12.4Pulumi Stacks for Ephemeral Environments

Pulumi stacks are the equivalent of Terraform workspaces but with programmatic control:

// index.ts -- Pulumi stack per PR
import * as pulumi from "@pulumi/pulumi";
import * as aws from "@pulumi/aws";

const stack = pulumi.getStack(); // e.g., "pr-142"
const isEphemeral = stack.startsWith("pr-");

const db = new aws.rds.Instance("main", {
    instanceClass: isEphemeral ? "db.t4g.micro" : "db.r6g.xlarge",
    allocatedStorage: isEphemeral ? 20 : 500,
    skipFinalSnapshot: isEphemeral, // No snapshot needed for PR envs
    identifier: `myapp-${stack}-db`,
    engine: "postgres",
    engineVersion: "16",
});

const service = new aws.ecs.Service("app", {
    desiredCount: isEphemeral ? 1 : 3,
    // ... other configuration
});

export const dbEndpoint = db.endpoint;
export const previewUrl = isEphemeral
    ? pulumi.interpolate`https://${stack}.preview.example.com`
    : undefined;