Add Kotlin Lambda (CDK) example

.github/workflows/pre-release.yml

@@ -80,6 +80,13 @@ jobs:
           arguments: check
           build-root-directory: kotlin/hello-world-lambda
 
+      # CDK projects are a hybrid of TypeScript CDK stack + platform-specific handler code; the top-level npm CDK build
+      # is responsible for verifying the language-specific handler cod. They are also not a part of the TypeScript
+      # examples workspace, so we test them separately here.
+      - name: Test kotlin/hello-world-lambda-cdk
+        if: github.event.inputs.sdkTypescriptVersion != '' && github.event.inputs.sdkJavaVersion != ''
+        run: npm --prefix kotlin/hello-world-lambda-cdk run verify
+
       - name: Create Pull Request
         uses: peter-evans/create-pull-request@v5
         with:

.github/workflows/release.yml

@@ -33,4 +33,5 @@ jobs:
             java-hello-world-http.zip
             java-hello-world-lambda.zip
             kotlin-hello-world-http.zip
-            kotlin-hello-world-lambda.zip
+            kotlin-hello-world-lambda.zip
+            kotlin-hello-world-lambda-cdk.zip

.github/workflows/test.yml

@@ -45,6 +45,14 @@ jobs:
         with:
           arguments: check
           build-root-directory: kotlin/hello-world-lambda
+
+      # CDK projects are a hybrid of TypeScript CDK stack + platform-specific handler code; the top-level npm CDK build
+      # is responsible for verifying the language-specific handler cod. They are also not a part of the TypeScript
+      # examples workspace, so we test them separately here.
+      - name: Test kotlin/hello-world-lambda-cdk
+        if: github.event.inputs.sdkTypescriptVersion != '' && github.event.inputs.sdkJavaVersion != ''
+        run: npm --prefix kotlin/hello-world-lambda-cdk run verify
+
   build-ts:
     # prevent from running on forks
     if: github.repository_owner == 'restatedev'

kotlin/hello-world-lambda-cdk/.eslintignore

@@ -0,0 +1,3 @@
+node_modules
+dist
+cdk.out

kotlin/hello-world-lambda-cdk/.eslintrc.json

@@ -0,0 +1,15 @@
+{
+  "env": {
+    "browser": true,
+    "commonjs": true,
+    "es2021": true
+  },
+  "extends": ["eslint:recommended", "plugin:@typescript-eslint/recommended"],
+  "overrides": [],
+  "parser": "@typescript-eslint/parser",
+  "parserOptions": {
+    "ecmaVersion": "latest"
+  },
+  "plugins": ["@typescript-eslint"],
+  "rules": {}
+}

kotlin/hello-world-lambda-cdk/.gitignore

@@ -0,0 +1,10 @@
+!jest.config.js
+node_modules
+.cdk.staging
+cdk.out
+.gradle
+lambda/build
+*.js
+*.d.ts
+*.class
+cdk.context.json

kotlin/hello-world-lambda-cdk/.prettierrc

@@ -0,0 +1,7 @@
+{
+  "trailingComma": "all",
+  "tabWidth": 2,
+  "semi": true,
+  "arrowParens": "always",
+  "printWidth": 120
+}

kotlin/hello-world-lambda-cdk/README.md

@@ -0,0 +1,77 @@
+# Hello world - Kotlin Lambda (CDK) example
+
+Sample project deploying a Kotlin-based Restate service to AWS Lambda using the AWS Cloud Development Kit (CDK). This
+is functionally equivalent to the [`hello-world-lambda`](../hello-world-lambda) example but uses CDK to automate the deployment of the
+Lambda function to AWS, and to automate handler registration with a Restate.
+
+For more information on CDK, please see [Getting started with the AWS CDK](https://docs.aws.amazon.com/cdk/v2/guide/getting_started.html).
+
+* [CDK app entry point `lambda-jvm-cdk.ts`](bin/lambda-jvm-cdk.ts)
+* [CDK stack consisting of a Lambda function and providing Restate service registration](cdk/lambda-jvm-cdk-stack.ts)
+* [Kotlin Lambda handler](lambda) - based on [`hello-world-lambda`](../hello-world-lambda)
+
+## Download the example
+
+```shell
+wget https://github.com/restatedev/examples/releases/latest/download/kotlin-hello-world-lambda-cdk.zip && unzip kotlin-hello-world-lambda-cdk.zip -d kotlin-hello-world-lambda-cdk && rm kotlin-hello-world-lambda-cdk.zip
+```
+
+## Deploy
+
+**Pre-requisites:**
+
+* npm
+* gradle
+* JDK >= 11
+* Restate Cloud access (cluster id + API token)
+* AWS account, bootstrapped for CDK use
+
+Create a secret in Secrets Manager to hold the authentication token. The secret name is up to you -- we suggest
+using `/restate/` and an appropriate prefix to avoid confusion:
+
+```shell
+export AUTH_TOKEN_ARN=$(aws secretsmanager create-secret \
+    --name /restate/${CLUSTER_ID}/auth-token --secret-string ${RESTATE_AUTH_TOKEN} \
+    --query ARN --output text
+)
+```
+
+Once you have the ARN for the auth token secret, you can deploy the stack using:
+
+```shell
+npx cdk deploy \
+    --context clusterId=${CLUSTER_ID} \
+    --context authTokenSecretArn=${AUTH_TOKEN_ARN}
+```
+
+Alternatively, you can save this information in the `cdk.context.json` file:
+
+```json
+{
+  "clusterId": "...",
+  "authTokenSecretArn": "arn:aws:secretsmanager:us-east-1:123456789012:secret:/restate/.../auth-token-abc123"
+}
+```
+
+In that case, you can simply run:
+
+```shell
+npm run deploy
+```
+
+In this example, the Lambda handler function name is dynamically generated by CDK. You can see what it is from the `HandlerFunction`
+output of the CDK stack after a successful deployment.
+
+### Test
+
+You can send a test request to the Restate cluster ingress endpoint to call the newly deployed service:
+
+```shell
+curl --json '{}' -H "Authorization: Bearer ${RESTATE_API_TOKEN}" \
+    https://${CLUSTER_ID}.dev.restate.cloud:8080/greeter.Greeter/Greet
+```
+
+### Useful commands
+
+* `npm run build`   compile the Lambda handler and synthesize CDK deployment artifacts
+* `npm run deploy`  perform a CDK deployment

kotlin/hello-world-lambda-cdk/bin/lambda-jvm-cdk.ts

@@ -0,0 +1,10 @@
+#!/usr/bin/env node
+import "source-map-support/register";
+import * as cdk from "aws-cdk-lib";
+import { LambdaJvmCdkStack } from "../cdk/lambda-jvm-cdk-stack";
+
+const app = new cdk.App();
+new LambdaJvmCdkStack(app, "LambdaJvmCdkStack", {
+  clusterId: app.node.getContext("clusterId"),
+  authTokenSecretArn: app.node.getContext("authTokenSecretArn"),
+});

kotlin/hello-world-lambda-cdk/cdk.json

@@ -0,0 +1,59 @@
+{
+  "app": "npx ts-node --prefer-ts-exts bin/lambda-jvm-cdk.ts",
+  "watch": {
+    "include": ["**"],
+    "exclude": [
+      "README.md",
+      "cdk*.json",
+      "**/*.d.ts",
+      "**/*.js",
+      "tsconfig.json",
+      "package*.json",
+      "yarn.lock",
+      "node_modules",
+      "test"
+    ]
+  },
+  "context": {
+    "@aws-cdk/aws-lambda:recognizeLayerVersion": true,
+    "@aws-cdk/core:checkSecretUsage": true,
+    "@aws-cdk/core:target-partitions": ["aws", "aws-cn"],
+    "@aws-cdk-containers/ecs-service-extensions:enableDefaultLogDriver": true,
+    "@aws-cdk/aws-ec2:uniqueImdsv2TemplateName": true,
+    "@aws-cdk/aws-ecs:arnFormatIncludesClusterName": true,
+    "@aws-cdk/aws-iam:minimizePolicies": true,
+    "@aws-cdk/core:validateSnapshotRemovalPolicy": true,
+    "@aws-cdk/aws-codepipeline:crossAccountKeyAliasStackSafeResourceName": true,
+    "@aws-cdk/aws-s3:createDefaultLoggingPolicy": true,
+    "@aws-cdk/aws-sns-subscriptions:restrictSqsDescryption": true,
+    "@aws-cdk/aws-apigateway:disableCloudWatchRole": true,
+    "@aws-cdk/core:enablePartitionLiterals": true,
+    "@aws-cdk/aws-events:eventsTargetQueueSameAccount": true,
+    "@aws-cdk/aws-iam:standardizedServicePrincipals": true,
+    "@aws-cdk/aws-ecs:disableExplicitDeploymentControllerForCircuitBreaker": true,
+    "@aws-cdk/aws-iam:importedRoleStackSafeDefaultPolicyName": true,
+    "@aws-cdk/aws-s3:serverAccessLogsUseBucketPolicy": true,
+    "@aws-cdk/aws-route53-patters:useCertificate": true,
+    "@aws-cdk/customresources:installLatestAwsSdkDefault": false,
+    "@aws-cdk/aws-rds:databaseProxyUniqueResourceName": true,
+    "@aws-cdk/aws-codedeploy:removeAlarmsFromDeploymentGroup": true,
+    "@aws-cdk/aws-apigateway:authorizerChangeDeploymentLogicalId": true,
+    "@aws-cdk/aws-ec2:launchTemplateDefaultUserData": true,
+    "@aws-cdk/aws-secretsmanager:useAttachedSecretResourcePolicyForSecretTargetAttachments": true,
+    "@aws-cdk/aws-redshift:columnId": true,
+    "@aws-cdk/aws-stepfunctions-tasks:enableEmrServicePolicyV2": true,
+    "@aws-cdk/aws-ec2:restrictDefaultSecurityGroup": true,
+    "@aws-cdk/aws-apigateway:requestValidatorUniqueId": true,
+    "@aws-cdk/aws-kms:aliasNameRef": true,
+    "@aws-cdk/aws-autoscaling:generateLaunchTemplateInsteadOfLaunchConfig": true,
+    "@aws-cdk/core:includePrefixInUniqueNameGeneration": true,
+    "@aws-cdk/aws-efs:denyAnonymousAccess": true,
+    "@aws-cdk/aws-opensearchservice:enableOpensearchMultiAzWithStandby": true,
+    "@aws-cdk/aws-lambda-nodejs:useLatestRuntimeVersion": true,
+    "@aws-cdk/aws-efs:mountTargetOrderInsensitiveLogicalId": true,
+    "@aws-cdk/aws-rds:auroraClusterChangeScopeOfInstanceParameterGroupWithEachParameters": true,
+    "@aws-cdk/aws-appsync:useArnForSourceApiAssociationIdentifier": true,
+    "@aws-cdk/aws-rds:preventRenderingDeprecatedCredentials": true,
+    "@aws-cdk/aws-codepipeline-actions:useNewDefaultBranchForCodeCommitSource": true
+  }
+}

kotlin/hello-world-lambda-cdk/cdk/lambda-jvm-cdk-stack.ts

@@ -0,0 +1,56 @@
+import * as cdk from "aws-cdk-lib";
+import * as lambda from "aws-cdk-lib/aws-lambda";
+import * as restate from "@restatedev/restate-cdk";
+import { Construct } from "constructs";
+
+export class LambdaJvmCdkStack extends cdk.Stack {
+  constructor(
+    scope: Construct,
+    id: string,
+    props: {
+      clusterId: string;
+      authTokenSecretArn: string;
+    } & cdk.StackProps,
+  ) {
+    super(scope, id, props);
+
+    const greeter: lambda.Function = new lambda.Function(this, "RestateKotlin", {
+      runtime: lambda.Runtime.JAVA_21,
+      architecture: lambda.Architecture.ARM_64,
+      code: lambda.Code.fromAsset("lambda/build/libs/lambda-all.jar"),
+      handler: "dev.restate.sdk.examples.LambdaHandler",
+      timeout: cdk.Duration.seconds(10),
+      logFormat: lambda.LogFormat.JSON,
+      applicationLogLevel: "DEBUG",
+      systemLogLevel: "DEBUG",
+    });
+
+    const restateInstance = new restate.RestateCloudEndpoint(this, "RestateCloud", {
+      clusterId: props.clusterId,
+      authTokenSecretArn: props.authTokenSecretArn,
+    });
+
+    // Alternatively, you can deploy Restate on your own infrastructure like this. See the Restate CDK docs for more.
+    // const restateInstance = new restate.SingleNodeRestateInstance(this, "Restate", {
+    //   logGroup: new logs.LogGroup(this, "RestateLogs", {
+    //     retention: logs.RetentionDays.THREE_MONTHS,
+    //   }),
+    // });
+
+    const handlers = new restate.LambdaServiceRegistry(this, "RestateServices", {
+      serviceHandlers: {
+        "greeter.Greeter": greeter,
+      },
+      restate: restateInstance,
+    });
+    handlers.register({
+      metaEndpoint: restateInstance.metaEndpoint,
+      invokerRoleArn: restateInstance.invokerRole.roleArn,
+      authTokenSecretArn: restateInstance.authToken.secretArn,
+    });
+
+    new cdk.CfnOutput(this, "HandlerFunction", {
+      value: greeter.functionName,
+    });
+  }
+}

kotlin/hello-world-lambda-cdk/lambda/build.gradle.kts

@@ -0,0 +1,91 @@
+import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+import com.github.jengelman.gradle.plugins.shadow.transformers.Log4j2PluginsCacheFileTransformer
+import com.google.protobuf.gradle.id
+
+val restateVersion = "0.6.0"
+
+plugins {
+  kotlin("jvm") version "1.9.10"
+
+  id("com.google.protobuf") version "0.9.1"
+
+  // To package the dependency for Lambda
+  id("com.github.johnrengelman.shadow") version "8.1.1"
+}
+
+repositories {
+  mavenCentral()
+}
+
+dependencies {
+  // Restate SDK
+  implementation("dev.restate:sdk-api-kotlin:$restateVersion")
+  implementation("dev.restate:sdk-lambda:$restateVersion")
+  // To use Jackson to read/write state entries (optional)
+  implementation("dev.restate:sdk-serde-jackson:$restateVersion")
+
+  // Protobuf and grpc dependencies (we need the Java dependencies as well because the Kotlin dependencies rely on Java)
+  implementation("com.google.protobuf:protobuf-java:3.24.3")
+  implementation("com.google.protobuf:protobuf-kotlin:3.24.3")
+  implementation("io.grpc:grpc-stub:1.58.0")
+  implementation("io.grpc:grpc-protobuf:1.58.0")
+  implementation("io.grpc:grpc-kotlin-stub:1.4.0") { exclude("javax.annotation", "javax.annotation-api") }
+  // This is needed to compile the @Generated annotation forced by the grpc compiler
+  // See https://github.com/grpc/grpc-java/issues/9153
+  compileOnly("org.apache.tomcat:annotations-api:6.0.53")
+
+  // To specify the coroutines dispatcher
+  implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.3")
+
+  // AWS Lambda-specific logging, see https://docs.aws.amazon.com/lambda/latest/dg/java-logging.html#java-logging-log4j2
+  val log4j2version = "2.22.0"
+  implementation("org.apache.logging.log4j:log4j-core:$log4j2version")
+  implementation("org.apache.logging.log4j:log4j-layout-template-json:$log4j2version")
+  implementation("com.amazonaws:aws-lambda-java-log4j2:1.6.0")
+
+  // Testing (optional)
+  testImplementation("org.junit.jupiter:junit-jupiter:5.9.1")
+  testImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.7.3")
+  testImplementation("dev.restate:sdk-testing:$restateVersion")
+}
+
+// Setup Java/Kotlin compiler target
+java {
+  toolchain {
+    languageVersion.set(JavaLanguageVersion.of(17))
+  }
+}
+
+// Configure protoc plugin
+protobuf {
+  protoc { artifact = "com.google.protobuf:protoc:3.24.3" }
+
+  plugins {
+    id("grpc") { artifact = "io.grpc:protoc-gen-grpc-java:1.58.0" }
+    id("grpckt") { artifact = "io.grpc:protoc-gen-grpc-kotlin:1.4.0:jdk8@jar" }
+  }
+
+  generateProtoTasks {
+    all().forEach {
+      // We need both java and kotlin codegen(s) because the kotlin protobuf/grpc codegen depends on the java ones
+      it.plugins {
+        id("grpc")
+        id("grpckt")
+      }
+      it.builtins {
+        java {}
+        id("kotlin")
+      }
+    }
+  }
+}
+
+// Configure shadowJar plugin to properly transform Log4j plugin configurations - needed for AWS Lambda logger
+tasks.withType<ShadowJar> {
+  transform(Log4j2PluginsCacheFileTransformer::class.java)
+}
+
+// Configure test platform
+tasks.withType<Test> {
+  useJUnitPlatform()
+}

kotlin/hello-world-lambda-cdk/lambda/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.2-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists