fix: Handle case where no ECS tasks are returned (#146)

Author: niallthomson

plugins/ecs/backend/src/service/DefaultAmazonEcsService.test.ts

@@ -328,6 +328,65 @@ describe('DefaultAmazonEcsService', () => {
 
       expect(mockResourceLocator.getResourceArns).toHaveBeenCalledTimes(0);
     });
+
+    it('handles empty tasks', async () => {
+      const cluster1 = mockEcsCluster('cluster1');
+      const service1 = mockEcsService('service1', 'cluster1', 1, 1, 0);
+
+      ecsMock
+        .on(DescribeClustersCommand, {
+          clusters: ['cluster1'],
+        })
+        .resolves({
+          clusters: [cluster1],
+        });
+
+      ecsMock
+        .on(DescribeServicesCommand, {
+          cluster: 'cluster1',
+          // services: ['service1'],
+        })
+        .resolves({
+          services: [service1],
+        });
+
+      ecsMock
+        .on(ListTasksCommand, {
+          cluster: 'cluster1',
+          serviceName: 'service1',
+        })
+        .resolves({
+          taskArns: [],
+        });
+
+      const service = await configureProvider(
+        {},
+        {
+          metadata: {
+            annotations: {
+              [AWS_ECS_SERVICE_ARN_ANNOTATION]:
+                'arn:aws:ecs:us-west-2:1234567890:service/cluster1/service1',
+            },
+          },
+        },
+      );
+
+      const response = await service.getServicesByEntity({ entityRef });
+
+      await expect(response).toMatchObject({
+        clusters: [
+          {
+            cluster: cluster1,
+            services: [
+              {
+                service: service1,
+                tasks: [],
+              },
+            ],
+          },
+        ],
+      });
+    });
   });
 
   it('throws on missing annotation', async () => {

plugins/ecs/backend/src/service/DefaultAmazonEcsService.ts

@@ -18,6 +18,7 @@ import {
   DescribeClustersCommand,
   ListTasksCommand,
   DescribeTasksCommand,
+  Task,
 } from '@aws-sdk/client-ecs';
 import { parse } from '@aws-sdk/util-arn-parser';
 import { CatalogApi } from '@backstage/catalog-client';
@@ -205,16 +206,22 @@ export class DefaultAmazonEcsService implements AmazonECSService {
             }),
           );
 
-          const describeTasksResp = await client.send(
-            new DescribeTasksCommand({
-              cluster,
-              tasks: listTasksResp.taskArns,
-            }),
-          );
+          let tasks: Task[] = [];
+
+          if (listTasksResp.taskArns?.length) {
+            const describeTasksResp = await client.send(
+              new DescribeTasksCommand({
+                cluster,
+                tasks: listTasksResp.taskArns,
+              }),
+            );
+
+            tasks = describeTasksResp.tasks || [];
+          }
 
           serviceResponseObjects.push({
             service: serviceResp,
-            tasks: describeTasksResp.tasks!,
+            tasks,
           });
         }
       }

plugins/ecs/frontend/src/components/EcsServices/EcsServices.tsx

@@ -230,7 +230,11 @@ const ClusterSummary = ({ cluster }: { cluster: ClusterResponse }) => {
         spacing={0}
       >
         <Grid item>
-          <StatusOK>{runningTasks} running tasks</StatusOK>
+          {runningTasks > 0 ? (
+            <StatusOK>{runningTasks} running tasks</StatusOK>
+          ) : (
+            <StatusOK>No running tasks</StatusOK>
+          )}
         </Grid>
         <Grid item>
           {pendingTasks > 0 ? (
@@ -279,7 +283,11 @@ const ServiceSummary = ({ service }: { service: Service }) => {
         spacing={0}
       >
         <Grid item>
-          <StatusOK>{service.runningCount} running tasks</StatusOK>
+          {service.runningCount! > 0 ? (
+            <StatusOK>{service.runningCount} running tasks</StatusOK>
+          ) : (
+            <StatusOK>No running tasks</StatusOK>
+          )}
         </Grid>
         <Grid item>
           {service.pendingCount! > 0 ? (