Hi, I’m trying to add a new Alias to a Lambda function.

new aws.lambda.Alias(
  `alias-${stageSanitized}-new`,
  {
    name: 'SER001',
    functionVersion: lambdaFN.version,
    functionName: lambdaFN.name,
    description: 'Alias for SER001 environment',
  },
  { parent: lambdaFN, protect: true },
);

I already have an alias created for a given version of the same Lambda. But when I make

pulumi update

, I get that the existing Alias will get deleted. What am I missing? So both Alias have different names: one for the

env

, like

dev

, and the other, simulating a feature (

SER001

). I even added the protected flag…

Are you changing the Pulumi name of the Alias at the same time? If you change the name (that is, if stageSanitized changes, or if you add the -new suffix), then it is an entirely different resource as far as Pulumi is concerned, and it will delete the old one.

@little-cartoon-10569 thanks for the reply! I’m trying to set up (understand at this point) the way to use Alias on a Lambda function to CI or feature branching (to use the same lambda but with the alias pointing to a specific version of the Lambda, maybe it’s not the best way). So for context I have the lambdas deployment like this:

const myLayer = new aws.lambda.LayerVersion("layer-dev", args);

const myFunction = new aws.lambda.Function("lambda-function1", {
  ...args,
  name: 'my-function-dev',
  layers: [myLayer.arn],
  publish: true
});

new aws.lambda.Alias("alias-dev", {
  name: 'dev',
  functionVersion: myFunction.version,
  functionName: myFunction.arn,
})

[stageSanitized = “dev”] So with that scenario, I tried two options: • Same Pulumi stack, changed the stageSanitized from

dev

(code above) to

SER001

(feature branch). And Pulumi deletes the dev Alias. Makes sense, as it’s not in the new Pulumi desired final state. Is there a way NOT to be deleted, and leave it as is? Because I need it to stay there, pointing to the Lambda published version as it was. So, basically could point me to a direction to understand if there’s a way to work with Lambda’s aliases with Pulumi? • Different Pulumi stack, or maybe this is the way to go. Instead of using the Alias on a Lambda, it’s needed to make a complete deployment with another stack name, with the stack reference in the resources naming (so there’s no collision, as I’m forcing the AWS resources names, for references purposes). Thanks!

So long as you don't change the Pulumi name, it won't delete the Alias, just update it.

@little-cartoon-10569 Thanks! I was thinking on it, and on how Pulumi works I understand now that there’s only the new stack way. One more question on it, if I do create a new stack and make the deployment of the same Pulumi bit of code: • Lambda code references are only with the environment =

dev

(no reference to the actual stack name), so Pulumi name and AWS resource name for Layer and Lambda are the same between stacks. • But, the Alias is related to the Stack:

dev

||

ser001

. Pointing to the same Lambda. On the Lambda code for the new deployment (

ser001

Stack), wouldn’t I get an error because the naming is the same (Pulumi and AWS resource)? Or how can I make this new deployment for another stack be just a new version on the same Lambda?

I'm afraid I don't understand the question. Are you asking how to avoid creating two lambdas? Only create the lambda in one stack (

if ("dev" == Pulumi.getStack()

), and export the stack reference. In the other stack, use the stack reference when creating the alias.