API client can retrieve env variables for a revision

[finishes #162994516]

Signed-off-by: Mona Mohebbi <[email protected]>

app/controllers/v3/app_revisions_controller.rb

@@ -5,6 +5,7 @@
 require 'actions/app_revisions_update'
 require 'presenters/v3/revision_presenter'
 require 'controllers/v3/mixins/app_sub_resource'
+require 'presenters/v3/revision_environment_variables_presenter'
 
 class AppRevisionsController < ApplicationController
   include AppSubResource
@@ -51,4 +52,15 @@ def update
 
     render status: :ok, json: Presenters::V3::RevisionPresenter.new(revision)
   end
+
+  def show_environment_variables
+    app, space, org = AppFetcher.new.fetch(hashed_params[:guid])
+    app_not_found! unless app && permission_queryer.can_read_from_space?(space.guid, org.guid)
+    unauthorized! unless permission_queryer.can_read_secrets_in_space?(space.guid, org.guid)
+
+    revision = RevisionModel.find(guid: hashed_params[:revision_guid])
+    resource_not_found!(:revision) unless revision && revision.app_guid == app.guid
+
+    render status: :ok, json: Presenters::V3::RevisionEnvironmentVariablesPresenter.new(revision)
+  end
 end

app/presenters/v3/app_environment_variables_presenter.rb

@@ -14,17 +14,19 @@ def to_hash
             links: build_links
           }
 
-          if !app.environment_variables.nil?
-            app.environment_variables.each do |key, value|
-              result[:var][key.to_sym] = value
-            end
+          env_vars&.each do |key, value|
+            result[:var][key.to_sym] = value
           end
 
           result
         end
 
         private
 
+        def env_vars
+          app&.environment_variables
+        end
+
         def build_links
           url_builder = VCAP::CloudController::Presenters::ApiUrlBuilder.new
 

app/presenters/v3/revision_environment_variables_presenter.rb

@@ -0,0 +1,45 @@
+require 'presenters/v3/app_environment_variables_presenter'
+require 'presenters/v3/base_presenter'
+
+module VCAP::CloudController
+  module Presenters
+    module V3
+      class RevisionEnvironmentVariablesPresenter
+        attr_reader :revision
+
+        def initialize(revision)
+          @revision = revision
+        end
+
+        def to_hash
+          result = {
+            var: {},
+            links: build_links
+          }
+
+          env_vars&.each do |key, value|
+            result[:var][key.to_sym] = value
+          end
+
+          result
+        end
+
+        private
+
+        def env_vars
+          revision&.environment_variables
+        end
+
+        def build_links
+          url_builder = VCAP::CloudController::Presenters::ApiUrlBuilder.new
+
+          {
+            self: { href: url_builder.build_url(path: "/v3/apps/#{revision.app.guid}/revisions/#{revision.guid}/environment_variables") },
+            revision: { href: url_builder.build_url(path: "/v3/apps/#{revision.app.guid}/revisions/#{revision.guid}") },
+            app:  { href: url_builder.build_url(path: "/v3/apps/#{revision.app.guid}") }
+          }
+        end
+      end
+    end
+  end
+end

config/routes.rb

@@ -29,6 +29,7 @@
   # app revisions
   get '/apps/:guid/revisions', to: 'app_revisions#index'
   get '/apps/:guid/revisions/:revision_guid', to: 'app_revisions#show'
+  get '/apps/:guid/revisions/:revision_guid/environment_variables', to: 'app_revisions#show_environment_variables'
   patch '/apps/:guid/revisions/:revision_guid', to: 'app_revisions#update'
 
   # environment variables

spec/request/revisions_spec.rb

@@ -222,4 +222,32 @@
       )
     end
   end
+
+  describe 'GET /v3/apps/:guid/revision/:revguid/environment_variables' do
+    let!(:revision2) { VCAP::CloudController::RevisionModel.make(
+      app: app_model,
+      version: 43,
+      environment_variables: { 'key' => 'value' },
+    )
+    }
+
+    it 'gets the environment variables for the revision' do
+      get "/v3/apps/#{app_model.reload.guid}/revisions/#{revision2.guid}/environment_variables", nil, user_header
+      expect(last_response.status).to eq(200), last_response.body
+
+      parsed_response = MultiJson.load(last_response.body)
+      expect(parsed_response).to be_a_response_like(
+        {
+          'var' => {
+            'key' => 'value'
+          },
+          'links' => {
+            'self' => { 'href' => "#{link_prefix}/v3/apps/#{app_model.guid}/revisions/#{revision2.guid}/environment_variables" },
+            'revision' => { 'href' => "#{link_prefix}/v3/apps/#{app_model.guid}/revisions/#{revision2.guid}" },
+            'app' => { 'href' => "#{link_prefix}/v3/apps/#{app_model.guid}" },
+          }
+        }
+      )
+    end
+  end
 end

spec/support/fakes/blueprints.rb

@@ -604,6 +604,7 @@ module VCAP::CloudController
   end
 
   RevisionModel.blueprint do
+    app { AppModel.make }
   end
 
   TestModel.blueprint do

spec/unit/controllers/v3/app_revisions_controller_spec.rb

@@ -354,4 +354,60 @@
       end
     end
   end
+
+  describe '#show_environment_variables' do
+    let!(:droplet) { VCAP::CloudController::DropletModel.make }
+    let!(:app_model) { VCAP::CloudController::AppModel.make(droplet: droplet) }
+    let!(:space) { app_model.space }
+    let(:user) { VCAP::CloudController::User.make }
+    let(:revision) { VCAP::CloudController::RevisionModel.make(
+      app: app_model,
+      version: 808,
+      droplet_guid: droplet.guid,
+      environment_variables: { 'key' => 'value' },
+    )
+    }
+
+    before do
+      set_current_user(user)
+      allow_user_read_access_for(user, spaces: [space])
+      allow_user_secret_access(user, space: space)
+    end
+
+    it 'returns 200 and shows environment_variables' do
+      get :show_environment_variables, params: { guid: app_model.guid, revision_guid: revision.guid }
+
+      expect(response.status).to eq(200)
+      expect(parsed_body['var']).to eq({ 'key' => 'value' })
+    end
+
+    context 'when retrieving env variables for revision that do not exist' do
+      it '404s' do
+        get :show_environment_variables, params: { guid: app_model.guid, revision_guid: 'nonsense' }
+        expect(response.status).to eq(404)
+      end
+    end
+
+    context 'when access to the space is restricted' do
+      before do
+        disallow_user_read_access(user, space: space)
+      end
+
+      it '404s' do
+        get :show_environment_variables, params: { guid: app_model.guid, revision_guid: 'nonsense' }
+        expect(response.status).to eq(404)
+      end
+    end
+
+    context 'when access is restricted' do
+      before do
+        disallow_user_secret_access(user, space: space)
+      end
+
+      it '403s' do
+        get :show_environment_variables, params: { guid: app_model.guid, revision_guid: 'nonsense' }
+        expect(response.status).to eq(403)
+      end
+    end
+  end
 end

spec/unit/presenters/v3/revision_environment_variables_presenter_spec.rb

@@ -0,0 +1,37 @@
+require 'spec_helper'
+require 'presenters/v3/revision_environment_variables_presenter'
+
+module VCAP::CloudController::Presenters::V3
+  RSpec.describe RevisionEnvironmentVariablesPresenter do
+    let(:revision) do
+      VCAP::CloudController::RevisionModel.make(
+        environment_variables: { 'CUSTOM_ENV_VAR' => 'hello' },
+      )
+    end
+
+    subject(:presenter) { RevisionEnvironmentVariablesPresenter.new(revision) }
+
+    describe '#to_hash' do
+      let(:result) { presenter.to_hash }
+
+      it 'presents the app environment variables as json' do
+        expect(result).to eq({
+          var: {
+            CUSTOM_ENV_VAR: 'hello'
+          },
+          links: {
+            self: {
+              href: "#{link_prefix}/v3/apps/#{revision.app.guid}/revisions/#{revision.guid}/environment_variables",
+            },
+            revision: {
+              href: "#{link_prefix}/v3/apps/#{revision.app.guid}/revisions/#{revision.guid}",
+            },
+            app: {
+              href: "#{link_prefix}/v3/apps/#{revision.app.guid}",
+            },
+          }
+        })
+      end
+    end
+  end
+end