Pulumi Infrastructure as Code

Quick Guide: Define cloud infrastructure in TypeScript with full type safety. Use ComponentResource to encapsulate reusable infrastructure patterns. Pass { parent: this } to all child resources inside components. Use pulumi.interpolate for string building with Outputs (not string concatenation). Never create resources inside .apply(). Use Config.requireSecret() for sensitive values. Prefer transforms over deprecated transformations. Always call this.registerOutputs() at the end of component constructors.

---

<critical_requirements>

CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST pass { parent: this } to ALL child resources inside a ComponentResource -- omitting it breaks the resource tree and state tracking)

(You MUST use pulumi.interpolate for string building with Outputs -- string concatenation silently produces [object Object])

(You MUST NEVER create resources inside .apply() -- they will not appear in pulumi preview and cause ordering issues)

(You MUST use Config.requireSecret() for sensitive values -- Config.require() stores values as plaintext in state)

(You MUST call this.registerOutputs() at the end of every ComponentResource constructor -- omitting it prevents output tracking)

</critical_requirements>

---

Detailed Resources:

• examples/core.md - Resource definitions, component resources, naming, Outputs, config/secrets
• examples/advanced.md - Stack references, transforms, dynamic providers, Automation API, policy packs
• reference.md - Decision frameworks, resource options table, API reference, CLI commands

---

Auto-detection: Pulumi, @pulumi/pulumi, @pulumi/aws, @pulumi/gcp, @pulumi/azure, @pulumi/kubernetes, pulumi.ComponentResource, pulumi.CustomResource, pulumi.Output, pulumi.Config, pulumi.interpolate, pulumi.all, registerOutputs, StackReference, ComponentResourceOptions, CustomResourceOptions, dynamic.Resource, dynamic.ResourceProvider, LocalWorkspace, InlineProgramArgs, Automation API, CrossGuard, PolicyPack

When to use:

• Defining cloud infrastructure in TypeScript with type-safe resource APIs
• Creating reusable infrastructure components with ComponentResource
• Managing multi-stack architectures with stack references
• Handling secrets and environment-specific configuration
• Building self-service infrastructure platforms with the Automation API
• Writing compliance policies with CrossGuard policy packs

When NOT to use:

• One-off shell scripts that create a single resource (use the cloud CLI directly)
• Projects where the team has no TypeScript experience (consider other IaC language options)

Key patterns covered:

• Resource definitions with typed inputs and auto-naming
• ComponentResource encapsulation (parent, naming, registerOutputs)
• Outputs: apply, all, interpolate, and lifting
• Config and secrets management (Config.require, Config.requireSecret, pulumi.secret)
• Stack references for cross-stack data sharing
• Resource options (dependsOn, protect, aliases, ignoreChanges, transforms)
• Dynamic providers for custom CRUD resources
• Automation API for programmatic stack management
• CrossGuard policy packs for compliance enforcement

---

Philosophy

Pulumi treats infrastructure as real code, not configuration files. TypeScript gives you type safety, IDE autocompletion, refactoring tools, and the full Node.js ecosystem. Resources are objects, dependencies are automatic, and reuse happens through functions and classes -- not a custom module language.

Core principles:

• Resources are objects: Every cloud resource is a TypeScript class instance with typed inputs and outputs
• Dependencies are automatic: When you pass one resource's output as another's input, Pulumi infers the dependency graph
• Reuse through components: ComponentResource encapsulates multiple resources into a single logical unit with its own inputs and outputs
• Outputs are promises: Output<T> represents a value that may not be known until after deployment -- use apply, all, or interpolate to work with them, never unwrap manually
• State is managed: Pulumi tracks every resource in state -- changing a logical name or moving a resource between files triggers a delete-and-recreate unless you use aliases

---

Core Patterns

Pattern 1: Resource Definitions

Every resource takes a logical name (used for state tracking), an args bag (typed inputs), and optional resource options.

const bucket = new aws.s3.Bucket(
  "data-bucket",
  {
    versioning: { enabled: true },
    lifecycleRules: [
      { enabled: true, expiration: { days: BUCKET_EXPIRY_DAYS } },
    ],
  },
  { protect: true },
); // Prevent accidental deletion

Key points: Logical names must be unique per type within a stack. Pulumi auto-appends a random suffix to the physical name to prevent collisions. Use protect: true on critical resources. Export outputs for cross-stack consumption.

See examples/core.md for resource naming, auto-naming configuration, and provider options.

---

Pattern 2: ComponentResource Encapsulation

Wrap related resources in a ComponentResource to create reusable infrastructure units.

import * as pulumi from "@pulumi/pulumi";
import * as aws from "@pulumi/aws";

interface StaticSiteArgs {
  indexDocument?: string;
  errorDocument?: string;
}

class StaticSite extends pulumi.ComponentResource {
  public readonly bucketName: pulumi.Output<string>;
  public readonly websiteUrl: pulumi.Output<string>;

  constructor(
    name: string,
    args: StaticSiteArgs,
    opts?: pulumi.ComponentResourceOptions,
  ) {
    super("myinfra:web:StaticSite", name, args, opts);

    const bucket = new aws.s3.BucketV2(`${name}-bucket`, {}, { parent: this });

    const website = new aws.s3.BucketWebsiteConfigurationV2(
      `${name}-website`,
      {
        bucket: bucket.id,
        indexDocument: { suffix: args.indexDocument ?? "index.html" },
        errorDocument: { key: args.errorDocument ?? "error.html" },
      },
      { parent: this },
    );

    this.bucketName = bucket.id;
    this.websiteUrl = website.websiteEndpoint;
    this.registerOutputs({
      bucketName: this.bucketName,
      websiteUrl: this.websiteUrl,
    });
  }
}

Why good: child resources use { parent: this }, name is prefixed from parent, registerOutputs is called, type token follows pkg:module:Type format

See examples/core.md for complete component patterns with provider inheritance and multi-resource components.

---

Pattern 3: Working with Outputs

Outputs represent values resolved after deployment. Never use string concatenation -- use interpolate, apply, or all.

// interpolate -- tagged template for string building (preferred)
const url = pulumi.interpolate`https://${bucket.bucketRegionalDomainName}/index.html`;

// apply -- transform a single output
const upper = bucket.id.apply((id) => id.toUpperCase());

// all -- combine multiple outputs
const endpoint = pulumi
  .all([lb.dnsName, listener.port])
  .apply(([dns, port]) => `http://${dns}:${port}`);

// Lifting -- access properties directly on resource outputs
const subnetId = vpc.subnets[0].id; // No apply needed for known properties

Why good: interpolate handles Output values transparently, all waits for multiple values, lifting avoids unnecessary apply calls

Gotcha: Resources created inside .apply() will not appear in pulumi preview and may cause ordering issues. Always pass Outputs directly as inputs to other resources.

See examples/core.md for Output patterns, pulumi.output() wrapping, and the apply anti-pattern.

---

Pattern 4: Config and Secrets

Use pulumi.Config for stack-specific values. Use requireSecret for sensitive data -- it encrypts the value in state.

const config = new pulumi.Config();

// Plain config values
const region = config.require("region"); // Fails if missing
const nodeCount = config.getNumber("nodeCount"); // Returns undefined if missing

// Secret values -- encrypted in state
const dbPassword = config.requireSecret("dbPassword");
const apiKey = config.getSecret("apiKey");

// Mark programmatic values as secret
const connectionString = pulumi.interpolate`postgres://admin:${dbPassword}@${db.endpoint}/mydb`;
// connectionString is automatically secret because dbPassword is secret

// Explicitly mark a value as secret
const token = pulumi.secret(generateToken());

Key point: Any Output derived from a secret is automatically marked secret. You do not need to re-mark derived values.

See examples/core.md for namespaced config, secret outputs, and config set CLI commands.

---

Pattern 5: Resource Options

Resource options control lifecycle behavior. The most important ones:

const db = new aws.rds.Instance(
  "primary-db",
  {
    /* ... */
  },
  {
    protect: true, // Prevent accidental deletion
    dependsOn: [vpc, securityGroup], // Explicit ordering
    ignoreChanges: ["tags"], // Ignore drift on specific props
    aliases: [{ name: "old-db-name" }], // Rename without recreating
    retainOnDelete: true, // Keep cloud resource on pulumi destroy
    deleteBeforeReplace: true, // For resources that must be unique
    replaceOnChanges: ["engine"], // Force replace on specific changes
    provider: usEastProvider, // Explicit provider (region, account)
  },
);

Gotcha: Changing a resource's logical name or parent causes Pulumi to delete and recreate it. Use aliases to rename safely.

See reference.md for the complete resource options table.

---

Pattern 6: Stack References

Share outputs between stacks using StackReference.

// In the networking stack: export outputs
export const vpcId = vpc.id;
export const subnetIds = subnets.map((s) => s.id);

// In the application stack: consume outputs
const networkStack = new pulumi.StackReference("myorg/networking/prod");
const vpcId = networkStack.getOutput("vpcId");
const subnetIds = networkStack.getOutput("subnetIds");

// requireOutput fails if the output doesn't exist (safer than getOutput)
const vpcIdRequired = networkStack.requireOutput("vpcId");

See examples/advanced.md for stack reference patterns and getOutputDetails.

---

Pattern 7: Transforms

Apply transformations to resources and their children. Use transforms (not the deprecated transformations). Transforms receive an args object with type, props, and opts, and return a modified result or undefined to skip.

// Resource-level: apply tags to all taggable children of a component
const vpc = new MyVpcComponent(
  "vpc",
  {},
  {
    transforms: [
      (args) => {
        if (isTaggable(args.type)) {
          return {
            props: {
              ...args.props,
              tags: { ...args.props["tags"], ManagedBy: "pulumi" },
            },
            opts: args.opts,
          };
        }
        return undefined;
      },
    ],
  },
);

Key difference from deprecated transformations: transforms support modifying packaged component children (awsx, eks), support async callbacks, and do not pass a Resource object.

See examples/advanced.md for stack-level transforms, option modification, and migration from transformations.

---

Pattern 8: Automation API

Run Pulumi programmatically without the CLI -- for self-service platforms, integration tests, or custom deployment tooling.

const stack = await LocalWorkspace.createOrSelectStack({
  stackName: "dev",
  projectName: "my-platform",
  program: async () => {
    const bucket = new aws.s3.Bucket("auto-bucket");
    return { bucketName: bucket.id };
  },
});
const upResult = await stack.up({ onOutput: console.log });

Key point: The Automation API requires the Pulumi CLI to be installed and on PATH -- it uses the CLI's engine under the hood.

See examples/advanced.md for preview, destroy, local program mode, config setup, and stack output retrieval.

---

<red_flags>

RED FLAGS

High Priority:

• Creating resources inside .apply() -- They won't appear in pulumi preview, cause ordering issues, and break the dependency graph. Pass Outputs directly as resource inputs.
• Missing { parent: this } in ComponentResource children -- Resources appear at the root of the state tree, breaking logical grouping and component delete cascading.
• String concatenation with Outputs -- "https://" + bucket.id produces [object Object]. Use pulumi.interpolate instead.
• Using Config.require() for passwords/keys -- Stores the value as plaintext in state. Use Config.requireSecret() to encrypt.
• Forgetting this.registerOutputs() -- Component outputs won't be tracked properly in state or available via stack references.
• Changing logical names without aliases -- Pulumi deletes and recreates the resource. Use aliases: [{ name: "old-name" }] to rename safely.

Medium Priority:

• Relying on default providers in multi-region setups -- Use explicit providers per region. Set pulumi:disable-default-providers in config to enforce.
• Starting with functions instead of ComponentResource -- Migrating later requires aliases or resource recreation. Use components from the start.
• Not using dependsOn for non-obvious dependencies -- Pulumi infers dependencies from Input/Output wiring, but side effects (IAM propagation, DNS) need explicit ordering.
• Using deprecated transformations -- Use transforms instead. transforms also support modifying child resources of packaged components.
• Hardcoding region/account in resource args -- Use pulumi.Config and providers for environment-specific values.

Gotchas & Edge Cases:

• Auto-naming appends a random suffix -- never rely on exact physical resource names in external systems
• Pulumi does not refresh state by default -- use pulumi refresh to detect drift
• pulumi.secret() wraps a value so it's encrypted in state -- any derived Output is automatically secret too
• Output.apply() runs during pulumi up, not during preview for unknown values -- conditional logic based on unknown outputs may not evaluate during preview
• Component type tokens must follow pkg:module:Type format (e.g., myinfra:network:Vpc) to avoid conflicts
• Dynamic providers serialize the provider class -- closures over external state, functions, or DOM nodes will fail
• protect: true only prevents pulumi destroy deletion, not manual cloud console deletion
• Stack names in StackReference are fully qualified: org/project/stack

</red_flags>

---

<critical_reminders>

CRITICAL REMINDERS

All code must follow project conventions in CLAUDE.md

(You MUST pass { parent: this } to ALL child resources inside a ComponentResource -- omitting it breaks the resource tree and state tracking)

(You MUST use pulumi.interpolate for string building with Outputs -- string concatenation silently produces [object Object])

(You MUST NEVER create resources inside .apply() -- they will not appear in pulumi preview and cause ordering issues)

(You MUST use Config.requireSecret() for sensitive values -- Config.require() stores values as plaintext in state)

(You MUST call this.registerOutputs() at the end of every ComponentResource constructor -- omitting it prevents output tracking)

Failure to follow these rules will cause broken state tracking, silent data exposure, and unpredictable deployment behavior.

</critical_reminders>