Support environment specific credentials file. (#33521)

For `production` environment look first for `config/credentials/production.yml.enc` file that can be decrypted by
`ENV["RAILS_MASTER_KEY"]` or `config/credentials/production.key` master key.
Edit given environment credentials file by command `rails credentials:edit --environment production`.
Default behavior can be overwritten by setting `config.credentials.content_path` and `config.credentials.key_path`.

7 files changed, 163 insertions, 29 deletions

diff --git a/railties/CHANGELOG.md b/railties/CHANGELOG.md
index b916fda1cb..691e599ddb 100644
--- a/railties/CHANGELOG.md
+++ b/railties/CHANGELOG.md
@@ -1,3 +1,12 @@
+*   Support environment specific credentials file.
+
+    For `production` environment look first for `config/credentials/production.yml.enc` file that can be decrypted by
+    `ENV["RAILS_MASTER_KEY"]` or `config/credentials/production.key` master key.
+    Edit given environment credentials file by command `rails credentials:edit --environment production`.
+    Default paths can be overwritten by setting `config.credentials.content_path` and `config.credentials.key_path`.
+
+    *Wojciech Wnętrzak*
+
 *   Make `ActiveSupport::Cache::NullStore` the default cache store in the test environment.
 
     *Michael C. Nelson*
diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
index 26ed195dcc..656786246d 100644
--- a/railties/lib/rails/application.rb
+++ b/railties/lib/rails/application.rb
@@ -438,8 +438,12 @@ module Rails
     # Decrypts the credentials hash as kept in +config/credentials.yml.enc+. This file is encrypted with
     # the Rails master key, which is either taken from <tt>ENV["RAILS_MASTER_KEY"]</tt> or from loading
     # +config/master.key+.
+    # If specific credentials file exists for current environment, it takes precedence, thus for +production+
+    # environment look first for +config/credentials/production.yml.enc+ with master key taken
+    # from <tt>ENV["RAILS_MASTER_KEY"]</tt> or from loading +config/credentials/production.key+.
+    # Default behavior can be overwritten by setting +config.credentials.content_path+ and +config.credentials.key_path+.
     def credentials
-      @credentials ||= encrypted("config/credentials.yml.enc")
+      @credentials ||= encrypted(config.credentials.content_path, key_path: config.credentials.key_path)
     end
 
     # Shorthand to decrypt any encrypted configurations or files.
diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
index f4cbd2b9d0..eae902a938 100644
--- a/railties/lib/rails/application/configuration.rb
+++ b/railties/lib/rails/application/configuration.rb
@@ -17,7 +17,7 @@ module Rails
                     :session_options, :time_zone, :reload_classes_only_on_change,
                     :beginning_of_week, :filter_redirect, :x, :enable_dependency_loading,
                     :read_encrypted_secrets, :log_level, :content_security_policy_report_only,
-                    :content_security_policy_nonce_generator, :require_master_key
+                    :content_security_policy_nonce_generator, :require_master_key, :credentials
 
       attr_reader :encoding, :api_only, :loaded_config_version
 
@@ -60,6 +60,9 @@ module Rails
         @content_security_policy_nonce_generator = nil
         @require_master_key                      = false
         @loaded_config_version                   = nil
+        @credentials                             = ActiveSupport::OrderedOptions.new
+        @credentials.content_path                = default_credentials_content_path
+        @credentials.key_path                    = default_credentials_key_path
       end
 
       def load_defaults(target_version)
@@ -273,6 +276,27 @@ module Rails
           true
         end
       end
+
+      private
+        def credentials_available_for_current_env?
+          File.exist?("#{root}/config/credentials/#{Rails.env}.yml.enc")
+        end
+
+        def default_credentials_content_path
+          if credentials_available_for_current_env?
+            File.join(root, "config", "credentials", "#{Rails.env}.yml.enc")
+          else
+            File.join(root, "config", "credentials.yml.enc")
+          end
+        end
+
+        def default_credentials_key_path
+          if credentials_available_for_current_env?
+            File.join(root, "config", "credentials", "#{Rails.env}.key")
+          else
+            File.join(root, "config", "master.key")
+          end
+        end
     end
   end
 end
diff --git a/railties/lib/rails/commands/credentials/USAGE b/railties/lib/rails/commands/credentials/USAGE
index ea429f58d8..6b33d1ab74 100644
--- a/railties/lib/rails/commands/credentials/USAGE
+++ b/railties/lib/rails/commands/credentials/USAGE
@@ -38,3 +38,12 @@ the encrypted credentials.
 When the temporary file is next saved the contents are encrypted and written to
 `config/credentials.yml.enc` while the file itself is destroyed to prevent credentials
 from leaking.
+
+=== Environment Specific Credentials
+
+It is possible to have credentials for each environment. If the file for current environment exists it will take
+precedence over `config/credentials.yml.enc`, thus for `production` environment first look for
+`config/credentials/production.yml.enc` that can be decrypted using master key taken from `ENV["RAILS_MASTER_KEY"]`
+or stored in `config/credentials/production.key`.
+To edit given file use command `rails credentials:edit --environment production`
+Default paths can be overwritten by setting `config.credentials.content_path` and `config.credentials.key_path`.
diff --git a/railties/lib/rails/commands/credentials/credentials_command.rb b/railties/lib/rails/commands/credentials/credentials_command.rb
index 65c5218fc8..97e51786e7 100644
--- a/railties/lib/rails/commands/credentials/credentials_command.rb
+++ b/railties/lib/rails/commands/credentials/credentials_command.rb
@@ -8,6 +8,9 @@ module Rails
     class CredentialsCommand < Rails::Command::Base # :nodoc:
       include Helpers::Editor
 
+      class_option :environment, aliases: "-e", type: :string,
+        desc: "Uses credentials from config/credentials/:environment.yml.enc encrypted by config/credentials/:environment.key key"
+
       no_commands do
         def help
           say "Usage:\n  #{self.class.banner}"
@@ -20,58 +23,78 @@ module Rails
         require_application_and_environment!
 
         ensure_editor_available(command: "bin/rails credentials:edit") || (return)
-        ensure_master_key_has_been_added if Rails.application.credentials.key.nil?
-        ensure_credentials_have_been_added
+
+        encrypted = Rails.application.encrypted(content_path, key_path: key_path, env_key: env_key)
+
+        ensure_encryption_key_has_been_added(key_path) if encrypted.key.nil?
+        ensure_encrypted_file_has_been_added(content_path, key_path)
 
         catch_editing_exceptions do
-          change_credentials_in_system_editor
+          change_encrypted_file_in_system_editor(content_path, key_path, env_key)
         end
 
-        say "New credentials encrypted and saved."
+        say "File encrypted and saved."
+      rescue ActiveSupport::MessageEncryptor::InvalidMessage
+        say "Couldn't decrypt #{content_path}. Perhaps you passed the wrong key?"
       end
 
       def show
         require_application_and_environment!
 
-        say Rails.application.credentials.read.presence || missing_credentials_message
+        encrypted = Rails.application.encrypted(content_path, key_path: key_path, env_key: env_key)
+
+        say encrypted.read.presence || missing_encrypted_message(key: encrypted.key, key_path: key_path, file_path: content_path)
       end
 
       private
-        def ensure_master_key_has_been_added
-          master_key_generator.add_master_key_file
-          master_key_generator.ignore_master_key_file
+        def content_path
+          options[:environment] ? "config/credentials/#{options[:environment]}.yml.enc" : "config/credentials.yml.enc"
+        end
+
+        def key_path
+          options[:environment] ? "config/credentials/#{options[:environment]}.key" : "config/master.key"
+        end
+
+        def env_key
+          options[:environment] ? "RAILS_#{options[:environment].upcase}_KEY" : "RAILS_MASTER_KEY"
+        end
+
+
+        def ensure_encryption_key_has_been_added(key_path)
+          encryption_key_file_generator.add_key_file(key_path)
+          encryption_key_file_generator.ignore_key_file(key_path)
         end
 
-        def ensure_credentials_have_been_added
-          credentials_generator.add_credentials_file_silently
+        def ensure_encrypted_file_has_been_added(file_path, key_path)
+          encrypted_file_generator.add_encrypted_file_silently(file_path, key_path)
         end
 
-        def change_credentials_in_system_editor
-          Rails.application.credentials.change do |tmp_path|
+        def change_encrypted_file_in_system_editor(file_path, key_path, env_key)
+          Rails.application.encrypted(file_path, key_path: key_path, env_key: env_key).change do |tmp_path|
             system("#{ENV["EDITOR"]} #{tmp_path}")
           end
         end
 
 
-        def master_key_generator
+        def encryption_key_file_generator
           require "rails/generators"
-          require "rails/generators/rails/master_key/master_key_generator"
+          require "rails/generators/rails/encryption_key_file/encryption_key_file_generator"
 
-          Rails::Generators::MasterKeyGenerator.new
+          Rails::Generators::EncryptionKeyFileGenerator.new
         end
 
-        def credentials_generator
+        def encrypted_file_generator
           require "rails/generators"
-          require "rails/generators/rails/credentials/credentials_generator"
+          require "rails/generators/rails/encrypted_file/encrypted_file_generator"
 
-          Rails::Generators::CredentialsGenerator.new
+          Rails::Generators::EncryptedFileGenerator.new
         end
 
-        def missing_credentials_message
-          if Rails.application.credentials.key.nil?
-            "Missing master key to decrypt credentials. See `rails credentials:help`"
+        def missing_encrypted_message(key:, key_path:, file_path:)
+          if key.nil?
+            "Missing '#{key_path}' to decrypt credentials. See `rails credentials:help`"
           else
-            "No credentials have been added yet. Use `rails credentials:edit` to change that."
+            "File '#{file_path}' does not exist. Use `rails credentials:edit` to change that."
           end
         end
     end
diff --git a/railties/test/commands/credentials_test.rb b/railties/test/commands/credentials_test.rb
index 5b8b9e4eda..7842b0db61 100644
--- a/railties/test/commands/credentials_test.rb
+++ b/railties/test/commands/credentials_test.rb
@@ -55,6 +55,14 @@ class Rails::Command::CredentialsCommandTest < ActiveSupport::TestCase
     end
   end
 
+  test "edit command modifies file specified by environment option" do
+    assert_match(/access_key_id: 123/, run_edit_command(environment: "production"))
+    Dir.chdir(app_path) do
+      assert File.exist?("config/credentials/production.key")
+      assert File.exist?("config/credentials/production.yml.enc")
+    end
+  end
+
   test "show credentials" do
     assert_match(/access_key_id: 123/, run_show_command)
   end
@@ -70,17 +78,25 @@ class Rails::Command::CredentialsCommandTest < ActiveSupport::TestCase
     remove_file "config/master.key"
     add_to_config "config.require_master_key = false"
 
-    assert_match(/Missing master key to decrypt credentials/, run_show_command)
+    assert_match(/Missing 'config\/master\.key' to decrypt credentials/, run_show_command)
+  end
+
+  test "show command displays content specified by environment option" do
+    run_edit_command(environment: "production")
+
+    assert_match(/access_key_id: 123/, run_show_command(environment: "production"))
   end
 
   private
-    def run_edit_command(editor: "cat")
+    def run_edit_command(editor: "cat", environment: nil, **options)
       switch_env("EDITOR", editor) do
-        rails "credentials:edit"
+        args = environment ? ["--environment", environment] : []
+        rails "credentials:edit", args, **options
       end
     end
 
-    def run_show_command(**options)
-      rails "credentials:show", **options
+    def run_show_command(environment: nil, **options)
+      args = environment ? ["--environment", environment] : []
+      rails "credentials:show", args, **options
     end
 end
diff --git a/railties/test/credentials_test.rb b/railties/test/credentials_test.rb
new file mode 100644
index 0000000000..03370e0fc7
--- /dev/null
+++ b/railties/test/credentials_test.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require "isolation/abstract_unit"
+
+class Rails::CredentialsTest < ActiveSupport::TestCase
+  include ActiveSupport::Testing::Isolation
+
+  setup :build_app
+  teardown :teardown_app
+
+  test "reads credentials from environment specific path" do
+    with_credentials do |content, key|
+      Dir.chdir(app_path) do
+        Dir.mkdir("config/credentials")
+        File.write("config/credentials/production.yml.enc", content)
+        File.write("config/credentials/production.key", key)
+      end
+
+      app("production")
+
+      assert_equal "revealed", Rails.application.credentials.mystery
+    end
+  end
+
+  test "reads credentials from customized path and key" do
+    with_credentials do |content, key|
+      Dir.chdir(app_path) do
+        Dir.mkdir("config/credentials")
+        File.write("config/credentials/staging.yml.enc", content)
+        File.write("config/credentials/staging.key", key)
+      end
+
+      add_to_env_config("production", "config.credentials.content_path = config.root.join('config/credentials/staging.yml.enc')")
+      add_to_env_config("production", "config.credentials.key_path = config.root.join('config/credentials/staging.key')")
+      app("production")
+
+      assert_equal "revealed", Rails.application.credentials.mystery
+    end
+  end
+
+  private
+    def with_credentials
+      key = "2117e775dc2024d4f49ddf3aeb585919"
+      # secret_key_base: secret
+      # mystery: revealed
+      content = "vgvKu4MBepIgZ5VHQMMPwnQNsLlWD9LKmJHu3UA/8yj6x+3fNhz3DwL9brX7UA==--qLdxHP6e34xeTAiI--nrcAsleXuo9NqiEuhntAhw=="
+      yield(content, key)
+    end
+end