Handle UaaUnavailable errors that occur when fetching creds from CredHub

- These errors are now converted into 'UaaUnavailable' flavored
  `CloudController::Errors::ApiError`s

[#150753759]

Signed-off-by: Annie Sing <[email protected]>

Author: tcdowney

app/collection_transformers/credhub_credential_populator.rb

@@ -16,6 +16,8 @@ def transform(service_keys, _opts={})
       end
     rescue Credhub::Error
       raise CloudController::Errors::ApiError.new_from_details('ServiceKeyCredentialStoreUnavailable')
+    rescue UaaUnavailable
+      raise CloudController::Errors::ApiError.new_from_details('UaaUnavailable')
     end
   end
 end

spec/unit/collection_transformers/credhub_credential_populator_spec.rb

@@ -19,7 +19,7 @@ module VCAP::CloudController
 
       subject { CredhubCredentialPopulator.new(fake_credhub_client) }
 
-      context 'when credhub responds successfully' do
+      context 'when CredHub responds successfully' do
         before do
           allow(fake_credhub_client).to receive(:get_credential_by_name).with(service_keys[0].credhub_reference).and_return(credhub_cred_1)
           allow(fake_credhub_client).to receive(:get_credential_by_name).with(service_keys[2].credhub_reference).and_return(credhub_cred_2)
@@ -38,7 +38,7 @@ module VCAP::CloudController
         end
       end
 
-      context 'when credhub errors' do
+      context 'when any Credhub::Error occurs' do
         before do
           allow(fake_credhub_client).to receive(:get_credential_by_name).and_raise(Credhub::Error)
         end
@@ -47,6 +47,16 @@ module VCAP::CloudController
           expect { subject.transform(service_keys) }.to raise_error(CloudController::Errors::ApiError, /Credential store is unavailable/)
         end
       end
+
+      context 'when a VCAP::CloudController::UaaUnavailable error occurs' do
+        before do
+          allow(fake_credhub_client).to receive(:get_credential_by_name).and_raise(UaaUnavailable)
+        end
+
+        it 'raises CloudController::Errors::ApiError "UaaUnavailable"' do
+          expect { subject.transform(service_keys) }.to raise_error(CloudController::Errors::ApiError, /UAA service is currently unavailable/)
+        end
+      end
     end
   end
 end

spec/unit/controllers/services/service_keys_controller_spec.rb

@@ -499,6 +499,15 @@ def verify_not_found_response(service_key_guid)
           expect(last_response.status).to eq(503)
           expect(decoded_response['description']).to eq('Credential store is unavailable')
         end
+
+        it 'returns 503 when uaa is unavailable' do
+          allow(fake_credhub_client).to receive(:get_credential_by_name).and_raise(UaaUnavailable)
+
+          get "/v2/service_keys/#{service_key.guid}"
+
+          expect(last_response.status).to eq(503)
+          expect(decoded_response['description']).to eq('The UAA service is currently unavailable')
+        end
       end
 
       context 'when the key is not a CredHub reference' do