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Configure the Logger

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Every backend application relies on some kind of logs to debug it. The VWO SDK logger logs information about your running campaigns to help you with debugging. You can customize what kind of logs you need and where to send these, that is, you can write your own logger implementation to write the logs on some file, database, or some third-party logging service.

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Note

For the production environment, we recommend that you pass in your custom logger implementation while creating a VWO client instance.

Log Levels

Log LevelDescription
ERROR The events that prevent campaigns from functioning properly (for example, invalid settingsFile while initializing the VWO SDK, invalid campaign keys, or goal identifiers) are logged.
WARNING The events that don't prevent campaigns from functioning correctly, but can have unexpected outcomes (for example, future API deprecation) are logged.
INFO The events which are useful and provide a certain level of information (for example, activate started, bucket value assigned, part of a campaign, tracking user, conversion succeeded, and others) are logged. This depicts the flow of the API method used.
DEBUG Any kind of useful information that can help VWO debug the issue in case of unexpected behavior (for example, a user is not in a campaign, bucket value assigned, hash value assigned, and stored User Storage Service used, and others) are logged.

To filter these log levels while writing your own logger implementation, use the Enum provided to you by VWO SDKs.

@@logger_instance = logger_instance || Logger.new(STDOUT, level: :debug)
@@logger_instance = logger_instance || Logger.new(STDOUT, level: :info)
@@logger_instance = logger_instance || Logger.new(STDOUT, level: :warning)
@@logger_instance = logger_instance || Logger.new(STDOUT, level: :error)

See the code example below on how to use these appropriately.

Example

# Basic Custom Logging Before Starting App
class VWO
  class CustomLogger
    def initialize(logger_instance)
      # Only log info logs and above, no debug
      @@logger_instance = logger_instance || Logger.new(STDOUT, level: :info)
    end

    def log(level, message)
      # Basic Modification
      message = "#{Time.now} #{message}"
      @@logger_instance.log(level, message)
    end
  end
end


# Custom Logging After Starting App
def start_custom_logger
  VWO::CustomLogger.class_eval do
    # Override this method to handle logs in a custom manner
    def log(level, message)
      # Modify message for custom logging
      message = "Custom message #{message}"
      VWO::CustomLogger.class_variable_get('@@logger_instance').log(level, message)
    end
  end
end

def stop_custom_logger
  VWO::CustomLogger.class_eval do
    def log(level, message)
      message = "#{Time.now} #{message}"
      VWO::CustomLogger.class_variable_get('@@logger_instance').log(level, message)
    end
  end
end

start_custom_logger
# Call API methods
stop_custom_logger

Updated over 3 years ago