(aws-lambda-nodejs): Node.js build fails with stack dependency

[spdolan]

What is the problem?

During cdk synth (or cdk deploy) operation, stacks containing Nodejs lambdas compiled using ESBuild locally will fail to bundle, even if their parent Stack has a dependency explicitly stated.

This error is non-descriptive, and states: bash: TOKEN.210: syntax error: invalid arithmetic operator (error token is ".210")

Reproduction Steps

Create two stacks:

Simple SQS queue stack:

// /project/lib/queue-stack.ts

import * as cdk from "@aws-cdk/core";
import * as sqs from '@aws-cdk/aws-sqs';

// expressed in seconds
const DEFAULT_QUEUE_TIMEOUT = 60 * 5

interface QueueStackProps extends cdk.StackProps {
  env?: cdk.Environment;
  queueName: string;
  queueTimeout?: cdk.Duration;
  needsDLQ?: boolean;
}

export class BasicQueueStack extends cdk.Stack {
  public readonly queue: sqs.Queue
  public readonly queueURL: string
  public readonly deadLetterQueue: sqs.Queue

    constructor(scope: cdk.Construct, id: string, props: QueueStackProps) {
        super(scope, id, props);

      const { queueName, queueTimeout, needsDLQ } = props;

      const queueVisibilityTimeout = queueTimeout || cdk.Duration.seconds(DEFAULT_QUEUE_TIMEOUT);
      
      const queueConfig: any = {
        queueName,
        visibilityTimeout: queueVisibilityTimeout,
        // deliveryDelay: cdk.Duration.seconds(15),
        // retentionPeriod: cdk.Duration.seconds((4 * 24 * 60 * 60)) // default value is 345600 seconds (4 days)
      }

      // add in our Dead Letter Queue 
      if (needsDLQ) {
        this.deadLetterQueue = new sqs.Queue(this, `${queueName}DLQ`, {
          queueName: `DeadLetterQueue-${queueName}`
        });

        queueConfig.deadLetterQueue = {
          queue: this.deadLetterQueue,
          maxReceiveCount: 5
        }
      }

      this.queue = new sqs.Queue(this, `${queueName}Queue`, queueConfig);
      this.queueURL = this.queue.queueUrl.toString();
    }
}

Nodejs Lambda stack.

// /project/lib/nodejs-lambda-stack.ts
import * as cdk from "@aws-cdk/core";
import * as lambda from '@aws-cdk/aws-lambda-nodejs'

interface NodejsLambdaStackProps extends cdk.StackProps {
  env?: cdk.Environment;
  functionName: string;
  functionEntry: string;
  functionProps: {[x:string]: any}
}

export class NodejsLambdaStack extends cdk.Stack {
  public readonly lambda: lambda.NodejsFunction

    constructor(scope: cdk.Construct, id: string, props: NodejsLambdaStackProps) {
        super(scope, id, props);

      const { functionName, functionEntry, functionProps: {timeout, memorySize, vpc, environmentVariables} } = props;
      
      this.lambda = new lambda.NodejsFunction(this, `${functionName}Lambda`, {
        entry: functionEntry, // accepts .js, .jsx, .ts and .tsx files
        // handler: 'handler', // defaults to 'handler'
        functionName,
        bundling: {
          // minify: true, // minify code, defaults to false
          sourceMap: true,
          define: { // Replace strings during build time
            ...environmentVariables
          },
        },
        timeout,
        memorySize, // default is 128 MB
        vpc
      });
    }
}

Reference both stacks in /bin, with Lambda Stack having SQS Queue Stack as a dependency:

// /project/bin/stack.ts
import * as cdk from '@aws-cdk/core';
import { BasicQueueStack } from "../lib/queue-stack";
import { NodejsLambdaStack } from '../lib/nodejs-function-stack'


const app = new cdk.App();
const env: { account: process.env.CDK_DEFAULT_ACCOUNT, region: process.env.CDK_DEFAULT_REGION };
const workflowName = `SomeWorkFlow`;

const queueStack = new BasicQueueStack(this, `${workflowName}QueueStack`, {
      env,
      queueName: workflowName,
      needsDLQ: true
    });

const {queue, queueURL} = queueStack;

const lambdaStack = new NodejsLambdaStack(this, `${workflowName}LambdaStack`, {
      env,
      functionName: `${workflowName}`,
      functionEntry: path.join(__dirname, `/../lambda-fns/workflow/index.ts`),
      functionProps: {
        timeout: cdk.Duration.seconds(45),
        memorySize: 256,
        vpc,
        environmentVariables: {
          'process.env.AWS_QUEUE_URL': queueURL
        }
      }
    })

lambdaStack.addDependency(queueStack);

What did you expect to happen?

Nodejs Lambda stack would:

• adhere to dependency, with ESBuild bundling after "upstream" stack.
• have a more descriptive error, regarding why bundling is failing.
• use ESBuild and be able to parse a prop variable.

What actually happened?

• ESBuild executes upon issuing the cdk synth command.
• Non-descriptive bundling error is thrown, referencing a random "Token" with number, as ESBuild does not resolve the variable value passed to the CDK Stack.
• Stack dependency order is not respected, as the "upstream" SQS Queue stack does not synthesize.

Actual error output:

$ cdk --app 'npx ts-node --prefer-ts-exts project/bin/risk-scoring.ts' synth
Bundling asset WorkflowLambdasStack/WorkflowLambda/Code/Stage...
bash: TOKEN.209: syntax error: invalid arithmetic operator (error token is ".209")
Failed to bundle asset WorkflowLambdasStack/WorkflowLambda/Code/Stage, bundle output is located at /Users/snpdolan/code/.../project/cdk.out/bundling-temp-0fff8dbe4189d9f79cf06631616af1a77ce92854cf433da41b5c5c2a90fdb579-error: Error: bash -c yarn run esbuild --bundle "/Users/snpdolan/code/.../project/lambda-fns/workflow/index.ts" --target=node14 --platform=node --outfile="/Users/snpdolan/code/.../project/cdk.out/bundling-temp-0fff8dbe4189d9f79cf06631616af1a77ce92854cf433da41b5c5c2a90fdb579/index.js" --sourcemap --external:aws-sdk --define:process.env.AWS_QUEUE_URL="${Token[TOKEN.209]}" run in directory /Users/snpdolan/code/.../project exited with status 1

CDK CLI Version

$ cdk version 1.134.0 (build dd5e12d)

Framework Version

No response

Node.js Version

node -v v14.18.1

OS

MacOS 11.6

Language

Typescript

Language Version

tsc -v Version 4.4.4

Other information

No response

[jogold]

Hi @spdolan

What are you trying to achieve here exactly?

The queueUrl is a deploy time value, it is only known after the queue stack is deployed. During synth it is represented by a token this is why you see ${Token[TOKEN.209]}. During synth/bundling those values are not resolved yet.

What you can do is pass the queueUrl as a runtime environment variable to your Lambda function.

new lambda.NodejsFunction(this, 'MyFn', {
  environment: {
    QUEUE_URL: props.queueUrl,
  }
});

Now you can use process.env.QUEUE_URL in your code and when the Lambda runs it will have the correct value.

Also note that you don't need a toString() in your queue stack. And you can also pass the queue object between stacks and do queue.queueUrl in the lambda stack and use the queue object to grant the correct permissions to your lambda function:

const fn = new lambda.NodejsFunction(this, 'MyFn', {
  environment: {
    QUEUE_URL: props.queue.queueUrl,
  }
});
queue.grantSendMessages(fn);

Since the lambda stack references the queue from the queue stack you don't need to add a dependency between the stacks.

[hugomallet]

Hi @jogold,

In the case of edge function, environment variables are not supported.
Is there any solution to get the token value in code of the edge ?

Thanks,

[jogold]

You would have to use the AWS SDK to get the queue name at runtime from a well-known place (parameter store, S3, secret, etc.).

For CloudFront functions (not Lambda@Edge) there is now a key value store but I haven't played with it yet.

[hugomallet]

Alright, thank you !

[peterwoodworth]

Thanks as always jogold 🙂

[github-actions[bot]]

Hello! Reopening this discussion to make it searchable.