From f2969ef1b67192773cd4df5c3d54cbdd0369d2dd Mon Sep 17 00:00:00 2001
From: Sukeerth Vegaraju <ssvegaraju@yahoo.co.in>
Date: Thu, 21 Jul 2022 11:34:33 -0700
Subject: [PATCH] fix: update provisioned concurrency to address cold starts
 (#661)

---
 lib/cdk-infra-stack.ts   | 13 ++++++-------
 lib/javaHapiValidator.ts |  5 ++++-
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/lib/cdk-infra-stack.ts b/lib/cdk-infra-stack.ts
index 94a50901..5e7ccb86 100644
--- a/lib/cdk-infra-stack.ts
+++ b/lib/cdk-infra-stack.ts
@@ -537,6 +537,9 @@ export default class FhirWorksStack extends Stack {
             description: 'FHIR API Server',
             entry: path.join(__dirname, '../src/index.ts'),
             handler: 'handler',
+            currentVersionOptions: {
+                provisionedConcurrentExecutions: 5,
+            },
             bundling: {
                 ...defaultLambdaBundlingOptions,
                 commandHooks: {
@@ -558,17 +561,12 @@ export default class FhirWorksStack extends Stack {
                 },
             },
             runtime: Runtime.NODEJS_14_X,
-            currentVersionOptions: {
-                provisionedConcurrentExecutions: 5,
-            },
             environment: {
                 ...lambdaDefaultEnvVars,
                 EXPORT_STATE_MACHINE_ARN: bulkExportStateMachine.bulkExportStateMachine.stateMachineArn,
                 PATIENT_COMPARTMENT_V3,
                 PATIENT_COMPARTMENT_V4,
-                VALIDATOR_LAMBDA_ALIAS: props!.useHapiValidator
-                    ? this.javaHapiValidator!.hapiValidatorLambda.functionArn
-                    : '',
+                VALIDATOR_LAMBDA_ALIAS: props!.useHapiValidator ? this.javaHapiValidator!.alias.functionArn : '',
             },
             role: new Role(this, 'fhirServerLambdaRole', {
                 assumedBy: new ServicePrincipal('lambda.amazonaws.com'),
@@ -666,10 +664,11 @@ export default class FhirWorksStack extends Stack {
                 new PolicyStatement({
                     effect: Effect.ALLOW,
                     actions: ['lambda:InvokeFunction'],
-                    resources: [this.javaHapiValidator!.hapiValidatorLambda.functionArn],
+                    resources: [this.javaHapiValidator!.alias.functionArn],
                 }),
             );
         }
+        fhirServerLambda.currentVersion.addAlias(`fhir-server-lambda-${props!.stage}`);
 
         const apiGatewayApiKey = apiGatewayRestApi.addApiKey('developerApiKey', {
             description: 'Key for developer access to the FHIR Api',
diff --git a/lib/javaHapiValidator.ts b/lib/javaHapiValidator.ts
index 7225ca47..93f8fdf4 100644
--- a/lib/javaHapiValidator.ts
+++ b/lib/javaHapiValidator.ts
@@ -1,5 +1,5 @@
 import { Duration, Stack, StackProps } from 'aws-cdk-lib';
-import { Code, Function, Runtime, Tracing } from 'aws-cdk-lib/aws-lambda';
+import { Alias, Code, Function, Runtime, Tracing } from 'aws-cdk-lib/aws-lambda';
 import { RetentionDays } from 'aws-cdk-lib/aws-logs';
 import { Construct } from 'constructs';
 import * as path from 'path';
@@ -13,6 +13,8 @@ export interface JavaHapiValidatorProps extends StackProps {
 export default class JavaHapiValidator extends Stack {
     hapiValidatorLambda: Function;
 
+    alias: Alias;
+
     constructor(scope: Construct, id: string, props: JavaHapiValidatorProps) {
         super(scope, id, props);
 
@@ -34,5 +36,6 @@ export default class JavaHapiValidator extends Stack {
                 FHIR_VERSION: props.fhirVersion,
             },
         });
+        this.alias = this.hapiValidatorLambda.currentVersion.addAlias(`fhir-service-validator-lambda-${props.stage}`);
     }
 }