Merge branch 'dbarrett/deprecated_fields' into 'master'

  # Fields is intended to be a SSOT for all of the common field names that

  # we emit via any observability we add to our systems.

  #

  # These fields should span multiple services. This is

  # These fields should span multiple services.

  #

  # The goal of this package is to reduce the likelihood for typos or

  # subtly different naming conventions. This will help to ensure we

  module Fields

    # correlation_id - string

    #

    # correlation_id - string

    # This field is used to correlate

    # the logs emitted by all of our systems.

    # This should be present in all log line

    # should clearly indicate what the intended use of the

    # field is and should be replicated across the labkit

    # variations.

    # Get the constant name for a field value

    # @param field_value [String] The field value (e.g., "gl_user_id")

    # @return [String, nil] The constant name (e.g., "GL_USER_ID") or nil if not found

    def self.constant_name_for(field_value)

      constants(false).find do |const_name|

        next if const_name == :Deprecated

        const_get(const_name) == field_value

      end&.to_s

    end

    module Deprecated

      # This module tracks deprecated field names and maps them to their

      # standard replacements. These mappings are used by the field scanner

      # to identify and track usage of deprecated fields in the codebase.

      MAPPINGS = {

        Fields::GL_USER_ID => %w[user_id userid],

      }.freeze

      class << self

        # Get all deprecated fields as a lookup hash

        #

        # @return [Hash{String => String}] Hash mapping deprecated field names to standard field names

        def all

          @all ||= MAPPINGS.each_with_object({}) do |(key, values), result|

            values.each { |v| result[v] = key }

          end

        end

        # Check if a field is deprecated

        #

        # @param field_name [String, Symbol] The field name to check

        # @return [Boolean] true if the field is deprecated

        def deprecated?(field_name)

          all.key?(field_name.to_s)

        end

        # Get the standard field for a deprecated field

        #

        # @param deprecated_field [String, Symbol] The deprecated field name

        # @return [String, nil] The standard field name, or nil if not found

        def standard_field_for(deprecated_field)

          all[deprecated_field.to_s]

        end

      end

    end

  end

end

# frozen_string_literal: true

require 'spec_helper'

RSpec.describe Labkit::Fields do

  describe Labkit::Fields::Deprecated do

    describe '.all' do

      it 'returns a hash mapping deprecated field names to standard field names' do

        expect(described_class.all).to be_a(Hash)

        expect(described_class.all.keys).to all(be_a(String))

        expect(described_class.all.values).to all(be_a(String))

      end

      it 'maps deprecated fields to their standard equivalents' do

        expect(described_class.all['user_id']).to eq(Labkit::Fields::GL_USER_ID)

      end

    end

    describe '.deprecated?' do

      it 'returns true for a known deprecated field' do

        result = described_class.deprecated?('user_id')

        expect(result).to be(true)

      end

      it 'returns false for a known standard field' do

        result = described_class.deprecated?(Labkit::Fields::GL_USER_NAME)

        expect(result).to be(false)

      end

    end

    describe '.standard_field_for' do

      it 'returns a standard field for a known deprecated field' do

        result = described_class.standard_field_for('user_id')

        expect(result).to be(Labkit::Fields::GL_USER_ID)

      end

    end

    describe 'MAPPINGS' do

      it 'has no duplicate deprecated field names' do

        all_deprecated = described_class::MAPPINGS.values.flatten

        expect(all_deprecated).to eq(all_deprecated.uniq)

      end

    end

  end

end