Pass CDK context values per deployment environment

Question

I am using context to pass values to CDK. Is there currently a way to define project context file per deployment environment (dev, test) so that when the number of values that I have to pass grow, they will be easier to manage compared to passing the values in the command-line:

cdk synth --context bucketName1=my-dev-bucket1 --context bucketName2=my-dev-bucket2 MyStack

It would be possible to use one cdk.json context file and only pass the environment as the context value in the command-line, and depending on it's value select the correct values:

{
  ...
  "context": {
    "devBucketName1": "my-dev-bucket1",
    "devBucketName2": "my-dev-bucket2",
    "testBucketName1": "my-test-bucket1",
    "testBucketName2": "my-test-bucket2",
  }
}

But preferably, I would like to split it into separate files, f.e. cdk.dev.json and cdk.test.json which would contain their corresponding values, and use the correct one depending on the environment.

score 2 · Accepted Answer · answered Jan 20 '21 at 16:00

According to the documentation, CDK will look for context in one of several places. However, there's no mention of defining multiple/additional files.

The best solution I've been able to come up with is to make use of JSON to separate context out per environment:

"context": {
  "dev": {
    "bucketName": "my-dev-bucket"
  }
  "prod": {
    "bucketName": "my-prod-bucket"
  }
}

This allows you to access the different values programmatically depending on which environment CDK is deploying to.

let myEnv = dev         // This could be passed in as a property of the class instead and accessed via props.myEnv

const myBucket = new s3.Bucket(this, "MyBucket", {
  bucketName: app.node.tryGetContext(myEnv).bucketName
})

score 0 · Answer 2 · answered Sep 25 '21 at 04:53

You can also do so programmatically in your code:

For instance, I have a context variable of deploy_tag cdk deploy Stack\* -c deploy_tag=PROD

then in my code, i have retrieved that deploy_tag variable and I make the decisions there, such as: (using python, but the idea is the same)

bucket_name = BUCKET_NAME_PROD if deploy_tag == 'PROD' else BUCKET_NAME_DEV

this can give you a lot more control, and if you set up a constants file in your code you can keep that up to date with far less in your cdk.json that may become very cluttered with larger stacks and multiple environments. If you go this route then you can have your Prod and Dev constants file, and your context variable can inform your cdk which file to load for a given deployment.

i also tend to create a new class object with all my deployment properties either assigned or derived, and pass that object into each stack, retrieving what i need out of there.

Pass CDK context values per deployment environment

2 Answers2

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