[YUNIKORN-357] Show REST API availability (apache#46)

If the scheduler core is not up or the port of the REST API is not
reachable an empty page was shown. Now we show an error message with the
reason that there is no data to show.

Fixes: apache#46

src/app/app-routing.module.ts

@@ -23,6 +23,7 @@ import { DashboardComponent } from './components/dashboard/dashboard.component';
 import { QueuesViewComponent } from './components/queues-view/queues-view.component';
 import { AppsViewComponent } from './components/apps-view/apps-view.component';
 import { NodesViewComponent } from './components/nodes-view/nodes-view.component';
+import { ErrorViewComponent } from './components/error-view/error-view.component';
 
 const appRoutes: Routes = [
   {
@@ -45,6 +46,11 @@ const appRoutes: Routes = [
     component: NodesViewComponent,
     data: { breadcrumb: 'Nodes' }
   },
+  {
+    path: 'error',
+    component: ErrorViewComponent,
+    data: { breadcrumb: 'Error' }
+  },
   {
     path: '',
     pathMatch: 'full',

src/app/app.module.ts

@@ -19,7 +19,7 @@
 import { NgModule, APP_INITIALIZER } from '@angular/core';
 import { BrowserModule } from '@angular/platform-browser';
 import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
-import { HttpClientModule } from '@angular/common/http';
+import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
 import { NgxSpinnerModule } from 'ngx-spinner';
 import { FormsModule } from '@angular/forms';
 import {
@@ -40,6 +40,7 @@ import {
 
 import { AppRoutingModule } from './app-routing.module';
 import { envConfigFactory, EnvconfigService } from './services/envconfig/envconfig.service';
+import { ApiErrorInterceptor } from './interceptors/api-error/api-error.interceptor';
 import { AppComponent } from './app.component';
 import { DashboardComponent } from './components/dashboard/dashboard.component';
 import { QueuesViewComponent } from './components/queues-view/queues-view.component';
@@ -52,6 +53,7 @@ import { ContainerHistoryComponent } from './components/container-history/contai
 import { QueueRackComponent } from './components/queue-rack/queue-rack.component';
 import { AppsViewComponent } from './components/apps-view/apps-view.component';
 import { NodesViewComponent } from './components/nodes-view/nodes-view.component';
+import { ErrorViewComponent } from './components/error-view/error-view.component';
 
 @NgModule({
   declarations: [
@@ -66,7 +68,8 @@ import { NodesViewComponent } from './components/nodes-view/nodes-view.component
     ContainerHistoryComponent,
     QueueRackComponent,
     AppsViewComponent,
-    NodesViewComponent
+    NodesViewComponent,
+    ErrorViewComponent
   ],
   imports: [
     BrowserModule,
@@ -95,6 +98,11 @@ import { NodesViewComponent } from './components/nodes-view/nodes-view.component
       useFactory: envConfigFactory,
       deps: [EnvconfigService],
       multi: true
+    },
+    {
+      provide: HTTP_INTERCEPTORS,
+      useClass: ApiErrorInterceptor,
+      multi: true
     }
   ],
   bootstrap: [AppComponent]

src/app/components/dashboard/dashboard.component.html

@@ -19,24 +19,24 @@
 <mat-card *ngIf="clusterInfo">
   <div class="flex-grid">
     <div class="flex-primary">
-      <div class="text-uppercase hwx-light">Name</div>
-      <div class="info-value hwx-strong">{{ clusterInfo.clusterName }}</div>
+      <div class="text-uppercase light-text">Name</div>
+      <div class="info-value strong-text">{{ clusterInfo.clusterName }}</div>
     </div>
     <div class="flex-primary">
-      <div class="text-uppercase hwx-light">Status</div>
-      <div class="info-value hwx-strong">{{ clusterInfo.clusterStatus }}</div>
+      <div class="text-uppercase light-text">Status</div>
+      <div class="info-value strong-text">{{ clusterInfo.clusterStatus }}</div>
     </div>
     <div class="flex-primary">
-      <div class="text-uppercase hwx-light">Nodes</div>
-      <div class="info-value hwx-strong">{{ clusterInfo.activeNodes }}</div>
+      <div class="text-uppercase light-text">Nodes</div>
+      <div class="info-value strong-text">{{ clusterInfo.activeNodes }}</div>
     </div>
     <div class="flex-primary">
-      <div class="text-uppercase hwx-light">Applications</div>
-      <div class="info-value hwx-strong">{{ clusterInfo.runningApplications }}</div>
+      <div class="text-uppercase light-text">Applications</div>
+      <div class="info-value strong-text">{{ clusterInfo.runningApplications }}</div>
     </div>
     <div class="flex-primary">
-      <div class="text-uppercase hwx-light">Containers</div>
-      <div class="info-value hwx-strong">{{ clusterInfo.runningContainers }}</div>
+      <div class="text-uppercase light-text">Containers</div>
+      <div class="info-value strong-text">{{ clusterInfo.runningContainers }}</div>
     </div>
   </div>
 </mat-card>

src/app/components/error-view/error-view.component.html

@@ -0,0 +1,21 @@
+<!--
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ -->
+
+<mat-card class="error-view">
+  Oops, Something went wrong. YuniKorn scheduler is not accessible.
+</mat-card>

src/app/components/error-view/error-view.component.scss

@@ -0,0 +1,22 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+.error-view {
+  color: #cb0100;
+  text-align: center;
+}

src/app/components/error-view/error-view.component.spec.ts

@@ -0,0 +1,45 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { async, ComponentFixture, TestBed } from '@angular/core/testing';
+import { configureTestSuite } from 'ng-bullet';
+import { MatCardModule } from '@angular/material';
+
+import { ErrorViewComponent } from './error-view.component';
+
+describe('ErrorViewComponent', () => {
+  let component: ErrorViewComponent;
+  let fixture: ComponentFixture<ErrorViewComponent>;
+
+  configureTestSuite(() => {
+    TestBed.configureTestingModule({
+      imports: [MatCardModule],
+      declarations: [ErrorViewComponent]
+    });
+  });
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(ErrorViewComponent);
+    component = fixture.componentInstance;
+    fixture.detectChanges();
+  });
+
+  it('should create the component', () => {
+    expect(component).toBeTruthy();
+  });
+});

src/app/components/error-view/error-view.component.ts

@@ -0,0 +1,33 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Component, OnInit } from '@angular/core';
+
+@Component({
+  selector: 'app-error-view',
+  templateUrl: './error-view.component.html',
+  styleUrls: ['./error-view.component.scss']
+})
+export class ErrorViewComponent implements OnInit {
+
+  constructor() { }
+
+  ngOnInit() {
+  }
+
+}

src/app/interceptors/api-error/api-error.interceptor.spec.ts

@@ -0,0 +1,42 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { TestBed } from '@angular/core/testing';
+import { configureTestSuite } from 'ng-bullet';
+import { RouterTestingModule } from '@angular/router/testing';
+
+import { ApiErrorInterceptor } from './api-error.interceptor';
+
+describe('ApiErrorInterceptor', () => {
+  let interceptor: ApiErrorInterceptor;
+
+  configureTestSuite(() => {
+    TestBed.configureTestingModule({
+      imports: [RouterTestingModule],
+      providers: [ApiErrorInterceptor]
+    });
+  });
+
+  beforeEach(() => {
+    interceptor = TestBed.get(ApiErrorInterceptor);
+  });
+
+  it('should create the interceptor', () => {
+    expect(interceptor).toBeTruthy();
+  });
+});

src/app/interceptors/api-error/api-error.interceptor.ts

@@ -0,0 +1,43 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { Injectable } from '@angular/core';
+import { Router } from '@angular/router';
+import { Observable, throwError } from 'rxjs';
+import { catchError } from 'rxjs/operators';
+import {
+  HttpEvent,
+  HttpInterceptor,
+  HttpHandler,
+  HttpRequest,
+  HttpErrorResponse
+} from '@angular/common/http';
+
+@Injectable()
+export class ApiErrorInterceptor implements HttpInterceptor {
+  constructor(private router: Router) {}
+
+  intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
+    return next.handle(request).pipe(catchError(this.handleApiError.bind(this)));
+  }
+
+  handleApiError(error: HttpErrorResponse) {
+    this.router.navigate(['/error']);
+    return throwError(error);
+  }
+}