AWS Lookups for cdk8s

This library provides a simple way to lookup AWS resources from your cdk8s project during synthesis time. Lookups are being cached in the cdk8s.context.json file in the root of your project. Values are looked up using the AWS SDK if they are not in the cache, and then if found, stored in the cache. Subsequent synth runs will then use the cached values. If you want to refresh the lookup, you will have to evict the value from the cache. You can do that by deleting the value from the cdk8s.context.json file, or to delete the whole file.

In order to perform the lookup using the AWS SDK, you will need to have the AWS credentials set up on your machine. By default, the library will try to use the aws-cdk lookup pattern, which tries to sts assume the role pattern arn:aws:iam::accountid:role/cdk-hnb659fds-lookup-role-accountid-region-id, but if it fails to do so because this was not set up, it will use the standard AWS Credential flow for the lookup. If you are unfamiliar on how to configure credentials for AWS, please refer to the AWS SDK documentation or the AWS CDK documentation.

Cloudformation Outputs Lookup

The AwsCloudformationOutputs is able to lookup any StackOutput defined by your deployed AWS CDK application. It does that by implementing the lookup Pattern of aws-cdk in cdk8s, using the lookupOutput() method.

Usage:

You can simply use the AwsCloudformationOutputs class in your cdk8s project. The lookupOutput method will return the value of the output you are looking for at synthesis time.

import { Chart } from "cdk8s";
import * as kplus from "cdk8s-plus";
import { AwsCloudformationOutputs } from "cdk8s-aws-lookups";

class MyChart extends Chart {
  constructor(scope: Construct, id: string, stackName: string) {
    super(scope, id);

    const cfOutputs = new AwsCloudformationOutputs(stackName, {
      account: awsAccID,
      region: awsRegion,
    });
    const databaseConnectionString = cfOutputs.lookupOutput(
      "DatabaseConnectionString"
    );

    const deployment = new kplus.Deployment(this, "MyDeployment");
    const container = deployment.addContainer({
      image: "my-app-image",
      env: {
        DATABASE_CONNECTION_STRING: databaseConnectionString,
      },
    });
  }
}

import { ApiObject, App, Chart, Testing } from "cdk8s";
import { Construct } from "constructs";
import { AwsCloudformationOutputs } from "cdk8s-aws-lookups";

class MyExampleChart extends Chart {
  constructor(scope: Construct, id: string) {
    super(scope, id);

    const awsAccID = process.env.AWS_ACC_ID || "111111111111";
    const stackName = process.env.STACK_NAME || "my-stack";
    const awsRegion = process.env.AWS_REGION || "eu-west-1";

    if (!awsAccID || !stackName) {
      throw new Error(
        "AWS_ACC_ID and STACK_NAME environment variables must be exported for the synth to to run."
      );
    }

    const cfOutputs = new AwsCloudformationOutputs(stackName, {
      account: awsAccID,
      region: awsRegion,
    });
    const databaseConnectionString = cfOutputs.lookupOutput("your-output-name");

    new ApiObject(this, "ConfigMap", {
      apiVersion: "v1",
      kind: "ConfigMap",
      data: {
        Outputs: {
          DATABASE_CONNECTION_STRING: databaseConnectionString,
        },
      },
    });
  }
}

AWS SSM Parameters Lookup

The AwsSsmParameters is able to lookup any SSM Parameter defined by your deployed AWS CDK application. It does that by implementing the lookup Pattern of aws-cdk in cdk8s, using the lookupParameter() method.

Usage:

class MyTestChart extends Chart {
  constructor(scope: Construct, id: string) {
    super(scope, id);

    const awsAccID = process.env.AWS_ACC_ID; // or pass in via constructor
    const awsRegion = process.env.AWS_REGION || "eu-west-1";

    const awsSsmParameters = new AwsSsmParameters({
      account: awsAccID,
      region: awsRegion,
    });
    const specificParameterValue = ssmParameters.lookupParameter("/aaa/test");

    new ApiObject(this, "ConfigMap", {
      apiVersion: "v1",
      kind: "ConfigMap",
      data: {
        Outputs: {
          SPECIFIC_PARAMETER_VALUE: specificParameterValue,
        },
      },
    });
  }
}