fix(aws-cdk-lib): Python 3.6 dperecation for Lambda breaks

[AlphaDork]

Hi David, working through your pluralsight course (which is fantastic! BTW). Implementing Serverless Web Application Hosting and Delivery on AWS - I am in the section where you first deploy the React App using the CDK... and I'm getting an error.

After some sleuthing - there is what I think is a breaking change in the aws-cdk-lib library where they deprecated python3.6 in favor of python3.9 as of like 7/22/22.

See the related AWS CL deprecating Python 3.6 here: aws/aws-cdk#20647

Here is the Error message I get on deployment:

Resource handler returned message: "The runtime parameter of python3.6 is no longer supported for creating or updating AWS Lambda functions. We recommend you use the new runtime (python3.9) while creating or updating functions. (Service: L
ambda, Status Code: 400, Request ID: 5411f42d-3a3e-4c21-af63-ce423f3dc0f4)" (RequestToken: c0c306e7-3499-a21a-26d5-d3fcb99154ff, HandlerErrorCode: InvalidRequest)```

[gauravinthevalley]

@AlphaDork

I ran into the exact same issue. After some googling around, I found out that I had to migrate to v2 of the AWS CDK. I did that and now the code below wouldn't work.

`
new cwt.WebAppDeployment(this, 'WebAppDeploy', {

        baseDirectory: props.baseDirectory,

        relativeWebAppPath: props.relativeWebAppPath,

        webDistribution: this.webDistribution,

        webDistributionPaths: ['/*'],

        buildCommand: 'yarn build',

        buildDirectory: 'build',

        bucket: props.hostingBucket,

        prune: true

    })

`

After googling around and borrowing a bit from @davidtucker 's code here https://github.com/davidtucker/cdk-webapp-tools/blob/main/src/WebAppDeployment.ts (line 143 onward), I changed the code block above to the one below:

`
new s3Deploy.BucketDeployment(this, 'WebAppDeploy', {

        prune: true,

        distribution: this.webDistribution,

        distributionPaths: ['/*'],

        sources: [s3Deploy.Source.asset(path.join(__dirname, '../../../webapp/build'))],

        destinationBucket: props.hostingBucket,

    });

`

And now it works!

I also had to run yarn build manually under the webapp directory along with deleting all of the stacks and bootstrapping again; at one point I think I also deleted cdk.out. After the CDK v1 to v2 migration which essentially was changing imports and updating package.json and cdk.json under the infrastructure directory , npx cdk deploy was seamless.

Here's that updated package.json:

`
{

"name": "@ps-serverless/infrastructure",

"version": "0.1.0",

"bin": {

"infrastructure": "bin/infrastructure.js"

},

"scripts": {

"build": "tsc",

"watch": "tsc -w",

"test": "jest",

"cdk": "cdk"

},

"devDependencies": {

"@aws-cdk/assert": "^2.35.0",

"@types/jest": "^26.0.10",

"@types/node": "10.17.27",

"@types/source-map-support": "^0.5.4",

"aws-cdk": "2.33.0",

"esbuild": "^0.14.53",

"jest": "^26.4.2",

"ts-jest": "^26.2.0",

"ts-node": "^9.0.0",

"typescript": "~3.9.7"

},
"dependencies": {

"@aws-cdk/core": "^1.167.0",

"aws-cdk-lib": "2.33.0",

"cdk-webapp-tools": "2.10.4",

"constructs": "^10.0.0",

"source-map-support": "^0.5.16"

}

}
`

And here's the updated cdk.json:
`
{

"app": "npx ts-node --prefer-ts-exts bin/infrastructure.ts"

}
`