Merge pull request #23 from localstack-samples/hotreloading

Author: lukqw

Makefile

@@ -16,6 +16,9 @@ install:
 build:
 		yarn && yarn build:backend;
 
+hotreload:
+		yarn && yarn hotreload:backend;
+
 bootstrap:
 		yarn cdklocal bootstrap;
 
@@ -34,6 +37,9 @@ prepare-frontend-local:
 build-frontend:
 		yarn build:frontend
 
+start-frontend:
+		yarn start:frontend
+
 bootstrap-frontend:
 		yarn cdklocal bootstrap --app="node dist/aws-sdk-js-notes-app-frontend.js";
 
@@ -54,4 +60,12 @@ ready:
 logs:
 		@localstack logs > logs.txt
 
+setup-challenge:
+		yarn install
+		make build
+		make bootstrap
+		IS_LOCAL_DEV=true make deploy
+		make prepare-frontend-local
+		make hotreload
+
 .PHONY: usage install run start stop ready logs

package.json

@@ -9,6 +9,7 @@
     "cdk": "cd packages/infra && yarn cdk",
     "cdklocal": "cd packages/infra && yarn cdklocal",
     "build:backend": "cd packages/backend && yarn build",
+    "hotreload:backend": "cd packages/backend && yarn hotreload",
     "prepare:frontend": "node packages/scripts/populate-frontend-config.js",
     "prepare:frontend-local": "node packages/scripts/populate-frontend-config.js --local",
     "build:frontend": "cd packages/frontend && yarn build",

packages/backend/package.json

@@ -5,11 +5,13 @@
   "description": "Backend for notes app created using modular AWS SDK for JavaScript",
   "dependencies": {
     "@aws-sdk/client-dynamodb": "3.245.0",
-    "@aws-sdk/util-dynamodb": "3.245.0"
+    "@aws-sdk/util-dynamodb": "3.245.0",
+    "nodemon": "^3.1.7"
   },
   "scripts": {
     "build": "tsc --noEmit && node build.js",
     "build:backend": "cd .. && yarn build:backend",
+    "hotreload": "nodemon --watch src --ext '*' --exec 'node build.js'",
     "cdk": "cd .. && yarn cdk"
   },
   "keywords": [

packages/infra/cdk/notes-api.ts

@@ -1,4 +1,8 @@
-import { aws_dynamodb as dynamodb, aws_lambda as lambda } from "aws-cdk-lib";
+import {
+  aws_dynamodb as dynamodb,
+  aws_lambda as lambda,
+  aws_s3 as s3,
+} from "aws-cdk-lib";
 import { Construct } from "constructs";
 
 export interface NotesApiProps {
@@ -17,11 +21,19 @@ export class NotesApi extends Construct {
 
     const { table, grantActions } = props;
 
+    const isLocalDev = ["true", true].includes(process.env.IS_LOCAL_DEV);
+
+    const codeConfig = isLocalDev
+      ? lambda.Code.fromBucket(
+          s3.Bucket.fromBucketName(this, "hot-reload", "hot-reload"),
+          `${__dirname}/../../backend/dist/${id}`
+        )
+      : lambda.Code.fromAsset(`../backend/dist/${id}`);
+
     this.handler = new lambda.Function(this, "handler", {
       runtime: lambda.Runtime.NODEJS_18_X,
       handler: "app.handler",
-      // ToDo: find a better way to pass lambda code
-      code: lambda.Code.fromAsset(`../backend/dist/${id}`),
+      code: codeConfig,
       environment: {
         NOTES_TABLE_NAME: table.tableName,
       },