feat: aptible config:get cmd (#330)

Dockerfile

@@ -0,0 +1,10 @@
+FROM ruby:2.7.8
+
+WORKDIR /app
+COPY . /app
+
+RUN ./cleanup_bundler
+RUN gem install bundler -v '< 2'
+RUN bundle install
+
+CMD ["/app/bin/aptible"]

README.md

@@ -37,6 +37,7 @@ Commands:
   aptible backup:restore BACKUP_ID [--environment ENVIRONMENT_HANDLE] [--handle HANDLE] [--container-size SIZE_MB] [--disk-size SIZE_GB] [--key-arn KEY_ARN]                                                                                                                                                                                                    # Restore a backup
   aptible config                                                                                                                                                                                                                                                                                                                                                # Print an app's current configuration
   aptible config:add [VAR1=VAL1] [VAR2=VAL2] [...]                                                                                                                                                                                                                                                                                                              # Add an ENV variable to an app
+  aptible config:get [VAR1]                                                                                                                                                                                                                                                                                                                                     # Print a specific key within an app's current configuration
   aptible config:rm [VAR1] [VAR2] [...]                                                                                                                                                                                                                                                                                                                         # Remove an ENV variable from an app
   aptible config:set [VAR1=VAL1] [VAR2=VAL2] [...]                                                                                                                                                                                                                                                                                                              # Add an ENV variable to an app
   aptible config:unset [VAR1] [VAR2] [...]                                                                                                                                                                                                                                                                                                                      # Remove an ENV variable from an app

docker-compose.yml

@@ -0,0 +1,10 @@
+services:
+  # docker compose run cli bash
+  # export APTIBLE_ACCESS_TOKEN=xxx
+  # bundle exec ./bin/aptible help
+  cli:
+    build: .
+    volumes:
+      - type: bind
+        source: .
+        target: /app

lib/aptible/cli/subcommands/config.rb

@@ -29,6 +29,23 @@ def config
               end
             end
 
+            desc 'config:get [VAR1]',
+                 "Print a specific key within an app's current configuration"
+            app_options
+            define_method 'config:get' do |*args|
+              app = ensure_app(options)
+              config = app.current_configuration
+              env = config ? config.env : {}
+
+              Formatter.render(Renderer.current) do |root|
+                key = args[0]
+                value = env
+                        .select { |k| k == key }
+                        .map { |_, v| v }
+                root.value(value)
+              end
+            end
+
             desc 'config:add [VAR1=VAL1] [VAR2=VAL2] [...]',
                  'Add an ENV variable to an app'
             app_options

spec/aptible/cli/subcommands/config_spec.rb

@@ -57,6 +57,28 @@
     end
   end
 
+  describe '#config:get' do
+    it 'should show single environment variable specified' do
+      app.current_configuration = Fabricate(
+        :configuration, app: app, env: { 'FOO' => 'BAR', 'QUX' => 'two words' }
+      )
+      subject.send('config:get', 'FOO')
+
+      expect(captured_output_text).to match(/BAR/)
+      expect(captured_output_text).not_to match(/two\\ words/)
+      expect(captured_output_json).to match_array(['BAR'])
+    end
+
+    it 'should show empty line when env var not found' do
+      app.current_configuration = Fabricate(
+        :configuration, app: app, env: { 'FOO' => 'BAR', 'QUX' => 'two words' }
+      )
+      subject.send('config:get', 'MIZ')
+
+      expect(captured_output_text).to eq('')
+    end
+  end
+
   describe '#config:set' do
     it 'sets environment variables' do
       expect(app).to receive(:create_operation!)