Keep log stream open when running a container with KubernetesContainerRunner

Signed-off-by: ovalice <31350208+ovalice@users.noreply.github.com>

.changeset/wise-moons-begin.md

@@ -0,0 +1,5 @@
+---
+'@backstage/backend-common': patch
+---
+
+KubernetesContainerRunner.runContainer no longer closes the `logStream` is receives as input.

packages/backend-common/src/util/KubernetesContainerRunner.test.ts

@@ -187,6 +187,25 @@ describeIfKubernetes('KubernetesContainerRunner', () => {
     );
   });
 
+  it('should not close the original log stream', async () => {
+    const options: KubernetesContainerRunnerOptions = {
+      kubeConfig,
+      name,
+      namespace: 'default',
+    };
+    const containerRunner = new KubernetesContainerRunner(options);
+    const logStream = new PassThrough();
+    const runOptions: RunContainerOptions = {
+      imageName: 'alpine',
+      args: ['echo', 'hello world'],
+      logStream,
+    };
+
+    await containerRunner.runContainer(runOptions);
+
+    expect(logStream.closed).toBe(false);
+  });
+
   describe('with namespace test', () => {
     let api: CoreV1Api;
     let authApi: RbacAuthorizationV1Api;

packages/backend-common/src/util/KubernetesContainerRunner.ts

@@ -132,12 +132,17 @@ export class KubernetesContainerRunner implements ContainerRunner {
       imageName,
       command,
       args,
-      logStream = new PassThrough(),
+      logStream,
       mountDirs = {},
       workingDir,
       envVars = {},
     } = options;
 
+    const containerLogStream = new PassThrough();
+    if (logStream) {
+      containerLogStream.pipe(logStream, { end: false });
+    }
+
     const commandArr = typeof command === 'string' ? [command] : command;
 
     const volumeMounts: V1VolumeMount[] = [];
@@ -209,7 +214,7 @@ export class KubernetesContainerRunner implements ContainerRunner {
       },
     };
 
-    await this.runJob(jobSpec, taskId, logStream);
+    await this.runJob(jobSpec, taskId, containerLogStream);
   }
 
   private handleError(err: any, errorCallback: (reason: any) => void) {