v3(services): Only update expected binding fields when creating a

binding

OSBAPI spec outlines the broker expected response for a create binding
and indicates that any other field return by brokers should be ignored.
v2 has this behaviour but was missing in v3 and was causing failures
when the broker response includes attributes that are not part of the CC
DB. This is so we don't try to update any other fields.

[#175662475](https://www.pivotaltracker.com/story/show/175662475)

Author: pivotal-marcela-campo

app/actions/service_credential_binding_app_create.rb

@@ -17,6 +17,8 @@ def initialize(user_audit_info, audit_hash)
         @audit_hash = audit_hash
       end
 
+      PERMITTED_BINDING_ATTRIBUTES = [:credentials, :syslog_drain_url, :volume_mounts].freeze
+
       def precursor(service_instance, app: nil, name: nil, volume_mount_services_enabled: false)
         validate!(service_instance, app, volume_mount_services_enabled)
 
@@ -45,7 +47,7 @@ def precursor(service_instance, app: nil, name: nil, volume_mount_services_enabl
 
       def complete_binding_and_save(binding, binding_details, last_operation)
         binding.save_with_attributes_and_new_operation(
-          binding_details,
+          binding_details.symbolize_keys().slice(*PERMITTED_BINDING_ATTRIBUTES),
           {
             type: 'create',
             state: last_operation[:state],

spec/request/service_credential_bindings_spec.rb

@@ -1382,7 +1382,18 @@ def check_filtered_bindings(*bindings)
                 {
                   syslog_drain_url: syslog_drain_url,
                   credentials: credentials,
-                  parameters: parameters
+                  parameters: parameters,
+                  service_id:'extra-field-service_id',
+                  plan_id:'extra-field-plan_id',
+                  name: 'extra-field-name',
+                  bind_resource:{
+                    app_guid:'extra-field',
+                    space_guid:'extra-field'
+                  },
+                  context:
+                    {
+                      platform:'extra-field',
+                    }
                 }
               end
 
@@ -1409,11 +1420,12 @@ def check_filtered_bindings(*bindings)
                 expect(job.state).to eq(VCAP::CloudController::PollableJobModel::COMPLETE_STATE)
               end
 
-              it 'updates the binding details with the fetch binding response' do
+              it 'updates the binding details with the fetch binding response ignoring extra fields' do
                 execute_all_jobs(expected_successes: 1, expected_failures: 0)
 
                 expect(binding.reload.syslog_drain_url).to eq(syslog_drain_url)
                 expect(binding.credentials).to eq(credentials.with_indifferent_access)
+                expect(binding.name).to eq('some-name')
               end
 
               context 'fetching binding fails ' do

spec/unit/actions/service_credential_binding_app_create_spec.rb

@@ -258,10 +258,23 @@ module V3
       end
 
       describe '#poll' do
-        let(:binding) { action.precursor(service_instance, app: app) }
+        let(:binding) { action.precursor(service_instance, app: app, name: 'original-name') }
         let(:credentials) { { 'password' => 'rennt', 'username' => 'lola' } }
+        let(:volume_mounts) { [{
+            'driver' => 'cephdriver',
+            'container_dir' => '/data/images',
+            'mode' => 'r',
+            'device_type' => 'shared',
+            'device' => {
+              'volume_id' => 'bc2c1eab-05b9-482d-b0cf-750ee07de311',
+              'mount_config' => {
+                'key' => 'value'
+              }
+            }
+          }]
+        }
         let(:syslog_drain_url) { 'https://drain.syslog.example.com/runlolarun' }
-        let(:fetch_binding_response) { { credentials: credentials, syslog_drain_url: syslog_drain_url } }
+        let(:fetch_binding_response) { { credentials: credentials, syslog_drain_url: syslog_drain_url, volume_mounts: volume_mounts, name: 'updated-name' } }
 
         it_behaves_like 'polling service binding creation'
 
@@ -302,14 +315,16 @@ module V3
             let(:description) { Sham.description }
             let(:state) { 'succeeded' }
 
-            it 'fetches the service binding and updates the route_services_url' do
+            it 'fetches the service binding and updates only the credentials, volume_mounts and syslog_drain_url' do
               action.poll(binding)
 
               expect(broker_client).to have_received(:fetch_service_binding).with(binding)
 
               binding.reload
               expect(binding.credentials).to eq(credentials)
               expect(binding.syslog_drain_url).to eq(syslog_drain_url)
+              expect(binding.volume_mounts).to eq(volume_mounts)
+              expect(binding.name).to eq('original-name')
             end
 
             it 'creates an audit event' do