backoff * retry_config.backoff_multiplier,
        retry_config.max_backoff
      ].min
    else
      @logger.log(Logger::ERROR, "Max retries exceeded for CMAB request: #{e.message}")
      raise Optimizely::CmabFetchError, "CMAB decision fetch failed (#{e.message})."
    end
  end
end

#fetch_decision(rule_id, user_id, attributes, cmab_uuid, timeout: MAX_WAIT_TIME) ⇒ Object 



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# File 'lib/optimizely/cmab/cmab_client.rb', line 64

def fetch_decision(rule_id, user_id, attributes, cmab_uuid, timeout: MAX_WAIT_TIME)
  # Fetches a decision from the CMAB service.
  # Args:
  #   rule_id: The rule ID for the experiment.
  #   user_id: The user ID for the request.
  #   attributes: User attributes for the request.
  #   cmab_uuid: Unique identifier for the CMAB request.
  #   timeout: Maximum wait time for the request to respond in seconds. (default is 10 seconds).
  # Returns:
  #   The variation ID.
  url = format(@prediction_endpoint, rule_id)
  cmab_attributes = attributes.map { |key, value| {'id' => key.to_s, 'value' => value, 'type' => 'custom_attribute'} }

  request_body = {
    instances: [{
      visitorId: user_id,
      experimentId: rule_id,
      attributes: cmab_attributes,
      cmabUUID: cmab_uuid
    }]
  }

  if @retry_config && @retry_config.max_retries.to_i.positive?
    _do_fetch_with_retry(url, request_body, @retry_config, timeout)
  else
    _do_fetch(url, request_body, timeout)
  end
end

#validate_response(body) ⇒ Object 



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# File 'lib/optimizely/cmab/cmab_client.rb', line 135

def validate_response(body)
  # Validate the response structure from the CMAB service.
  # Args:
  #   body: The JSON response body to validate.
  # Returns:
  #   true if valid, false otherwise.

  body.is_a?(Hash) &&
    body.key?('predictions') &&
    body['predictions'].is_a?(Array) &&
    !body['predictions'].empty? &&
    body['predictions'][0].is_a?(Hash) &&
    body['predictions'][0].key?('variation_id')
end