AWS CDK: How to create lambda without code

Question

I'm trying to create an infrastructure with AWS CDK. When creating a lambda, it forces me to specify the code that's going in it.

However, that'll be the responsibility of the release pipeline.

Is there a way to create a lambda without specifying the code?

Just plug some dummy code in, or literally an empty string / file. That will cause the lambda itself to fail if invoked but that would be expected I guess. — luk2302
– luk2302, Commented Jan 3, 2023 at 8:39

fedonev · Accepted Answer · 2023-01-03 08:56:58Z

2

No. code is a required prop in the CDK Lambda Function construct^*. Use the InlineCode class as a minimal placeholder:

new lambda.Function(this, "Lambda", {
    code: new lambda.InlineCode(
        "exports.handler = async (event) => console.log(event)"
    ),
    runtime: lambda.Runtime.NODEJS_18_X,
    handler: "index.handler",
});

* It's also required for the CDK L1 CfnFunction. For what it's worth, Code is also a required input in the CreateFunction API and SDK commands.

answered Jan 3, 2023 at 8:56

fedonev

26.1k2 gold badges43 silver badges60 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

Fabio Milheiro Over a year ago

Makes sense. Thanks for sharing. But won't this overwrite the deployed function after we run the cdk deploy command next time?

fedonev Over a year ago

Yes, of course. The CDK app (via CloudFormation) is meant to own the Lambda's runtime code and infrastructure code. It's a CDK best practice.

fedonev Over a year ago

May I suggest you open a *new question* that addresses your use case? To add detail to the part you say "that'll be the responsibility of the release pipeline". I don't understand the proposed setup. I'm glad to help, but it's really a separate question.

luk2302 Over a year ago

I would not expect this to change the code during the next CDK deployment because CloudFormation is incapable of fixing drifted resources itself. During a stack update it should not even see that the code of the lambda changed in the meantime. Obviously still a bad idea since you rely on a bad CF behaviour and this would break if you were to ever change the dummy code at which point all lambdas would be overwritten.

fedonev Over a year ago

@luk2302 Your "won't overwrite" expectation holds only if: (1) OP never modifies the CDK Lambda code and (2) OP never changes the function name (which will cause a replace-redeploy).

|

Collectives™ on Stack Overflow

AWS CDK: How to create lambda without code

1 Answer 1

6 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Your Answer

Sign up or log in

Post as a guest

Related