Show generic app install errors in the dialog

dashboard/src/components/AppInstallDialog.vue

@@ -60,6 +60,9 @@ const secondaryDomains = ref({});
 const upstreamUri = ref('');
 
 async function submit() {
+  formError.value = {};
+  busy.value = true;
+
   const config = {
     subdomain: location.value,
     domain: domain.value.domain,
@@ -88,25 +91,23 @@ async function submit() {
   }
   config.secondaryDomains = finalSecondaryDomains;
 
-  if (manifest.value.id === PROXY_APP_ID) {
-    config.upstreamUri = upstreamUri.value;
-  }
+  if (manifest.value.id === PROXY_APP_ID) config.upstreamUri = upstreamUri.value;
 
-  busy.value = true;
-  const error = await appsModel.install(manifest.value, config);
-  busy.value = false;
+  const [error] = await appsModel.install(manifest.value, config);
 
   if (!error) {
     dialog.value.close();
     return window.location.href = '#/apps';
   }
 
-  formError.value = {};
+  busy.value = false;
   if (error.status === 'Conflict' && error.message.indexOf('port') !== -1) {
     const match = error.message.match(/.*port.(.*)/);
     formError.value.port = match ? parseInt(match[1]) : null;
   } else if (error.status === 'Conflict' && error.message.indexOf('primary location') !== -1) {
     formError.value.location = true;
+  } else if (error.status === 412) {
+    formError.value.generic = error.body.message;
   } else {
     console.error('Failed to install:', error);
   }
@@ -182,6 +183,8 @@ defineExpose({
           <div class="description" v-html="description"></div>
         </div>
         <div v-else-if="step === STEP.INSTALL">
+          <div class="text-danger" v-if="formError.generic">{{ formError.generic }}</div>
+
           <form @submit.prevent="submit()" autocomplete="off">
             <fieldset :disabled="busy">
               <input style="display: none;" type="submit" :disabled="!formValid" />