Danielle HeberlingAs of re:Invent 2021, CDK v2 is now generally available. 🎉
This post includes a brief walkthrough on upgrading a project from v1 -> v2 as well as some personal opinions. I’ll be using this notes app that we build previously to demo. If you want to skip ahead, the finished source code is on Github.
Here’s we go. Let’s upgrade the application!
Step 1: Disable feature flags in cdk.json
Many of the feature flags from v1 are now included in v2 and/or are no longer relevant, so let’s disable all flags.
Before
{
"app": "npx ts-node --prefer-ts-exts bin/note-service.ts",
"context": {
"@aws-cdk/core:enableStackNameDuplicates": true,
"aws-cdk:enableDiffNoFail": true,
"@aws-cdk/core:stackRelativeExports": true,
"@aws-cdk/aws-ecr-assets:dockerIgnoreSupport": true,
"@aws-cdk/aws-secretsmanager:parseOwnedSecretName": true,
"@aws-cdk/aws-kms:defaultKeyPolicies": true,
"@aws-cdk/aws-s3:grantWriteWithoutAcl": true
}
}
After
{
"app": "npx ts-node --prefer-ts-exts bin/note-service.ts",
"context": {
"@aws-cdk/aws-apigateway:usagePlanKeyOrderInsensitiveId": false,
"@aws-cdk/aws-cloudfront:defaultSecurityPolicyTLSv1.2_2021": false,
"@aws-cdk/aws-rds:lowercaseDbIdentifier": false,
"@aws-cdk/core:stackRelativeExports": false
}
}
Step 2: Update package.json dependencies
One of the features of CDK v2 is having mostly everything in a single library, aws-cdk-lib. Hopefully this can help alleviate some of the pain that developers experienced with keeping all packages up to date and in sync.
Let’s focus on the devDependencies section of the package.json. In v2, we also need to add a peerDependencies section.
Before
"devDependencies": {
"@aws-cdk/assert": "^1.139.0",
"@aws-cdk/aws-appsync": "^1.139.0",
"@aws-cdk/aws-dynamodb": "^1.139.0",
"@aws-cdk/aws-lambda": "^1.139.0",
"@aws-cdk/aws-lambda-nodejs": "^1.139.0",
"@aws-cdk/aws-logs": "^1.139.0",
"@aws-cdk/core": "^1.139.0",
"@types/jest": "^27.4.0",
"@types/node": "^17.0.8",
"aws-cdk": "^1.139.0",
"esbuild": "^0.14.11",
"jest": "^27.4.7",
"ts-jest": "^27.0.2",
"ts-node": "^10.4.0",
"typescript": "^4.5.4"
},
After
"peerDependencies": {
"aws-cdk-lib": "^2.8.0",
"constructs": "^10.0.36"
},
"devDependencies": {
"@aws-cdk/assert": "^2.8.0",
"@aws-cdk/aws-appsync-alpha": "^2.8.0-alpha.0",
"@types/jest": "^27.4.0",
"@types/node": "^17.0.8",
"aws-cdk-lib": "^2.8.0",
"constructs": "^10.0.36",
"esbuild": "^0.14.11",
"jest": "^27.4.7",
"ts-jest": "^27.0.2",
"ts-node": "^10.4.0",
"typescript": "^4.5.4"
},
One thing to note in this specific project is that the AppSync dependency is currently in alpha. Personally, I would recommend exercising extreme caution before using it in a business critical application.
Step 3: Update import statements in the code
Since we’ve changed some dependencies in our package.json, we should update our import statements to match.
Here’s an example of what that looks like
Before
import { CfnOutput, Construct, RemovalPolicy, Stack, StackProps } from '@aws-cdk/core';
import { FieldLogLevel, GraphqlApi, Schema } from '@aws-cdk/aws-appsync';
import { AttributeType, BillingMode, Table } from '@aws-cdk/aws-dynamodb';
import { Architecture, Runtime } from '@aws-cdk/aws-lambda';
import { NodejsFunction } from '@aws-cdk/aws-lambda-nodejs';
import { RetentionDays } from '@aws-cdk/aws-logs';
After
import { Construct } from 'constructs';
import { Stack, StackProps } from 'aws-cdk-lib';
import { CfnOutput, RemovalPolicy } from 'aws-cdk-lib';
import { AttributeType, BillingMode, Table } from 'aws-cdk-lib/aws-dynamodb';
import { Architecture, Runtime } from 'aws-cdk-lib/aws-lambda';
import { NodejsFunction } from 'aws-cdk-lib/aws-lambda-nodejs';
import { RetentionDays } from 'aws-cdk-lib/aws-logs';
import { FieldLogLevel, GraphqlApi, Schema } from '@aws-cdk/aws-appsync-alpha';
Step 4: Bootstrap your environment for v2
If you’ve previously been working with v1, you’ll need to re-bootstrap your environment so you can deploy using CDK v2.
To do this run the following in your console after you’ve installed CDK v2 on your machine.
cdk bootstrap aws://<your-account-number>/<your-region>
Closing thoughts
From my end, the upgrade process was seamless. Keep in mind that this was just a small personal project not using many constructs, so your experience might possibly differ. Overall, the team at AWS did a great job writing documentation on this topic.
Despite the announcement of CDK v2 moving out of developer preview, I did notice that many constructs for v2 are still in alpha…so that seemed somewhat misleading.
I plan to wait a bit before upgrading business critical applications to ensure that constructs will work reliably with the new version. I am pretty excited about all of the improvements under the hood and look forward to using it more extensively in the future.
