Add option to configure custom favicon

closes #903

Author: Mikhail Kuznetcov

spring-boot-admin-docs/src/main/asciidoc/customizing.adoc

@@ -95,3 +95,15 @@ Either you just add the image to your jar-file in `/META-INF/spring-boot-admin-s
 or you must ensure yourself that the image gets served correctly (e.g. by registering your own `ResourceHandler`)
 
 - **spring.boot.admin.ui.title**: Use this option to customize the browsers window title.
+
+=== Customizing Page Favicon ===
+You can show custom browser favicon by using following configuration properties:
+
+- **spring.boot.admin.ui.faviconBase**: Sets default icon, that is shown when all services are up.
+
+- **spring.boot.admin.ui.faviconDanger**: Sets alerting icon that is shown when 1 or more services are down.
+
+In first place you need get the icon of min 32x32 pixels in `.png` of `.ico` format - you can use one of online favicon generators for this).
+You should place the file into the assets folder of the ui subproject `/META-INF/spring-boot-admin-server-ui/assets/`. 
+Then property should include path from root of the `/META-INF/spring-boot-admin-server-ui/` for example `assets/img/company-favicon.png`.
+

spring-boot-admin-docs/src/main/asciidoc/server.adoc

@@ -63,6 +63,14 @@ In addition when the reverse proxy terminates the https connection, it may be ne
 | Page-Title to be shown.
 | `"Spring Boot Admin"`
 
+| spring.boot.admin.ui.faviconBase
+| Custom favicon when all services are up
+| `"assets/img/favicon.png"`
+
+| spring.boot.admin.ui.faviconDanger
+| Custom favicon when one or more services is down
+| `"assets/img/favicon-danger.png"`
+
 |===
 
 include::server-discovery.adoc[]

spring-boot-admin-server-ui/src/main/frontend/views/applications/handle.vue

@@ -27,6 +27,10 @@
 
 <script>
   export default {
+     data: () => ({
+      faviconBase: 'assets/img/favicon.png',
+      faviconDanger: 'assets/img/favicon-danger.png',
+    }),
     props: {
       applications: {
         type: Array,
@@ -44,6 +48,16 @@
         }, 0);
       }
     },
+    created() {
+      if (global.SBA && global.SBA.uiSettings) {
+        if (global.SBA.uiSettings.favicon) {
+          this.faviconBase = global.SBA.uiSettings.faviconBase
+        }
+        if (global.SBA.uiSettings.faviconDanger) {
+          this.faviconDanger = global.SBA.uiSettings.faviconDanger
+        }
+      }
+    },
     watch: {
       downCount(newVal, oldVal) {
         if ((newVal === 0) !== (oldVal === 0)) {
@@ -53,7 +67,7 @@
     },
     methods: {
       updateFavicon(up) {
-        document.querySelector('link[rel*="icon"]').href = up ? 'assets/img/favicon.png' : 'assets/img/favicon-danger.png';
+        document.querySelector('link[rel*="icon"]').href = up ? this.faviconBase : this.faviconDanger;
       }
     }
   };

spring-boot-admin-server-ui/src/main/java/de/codecentric/boot/admin/server/ui/config/AdminServerUiAutoConfiguration.java

@@ -69,6 +69,8 @@ public UiController homeUiController() throws IOException {
             null ? this.uiProperties.getPublicUrl() : this.adminServerProperties.getContextPath(),
             this.uiProperties.getTitle(),
             this.uiProperties.getBrand(),
+            this.uiProperties.getFaviconBase(),
+            this.uiProperties.getFaviconDanger(),
             this.uiExtensions(),
             !this.applicationContext.getBeansOfType(NotificationFilterController.class).isEmpty()
         );

spring-boot-admin-server-ui/src/main/java/de/codecentric/boot/admin/server/ui/config/AdminServerUiProperties.java

@@ -45,6 +45,16 @@ public class AdminServerUiProperties {
      */
     private String templateLocation = CLASSPATH_RESOURCE_LOCATIONS[0];
 
+    /**
+     * Custom favicon. When all services are up
+     */
+    private String faviconBase = null;
+
+    /**
+     * Custom favicon. When one or more services is down
+     */
+    private String faviconDanger = null;
+
     /**
      * Page-Title to be shown.
      */

spring-boot-admin-server-ui/src/main/java/de/codecentric/boot/admin/server/ui/web/UiController.java

@@ -44,12 +44,16 @@ public class UiController {
     public UiController(String publicUrl,
                         String title,
                         String brand,
+                        String faviconBase,
+                        String faviconDanger,
                         List<UiExtension> uiExtensions,
                         boolean notificationFilterEnabled) {
         this.publicUrl = publicUrl;
         this.uiSettings = new HashMap<>();
         this.uiSettings.put("title", title);
         this.uiSettings.put("brand", brand);
+        this.uiSettings.put("faviconBase", faviconBase);
+        this.uiSettings.put("faviconDanger", faviconDanger);
         this.uiSettings.put("notificationFilterEnabled", notificationFilterEnabled);
         this.cssExtensions = uiExtensions.stream()
                                          .filter(e -> e.getResourcePath().endsWith(".css"))

spring-boot-admin-server-ui/src/test/java/de/codecentric/boot/admin/server/ui/web/UiControllerTest.java

@@ -71,7 +71,7 @@ public void should_use_scheme_host_and_path_from_public_url() throws Exception {
     }
 
     private MockMvc setupController(String publicUrl) {
-        return MockMvcBuilders.standaloneSetup(new UiController(publicUrl, "", "", Collections.emptyList(), false))
+        return MockMvcBuilders.standaloneSetup(new UiController(publicUrl, "", "", "", "", Collections.emptyList(), false))
                               .setCustomHandlerMapping(() -> new AdminControllerHandlerMapping(""))
                               .build();
     }