mongodb/bson-ruby

#!/usr/bin/env ruby
# frozen_string_literal: true

require 'erb'
require 'yaml'

# A utility for building an evergreen config file.
module ConfigProcessor
  extend self

  GENERATED_BANNER = <<~BANNER
    # GENERATED FILE - DO NOT EDIT.
    # Run ./.evergreen/update-evergreen-configs to regenerate this file.

  BANNER

  # Looks for a template in .evergreen/config with the given
  # base name, and 'yml.erb' as the extension. Processes that
  # template via ERB and writes the result to .evergreen with
  # the same basename, and a 'yml' extension.
  #
  # @param [ String ] name the name of the config to build.
  def build(name)
    output_path = File.join(__dir__, "#{name}.yml")
    File.write(output_path, GENERATED_BANNER + template(name, params: { header: false }))
  end

  # Reads the config template with the given name, processes it via
  # ERB, and returns the result.
  #
  # @param [ String ] name the (base) name of the template
  #
  # @return [ String ] the processed template
  def template(name, params: {})
    source_file = template_path(name)
    header_for(source_file, params.fetch(:header, true)) +
      ERB.new(File.read(source_file), trim_mode: '<>').result(binding).strip +
      "\n"
  end

  # Returns the path to the config template with the given base name.
  #
  # @param [ String ] name the base name of the template
  #
  # @return [ String ] the path to the template with the given name.
  def template_path(name)
    File.join(__dir__, 'config', "#{name}.yml.erb")
  end

  # Returns a banner to be used as a header in the config file,
  # naming the given source file. This makes it easier to look at
  # the generated config file and know where to look if something
  # needs to be changed.
  #
  # @param [ String ] source_file the path to the source file
  # @param [ true | false ] generate_header whether to return a header
  #   banner or not.
  #
  # @return [ String ] the header banner (or an empty string if
  #   generate_header is false)
  def header_for(source_file, generate_header)
    return '' unless generate_header

    root_path = File.expand_path('..', __dir__)
    simplified_path = source_file.sub(/^#{root_path}\//, '')

    <<~HEADER

      # -----------------------------------------------
      # #{simplified_path}
      # -----------------------------------------------

    HEADER
  end

  # these are used for testing against a few recent ruby versions
  def recent_rubies
    @recent_rubies ||= %w[ ruby-3.2 ruby-3.1 jruby-9.4 ]
  end

  # the most recently released, stable version of Ruby (make sure this
  # version is being built by 10gen/mongo-ruby-toolchain)
  def latest_mri_ruby
    "ruby-3.2"
  end

  # this is a list of the most most recent 3.x and 2.x MRI ruby versions
  def sample_mri_rubies
    @sample_mri_rubies ||= %w[ ruby-3.2 ruby-2.7 ]
  end

  # same as `sample_mri_rubies`, but without the `latest_mri_ruby` entry.
  def sample_without_latest
    @sample_without_latest ||= sample_mri_rubies.reject { |v| v == latest_mri_ruby }
  end

  # as above, but including the most recent JRuby release
  def sample_rubies
    @sample_rubies ||= sample_mri_rubies + %w[ jruby-9.4 ]
  end

  # older Ruby versions provided by 10gen/mongo-ruby-toolchain
  def older_rubies
    @older_rubies ||= %w[ ruby-3.0 ruby-2.7 ruby-2.6 ]
  end

  # all supported JRuby versions provided by 10gen/mongo-ruby-toolchain
  def jrubies
    @jrubies ||= %w[ jruby-9.4 jruby-9.3 ]
  end

  # all supported MRI ruby versions
  def supported_mri_rubies
    @supported_mri_rubies ||= %w[
      ruby-3.2 ruby-3.1 ruby-3.0
      ruby-2.7 ruby-2.6
    ]
  end

  # all supported ruby versions (MRI & JRuby)
  def supported_rubies
    @supported_rubies ||= supported_mri_rubies + jrubies
  end
end

ConfigProcessor.build 'config'