At runtime, GraphQL-Ruby will output debug information using GraphQL::Query.logger. By default, this uses Rails.logger. To see output, make sure config.log_level = :debug is set. (This information isn’t meant for production logs.)

You can configure a custom logger with GraphQL::Schema.default_logger, for example:

class MySchema < GraphQL::Schema
  # This logger will be used by queries during execution:
  default_logger MyCustomLogger.new

You can also pass context[:logger] to provide a logger during execution.