introduce layer dep

lib/workload/stateless/postgres_manager/deploy/construct/layer/node_module.Dockerfile

@@ -0,0 +1,16 @@
+# This image will generate the node_modules needed for lambda and let
+# the layer reference the output from this image
+
+FROM public.ecr.aws/docker/library/node:20-alpine
+
+WORKDIR /home/node/app
+
+COPY package.json package.json
+COPY yarn.lock yarn.lock
+RUN yarn install --immutable
+
+# making nodejs folder where as guided in the AWS lambda layer docs
+RUN mkdir -p output/nodejs
+
+# copy node_modules to that folder
+RUN cp -r node_modules output/nodejs

lib/workload/stateless/postgres_manager/deploy/postgres-manager-stack.ts

@@ -39,11 +39,21 @@ export class PostgresManagerStack extends Stack {
       props.clusterResourceIdParameterName
     );
 
+    const dependencyLayer = new lambda.LayerVersion(this, 'DependenciesLayer', {
+      code: lambda.Code.fromDockerBuild(__dirname + '/../', {
+        cacheDisabled: true,
+        file: 'deploy/construct/layer/node_module.Dockerfile',
+        imagePath: 'home/node/app/output',
+      }),
+      compatibleArchitectures: [lambda.Architecture.ARM_64],
+      compatibleRuntimes: [lambda.Runtime.NODEJS_20_X],
+    });
+
     const runtimeDependencies = Object.keys(package_json.dependencies);
     const rdsLambdaProps: nodejs.NodejsFunctionProps = {
-      bundling: { nodeModules: runtimeDependencies },
+      layers: [dependencyLayer],
+      bundling: { externalModules: runtimeDependencies },
       timeout: Duration.minutes(5),
-      depsLockFilePath: __dirname + '/../yarn.lock',
       handler: 'handler',
       runtime: lambda.Runtime.NODEJS_20_X,
       architecture: lambda.Architecture.ARM_64,
@@ -101,9 +111,7 @@ export class PostgresManagerStack extends Stack {
         new iam.PolicyStatement({
           actions: ['secretsmanager:CreateSecret', 'secretsmanager:TagResource'],
           effect: iam.Effect.ALLOW,
-          resources: [
-            `arn:aws:secretsmanager:ap-southeast-2:*:secret:*`,
-          ],
+          resources: [`arn:aws:secretsmanager:ap-southeast-2:*:secret:*`],
         }),
         new iam.PolicyStatement({
           actions: ['secretsmanager:GetRandomPassword'],