feat(batch): Importing a JobDefinition from name using `fromJobDefi…

…nitionName` (#10448)

Add `fromJobDefinitionName` for `JobDefinition` construct. Ref: https://stackoverflow.com/a/55031183

closes #7172 

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-batch/README.md

@@ -242,10 +242,27 @@ new batch.JobDefinition(stack, 'batch-job-def-from-local', {
 
 ### Importing an existing Job Definition
 
-To import an existing batch job definition, call `JobDefinition.fromJobDefinitionArn()`.
+#### From ARN
+
+To import an existing batch job definition from its ARN, call `JobDefinition.fromJobDefinitionArn()`.
 
 Below is an example:
 
 ```ts
 const job = batch.JobDefinition.fromJobDefinitionArn(this, 'imported-job-definition', 'arn:aws:batch:us-east-1:555555555555:job-definition/my-job-definition');
 ```
+
+#### From Name
+
+To import an existing batch job definition from its name, call `JobDefinition.fromJobDefinitionName()`.
+If name is specified without a revision then the latest active revision is used.
+
+Below is an example:
+
+```ts
+// Without revision
+const job = batch.JobDefinition.fromJobDefinitionName(this, 'imported-job-definition', 'my-job-definition');
+
+// With revision
+const job = batch.JobDefinition.fromJobDefinitionName(this, 'imported-job-definition', 'my-job-definition:3');
+```

packages/@aws-cdk/aws-batch/lib/job-definition.ts

@@ -269,6 +269,31 @@ export class JobDefinition extends Resource implements IJobDefinition {
     return new Import(scope, id);
   }
 
+  /**
+   * Imports an existing batch job definition by its name.
+   * If name is specified without a revision then the latest active revision is used.
+   *
+   * @param scope
+   * @param id
+   * @param jobDefinitionName
+   */
+  public static fromJobDefinitionName(scope: Construct, id: string, jobDefinitionName: string): IJobDefinition {
+    const stack = Stack.of(scope);
+    const jobDefArn = stack.formatArn({
+      service: 'batch',
+      resource: 'job-definition',
+      sep: '/',
+      resourceName: jobDefinitionName,
+    });
+
+    class Import extends Resource implements IJobDefinition {
+      public readonly jobDefinitionArn = jobDefArn;
+      public readonly jobDefinitionName = jobDefinitionName;
+    }
+
+    return new Import(scope, id);
+  }
+
   public readonly jobDefinitionArn: string;
   public readonly jobDefinitionName: string;
   private readonly imageConfig: JobDefinitionImageConfig;

packages/@aws-cdk/aws-batch/test/job-definition.test.ts

@@ -200,4 +200,14 @@ describe('Batch Job Definition', () => {
     expect(importedJob.jobDefinitionName).toEqual('job-def-name:1');
     expect(importedJob.jobDefinitionArn).toEqual('arn:aws:batch:us-east-1:123456789012:job-definition/job-def-name:1');
   });
+
+  test('can be imported from a name', () => {
+    // WHEN
+    const importedJob = batch.JobDefinition.fromJobDefinitionName(stack, 'job-def-clone', 'job-def-name');
+
+    // THEN
+    expect(importedJob.jobDefinitionName).toEqual('job-def-name');
+    expect(importedJob.jobDefinitionArn)
+      .toEqual('arn:${Token[AWS.Partition.3]}:batch:${Token[AWS.Region.4]}:${Token[AWS.AccountId.0]}:job-definition/job-def-name');
+  });
 });