ui: Gracefully recover from non-existent DC errors (#11077)

* ui: Gracefully recover from non-existent DC errors

This PR fixes what happens in the UI if you try to navigate to a non-existing DC.

When we received a 500 error from an API response due to a non-existent DC, previously we would show a 404 error, which is what we were trying to convey. But in the spirit of the UI being a 'thin client', its probably best to just show the 500 error from the API response, which may help folks to debug any issues better.

* Automatically set the CONSUL_DATACENTER_LOCAL env var for testing

.changelog/11077.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+ui: Gracefully recover from non-existant DC errors 
+```

ui/packages/consul-ui/app/helpers/cached-model.js

@@ -0,0 +1,11 @@
+import Helper from '@ember/component/helper';
+import { getOwner } from '@ember/application';
+
+export default class CachedHelper extends Helper {
+  compute([model], hash) {
+    return () => {
+      const container = getOwner(this);
+      return container.lookup(`service:repository/${model}`).cached(hash);
+    };
+  }
+}

ui/packages/consul-ui/app/services/repository.js

@@ -99,6 +99,13 @@ export default class RepositoryService extends Service {
     return this.store.peekRecord(this.getModelName(), id);
   }
 
+  cached(params) {
+    const entries = Object.entries(params);
+    return this.store.peekAll(this.getModelName()).filter(item => {
+      return entries.every(([key, value]) => item[key] === value);
+    });
+  }
+
   // @deprecated
   findAllByDatacenter(params, configuration = {}) {
     return this.findAll(...arguments);

ui/packages/consul-ui/app/templates/application.hbs

@@ -58,24 +58,44 @@ as |source|>
 
 {{! Make sure we guess and default to the right params when not found }}
 {{#let
-  (or notfound.dc route.params.dc (env "CONSUL_DATACENTER_LOCAL"))
   (if (can "use partitions") (or route.params.partition notfound.partition token.Partition 'default') 'default')
   (if (can "use nspaces") (or route.params.nspace notfound.nspace token.Namespace 'default') 'default')
-as |dc partition nspace|}}
+as |partition nspace|}}
 
 {{! Make sure we have enough to show the app chrome}}
-{{!FIXME}}
+{{! Don't show anything until we have a list of DCs }}
-{{#if (gt dc.length 0)}}
+<DataSource
-
-    {{! Don't show anything until we have a list of DCs }}
-    <DataSource
   @src={{uri '/*/*/*/datacenters'}}
-    as |dcs|>
+as |dcs|>
 
+{{! Once we have a list of DCs make sure the DC we are asking for exists }}
+{{! If not use the DC that the UI is running in }}
 {{#let
+  (or
+
+    (get (object-at 0 (cached-model
+      'dc'
+        (hash
+          Name=notfound.dc
+        )
+    )) 'Name')
+
+    (get (object-at 0 (cached-model
+      'dc'
+        (hash
+          Name=route.params.dc
+        )
+    )) 'Name')
+
+    (env "CONSUL_DATACENTER_LOCAL")
+
+  )
+
   dcs.data
-as |dcs|}}
+
-  {{#if (and dcs nspace partition)}}
+as |dc dcs|}}
+
+  {{#if (and (gt dc.length 0) dcs nspace partition)}}
 
     {{! figure out our current DC and convert it to a model }}
     <DataSource
@@ -133,8 +153,7 @@ as |dcs|}}
     </DataSource>
   {{/if}}
 {{/let}}
-    </DataSource>
+</DataSource>
-{{/if}}
 {{/let}}
 {{/if}}
 </Route>

ui/packages/consul-ui/mock-api/v1/catalog/datacenters

@@ -2,7 +2,7 @@
   ${
     range(env('CONSUL_DATACENTER_COUNT', 10)).map((item, i) => {
       if(i === 0) {
-        return `"dc1"`;
+        return `"${env('CONSUL_DATACENTER_LOCAL', 'dc1')}"`;
       }
       return `
         "${fake.address.countryCode().toLowerCase()}_${ i % 2 ? "west" : "east"}-${i}"

ui/packages/consul-ui/tests/acceptance/dc/error.feature

@@ -23,8 +23,6 @@ Feature: dc / error: Recovering from a dc 500 error
     Then the url should be /dc-500/services
     And the title should be "Consul"
     Then I see status on the error like "500"
-  # FIXME
-  @ignore
   Scenario: Clicking the back to root button
     Given the url "/v1/internal/ui/services" responds with a 200 status
     When I click home

ui/packages/consul-ui/tests/acceptance/dc/services/error.feature

@@ -1,6 +1,4 @@
 @setupApplicationTest
-# FIXME
-@ignore
 Feature: dc / services / error
   Scenario: Arriving at the service page that doesn't exist
     Given 2 datacenter models from yaml
@@ -8,11 +6,12 @@ Feature: dc / services / error
     - dc-1
     - dc-2
     ---
+    Given the url "/v1/internal/ui/services" responds with a 500 status
     When I visit the services page for yaml
     ---
-      dc: 404-datacenter
+      dc: non-existent-datacenter
     ---
-    Then I see status on the error like "404"
+    Then I see status on the error like "500"
   @notNamespaceable
   Scenario: Arriving at the service page
     Given 2 datacenter models from yaml

ui/packages/consul-ui/tests/steps/doubles/model.js

@@ -7,11 +7,17 @@ export default function(scenario, create, set, win = window, doc = document) {
       return create(number, model);
     })
     .given(['$number $model model[s]? with the value "$value"'], function(number, model, value) {
+      if (model === 'dc') {
+        doc.cookie = `CONSUL_DATACENTER_LOCAL=${value}`;
+      }
       return create(number, model, value);
     })
     .given(
       ['$number $model model[s]? from yaml\n$yaml', '$number $model model[s]? from json\n$json'],
       function(number, model, data) {
+        if (model === 'dc') {
+          doc.cookie = `CONSUL_DATACENTER_LOCAL=${data[0]}`;
+        }
         return create(number, model, data);
       }
     )