locals

examples/simple/stacks/simple.ts

@@ -83,8 +83,12 @@ class MyBucketStack extends tsk.Stack {
       region: aModule.getString("region")
     });
 
+    const aLocal = new tsk.Local(this, 'local_val', {
+      expression: bucket.arn
+    });
+
     new tsk.Output(this, 'bucket_arn', {
-      value: bucket.arn,
+      value: aLocal.value,
       description: "A bucket arn"
     })
 

packages/@terrastack/core/lib/index.ts

@@ -7,4 +7,5 @@ export * from './backends';
 export * from './remote-state';
 export * from './output';
 export * from './variable';
-export * from './module';
+export * from './module';
+export * from './local';

packages/@terrastack/core/lib/local.ts

@@ -0,0 +1,40 @@
+import { ResourceObject, TerraformSchemaType } from './resource-object';
+import { Construct } from 'constructs';
+
+export class Local extends ResourceObject {
+    value: any;
+
+    constructor(scope: Construct, ns: string, options: LocalProps) {
+        super(scope, ns, { ...options }, {
+            name: "local",
+            schemaType: TerraformSchemaType.LOCALS,
+            providerVersion: "1.0",
+            providerName: "terraform",
+            rawSchema: ""
+        });
+
+        this.value = `\$\{local.${this._name}\}`
+    }
+
+    public get stringValue(): string {
+        return this.value;
+    }
+
+    public get numberValue(): number {
+        return this.value;
+    }
+
+    /**
+     * Renders the object to Terraform config.
+     * @internal
+     */
+    public _render(): any {
+        const obj: {[k: string]: any} = {};
+        obj[this._name] = this.tfProperties.expression
+        return obj;
+    }
+}
+
+export interface LocalProps {
+    readonly expression: any;
+}

packages/@terrastack/core/lib/resource-object.ts

@@ -41,7 +41,8 @@ export enum TerraformSchemaType {
   TERRAFORM = 'terraform',
   OUTPUT = 'output',
   VARIABLE = 'variable',
-  MODULE = 'module'
+  MODULE = 'module',
+  LOCALS = 'locals'
 }
 
 export interface TerraformMetadata {

packages/@terrastack/core/lib/stack.ts

@@ -70,7 +70,8 @@ export class Stack extends Construct {
         case TerraformSchemaType.TERRAFORM:
         case TerraformSchemaType.OUTPUT:
         case TerraformSchemaType.VARIABLE:
-        case TerraformSchemaType.MODULE: {
+        case TerraformSchemaType.MODULE:
+        case TerraformSchemaType.LOCALS: {
           const manifest = removeEmpty(resolve(this, resource._render()));
           const merged = {...doc[type], ...manifest}
           doc[type] = merged