Aws-cdk: Parameter valueAsNumber not returning correct number.

[amwill04]

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• I'm submitting a ...

  • [X ] :beetle: bug report
  • [ ] :rocket: feature request
  • [ ] :books: construct library gap
  • [ ] :phone: security issue or vulnerability => Please see policy
  • [ ] :question: support request => Please see note at the top of this template.

• What is the current behavior?
  If the current behavior is a :beetle:bug:beetle:: Please provide the steps to reproduce

Create a CfnParameter with type 'Number' and a default value.
Use that value somewhere with parameter.valueAsNumber
Produces a value of -1.8881545897087546e+289

cosnt param = new CfnParameter(this, 'RedendtionPeriod', {
            description: 'SQS redention period in seconds 60 - 1209600 [14400]',
            type: 'Number',
            default: 14400,
            minValue: 60,
            maxValue: 1209600,
            constraintDescription: 'Must be between 60 and 1209600',
        });

param.valueAsNumber // -1.8881545897087546e+289

• What is the expected behavior (or behavior of feature suggested)?
  Return the token for that value.

• Please tell us about your environment:

  • CDK CLI Version: 1.2.0
  • Module Version: 1.2.0
  • OS: OSX Mojave
  • Language: Typescript

[amwill04]

So from what I understand this isnt a bug but how it is supposed to work. The number is an id of the token. However you are then unable to use this with any construct that takes a type number as typescript will pass type checking but you are providing it with the wrong number - not a reference.

I suspect this because I am abusing the API by mixing lower API Cfn constructs and the higher level constructs. However it seems missleading as valueAsString is usable

import { CfnParameter } from '@aws-cdk/core';
import { Queue, QueueEncryption } from '@aws-cdk/aws-sqs';
const redemptionPeriod = new CfnParameter(this, 'RedendtionPeriod', {
            description: 'SQS redention period in seconds 60 - 1209600 [14400]',
            type: 'Number',
            default: 14400,
            minValue: 60,
            maxValue: 1209600,
            constraintDescription: 'Must be between 60 and 1209600',
        });

sqs = new Queue(this, 'MISQS', {
            queueName: 'daily-journey-to-parquet-queue',
            retentionPeriod: Duration.seconds(redentionPeriod.valueAsNumber), // This pass typechecking but will at best fail and at worst pass with the incorrect number.
            deliveryDelay: Duration.seconds(0),
            maxMessageSizeBytes: 1024,
            receiveMessageWaitTime: Duration.seconds(20),
            visibilityTimeout: Duration.seconds(60),
            encryption: QueueEncryption.KMS,
        });

[amwill04]

Closing this as I dont believe its a bug its simply a limitation.

[nagupta92]

This is a bug, since the function valueAsNumber is suppose to return the value of the parameter not the reference as per the doc -

Can we please re-open this ?

[amwill04]

@nagupta92 Ive reopened.

[eladb]

This is by design. Parameters are "late bound". Their values are only resolved during deployment and available only to CloudFormation. .valueAsNumber returns a token to the value as it will be resolved _during deployment_. It is impossible to know the value of the parameter during synthesis.

Closing.

[amwill04]

Hey @eladb this is a bug specifically with SQS my above example with output the following error:

message retention period must be 60 seconds or more, but -1.8881545897087585e+289 was provided

[amwill04]

Ill open a better bug report