デプロイ時にcredentials.yml.enc周りのエラー

Question

rails6.1
herokuにデプロイ中に以下のエラーが出て失敗しました。

remote:        Running: rake assets:precompile
remote:        rake aborted!
remote:        NoMethodError: undefined method `[]' for nil:NilClass
remote:        /tmp/build_414aed34/config/initializers/carrierwave.rb:11:in `block in <main>'
remote:        /tmp/build_414aed34/vendor/bundle/ruby/3.0.0/gems/carrierwave-2.2.0/lib/carrierwave/uploader/configuration.rb:174:in `configure'
remote:        /tmp/build_414aed34/vendor/bundle/ruby/3.0.0/gems/carrierwave-2.2.0/lib/carrierwave.rb:14:in `configure'
remote:        /tmp/build_414aed34/config/initializers/carrierwave.rb:5:in `<main>'
remote:        /tmp/build_414aed34/vendor/bundle/ruby/3.0.0/gems/bootsnap-1.7.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:59:in `load'
remote:        /tmp/build_414aed34/vendor/bundle/ruby/3.0.0/gems/bootsnap-1.7.2/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb

carriewaveによる画像の保存先を設定し、デプロイしたら今回のエラーでした。

「aws_access_key_id: Rails.application.credentials.aws[:access_key_id],」の行でエラーになってるようです。

config\initializers\carrierwave.rb

require 'carrierwave/storage/abstract'
require 'carrierwave/storage/file'
require 'carrierwave/storage/fog'

CarrierWave.configure do |config|
  if Rails.env.production?
    config.storage = :fog
    config.fog_provider = 'fog/aws'
    config.fog_credentials = {
      provider: 'AWS',
      aws_access_key_id: Rails.application.credentials.aws[:access_key_id],
      aws_secret_access_key: Rails.application.credentials.aws[:secret_access_key],
      region: 'ap-northeast-1'
    }

    config.fog_directory  = 'xxxx'
    config.asset_host = 'https://s3-ap-northeast-1.amazonaws.com/xxxx'
  else
    config.storage :file
    config.enable_processing = false if Rails.env.test?
  end

  
end

ローカル環境では特にエラーなく動いてます。

何が原因でデプロイ失敗してるのか分かりません。
先輩方教えていただけないでしょうか？

app\uploaders\image_uploader.rb

# require 'logger'
class ImageUploader < CarrierWave::Uploader::Base
    # Include RMagick or MiniMagick support:
    # include CarrierWave::RMagick
    # include CarrierWave::MiniMagick
    
    include CarrierWave::MiniMagick
    #process resize_to_limit: [100, 100]
    process resize_to_fill: [600, 600, "Center"]
    #process resize_to_fit: [200, 200]
    
    if Rails.env.development?
      storage :file
    elsif Rails.env.test?
      storage :file
    else
      storage :fog
    end
    
    # Override the directory where uploaded files will be stored.
    # This is a sensible default for uploaders that are meant to be mounted:
    def store_dir
      "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
    end
  
    # Provide a default URL as a default if there hasn't been a file uploaded:
    # def default_url(*args)
    #   # For Rails 3.1+ asset pipeline compatibility:
    #   # ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_'))
    #
    #   "/images/fallback/" + [version_name, "default.png"].compact.join('_')
    # end
  
    # Process files as they are uploaded:
    # process scale: [200, 300]
    #
    # def scale(width, height)
    #   # do something
    # end
  
    # Create different versions of your uploaded files:
     version :thumb do
       process resize_to_fit: [50, 50]
     end
  
    # Add a white list of extensions which are allowed to be uploaded.
    # For images you might use something like this:
    def extension_whitelist
      %w(jpg jpeg gif png)
    end
  
    # Override the filename of the uploaded files:
    # Avoid using model.id or version_name here, see uploader/store.rb for details.
  #   def filename
    
  #     logger = Logger.new(STDOUT)
  #     logger.debug "++++++ filename : #{original_filename}"
  
  #     #"something.jpg" if original_filename
  #     "#{secure_token}_#{original_filename}" if original_filename.present?
      
  #   end
    
  # protected
  #   def secure_token
  #     var = :"@#{mounted_as}_secure_token"
  #     model.instance_variable_get(var) or model.instance_variable_set(var, SecureRandom.uuid)
  #   end
    
end
  

credentials.yml.encへキーは入力済みで、
railsコンソールから取得できました。

[1] pry(main)> Rails.application.credentials.aws[:access_key_id]
=> "xxxxxxxxxxxxxxxx"

teratail内に同一のエラーメッセージがありました。
参考に、herokuに環境変数の設定しましたが、相変わらずでした。
https://teratail.com/questions/248349

Answer 1

https://teratail.com/questions/163759