class Fluent::Plugin::GrepFilter

def filter(tag, time, record)
  begin
    if @_regexp_and_conditions && @_regexp_and_conditions.any? { |expression| !expression.match?(record) }
      return nil
    end
    if @_regexp_or_conditions && @_regexp_or_conditions.none? { |expression| expression.match?(record) }
      return nil
    end
    if @_exclude_and_conditions && @_exclude_and_conditions.all? { |expression| expression.match?(record) }
      return nil
    end
    if @_exclude_or_conditions && @_exclude_or_conditions.any? { |expression| expression.match?(record) }
      return nil
    end
  rescue => e
    log.warn "failed to grep events", error: e
    log.warn_backtrace
  end
  record
end