AWS CDK: run external build command in CDK sequence?

Question 1

Is it possible to run an external build command as part of a CDK stack sequence? Intention: 1) create a rest API, 2) write rest URL to config file, 3) build and deploy a React app:

import apigateway = require('@aws-cdk/aws-apigateway');
import cdk = require('@aws-cdk/core');
import fs = require('fs')
import s3deployment = require('@aws-cdk/aws-s3-deployment');

export class MyStack extends cdk.Stack {

  const restApi = new apigateway.RestApi(this, ..);
  fs.writeFile('src/app-config.json', 
    JSON.stringify({ "api": restApi.deploymentStage.urlForPath('/myResource') }))

  // TODO locally run 'npm run build', create 'build' folder incl rest api config

  const websiteBucket = new s3.Bucket(this, ..)
  new s3deployment.BucketDeployment(this, .. {
      sources: [s3deployment.Source.asset('build')],
      destinationBucket: websiteBucket
  }) 
}

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

import apigateway = require('@aws-cdk/aws-apigateway');

import cdk = require('@aws-cdk/core');

import fs = require('fs')

import s3deployment = require('@aws-cdk/aws-s3-deployment');

export class MyStack extends cdk.Stack {

const restApi = new apigateway.RestApi(this, ..);

fs.writeFile('src/app-config.json',

JSON.stringify({ "api": restApi.deploymentStage.urlForPath('/myResource') }))

// TODO locally run 'npm run build', create 'build' folder incl rest api config

const websiteBucket = new s3.Bucket(this, ..)

new s3deployment.BucketDeployment(this, .. {

sources: [s3deployment.Source.asset('build')],

destinationBucket: websiteBucket

})

}

Question 2

Unfortunately, it is not possible, as the necessary references are only available after deploy and therefore after you try to write the file (the file will contain cdk tokens).

I personally have solved this problem by telling cdk to output the apigateway URLs to a file and then parse it after the deploy to upload it so a S3 bucket, to do it you need:

deploy with the output file options, for example:
cdk deploy -O ./cdk.out/deploy-output.json
In ./cdk.out/deploy-output.json you will find a JSON object with a key for each stack that produced an output (e.g. your stack that contains an API gateway)
manually parse that JSON to get your apigateway url
create your configuration file and upload it to S3 (you can do it via aws-sdk)

Of course, you have the last steps in a custom script, which means that you have to wrap your cdk deploy. I suggest to do so with a nodejs script, so that you can leverage aws-sdk to upload your file to S3 easily.

AWS CDK: run external build command in CDK sequence?

Question:

Answer:

Leave a Reply Cancel reply