Add support for 3-tier database configurations on development

README.md

@@ -103,7 +103,7 @@ heroku git:remote -r staging -a your-staging-app
 heroku git:remote -r production -a your-production-app
 ```
 * There is a `config/database.yml` file that can be parsed as YAML for
-  `['development']['database']`.
+  `['development']['database']` or, alternatively, `['development']['primary']['database']` for multi-database configurations.
 
 Pipelines
 ---------

lib/parity/backup.rb

@@ -5,6 +5,7 @@ class Backup
     BLANK_ARGUMENTS = "".freeze
     DATABASE_YML_RELATIVE_PATH = "config/database.yml".freeze
     DEVELOPMENT_ENVIRONMENT_KEY_NAME = "development".freeze
+    PRIMARY_DATABASE_KEY_NAME = "primary".freeze
     DATABASE_KEY_NAME = "database".freeze
 
     def initialize(args)
@@ -108,9 +109,15 @@ def remote_db_backup_url
     end
 
     def development_db
-      YAML.load(database_yaml_file).
-        fetch(DEVELOPMENT_ENVIRONMENT_KEY_NAME).
-        fetch(DATABASE_KEY_NAME)
+      db_configuration = YAML.safe_load(database_yaml_file, aliases: true).
+        fetch(DEVELOPMENT_ENVIRONMENT_KEY_NAME)
+
+      if db_configuration.key?(PRIMARY_DATABASE_KEY_NAME)
+        db_configuration[PRIMARY_DATABASE_KEY_NAME].
+          fetch(DATABASE_KEY_NAME)
+      else
+        db_configuration.fetch(DATABASE_KEY_NAME)
+      end
     end
 
     def database_yaml_file

spec/fixtures/database_three_tier.yml

@@ -0,0 +1,8 @@
+development:
+  primary:
+    database: parity_development
+    username: user
+  primary_replica:
+    database: parity_development
+    username: user_readonly
+    replica: true

spec/parity/backup_spec.rb

@@ -169,6 +169,32 @@
         to have_received(:system).
         with(delete_local_temp_backup_command)
     end
+
+    it "is able to load a database.yml file with 3-tier configuration" do
+      allow(IO).to receive(:read).and_return(database_fixture_three_tier)
+      allow(Kernel).to receive(:system)
+
+      Parity::Backup.new(
+        from: "production",
+        to: "development",
+      ).restore
+
+      expect(Kernel).
+        to have_received(:system).
+        with(make_temp_directory_command)
+      expect(Kernel).
+        to have_received(:system).
+        with(download_remote_database_command)
+      expect(Kernel).
+        to have_received(:system).
+        with(drop_development_database_drop_command)
+      expect(Kernel).
+        to have_received(:system).
+        with(restore_from_local_temp_backup_command(cores: 1))
+      expect(Kernel).
+        to have_received(:system).
+        with(delete_local_temp_backup_command)
+    end
   end
 
   it "restores backups to staging from production" do
@@ -231,6 +257,10 @@ def database_fixture_with_erb
     IO.read(fixture_path("database_with_erb.yml"))
   end
 
+  def database_fixture_three_tier
+    IO.read(fixture_path("database_three_tier.yml"))
+  end
+
   def fixture_path(filename)
     File.join(File.dirname(__FILE__), "..", "fixtures", filename)
   end