Core

These are the core constructs and classes of this library.

• Tier – A class that represents different deployment tiers (i.e. DTAP)
• Workload – A construct meant to serve as the container for stacks; it can load context values from a JSON file

Tier

The Tier class is a glorified enum. It represents the deployment tier of a workload.

Tier has four static properties: DEVELOPMENT, TESTING, ACCEPTANCE, and PRODUCTION. Each is an instance of Tier.

Tier has two properties: an id and a label. For instance, dev and Development.

You can create any arbitrary tier you like, using the constructor.

import { Tier } from "shady-island";

const tier = new Tier("sandbox", "Sandbox");

Tier has three instance methods: applyTags, assignTo, and matches.

.applyTags(construct)

The applyTags method adds a new tag to the provided construct: the name is DeploymentTier, the value is the tier’s label.

import { App, Stack } from "aws-cdk-lib";
import { Tier } from "shady-island";

const app = new App();
const stack = new Stack(app, {});
const tier = Tier.DEVELOPMENT;
tier.applyTags(stack);

.assignTo(construct) and .of(construct)

The assignTo method associates a tier with the provided construct and all its descendants. The static of method is used to retrieve a construct’s tier.

import { App, Stack } from "aws-cdk-lib";
import { Topic } from "aws-cdk-lib/aws-sns";
import { Tier } from "shady-island";

const app = new App();
const stack = new Stack(app, {});
const topic = new Topic(stack, {});
const tier = Tier.PRODUCTION;
tier.assignTo(stack);
Tier.of(app); // undefined
Tier.of(stack); // Tier.PRODUCTION
Tier.of(topic); // Tier.PRODUCTION

Assigning a different tier to a construct beneath a construct with a defined tier will register an error annotation and prevent the stack from being deployed.

.matches()

The matches method is used to compare two Tier objects.

import { Tier } from "shady-island";

const tier = Tier.TESTING;
tier.matches(Tier.PRODUCTION); // false
tier.matches(Tier.TESTING); // true

.parse(string)

The Tier class also has a static method: parse. You can use this method to determine the corresponding Tier for a given string (see the API documentation for the different values that produce one of the four static properties).

import { Tier } from "shady-island";

// MY_DEPLOYMENT_TIER=live
const tier = Tier.parse(process.env.MY_DEPLOYMENT_TIER);
Tier.PRODUCTION.matches(tier); // true