A ComponentResource groups related infrastructure resources into a reusable, logical unit. Components make infrastructure easier to understand, reuse, and maintain. Components appear as a single node with children nested underneath in pulumi preview/pulumi up output and in the Pulumi Cloud console.

This skill covers the full component authoring lifecycle. For general Pulumi coding patterns (Output handling, secrets, aliases, preview workflows), use the pulumi-best-practices skill instead.

When to Use This Skill

Invoke this skill when:

Creating a new ComponentResource class
Designing the args interface for a component
Making a component consumable from multiple Pulumi languages
Publishing or distributing a component package
Refactoring inline resources into a reusable component
Debugging component behavior (missing outputs, stuck creating, children at wrong level)

Component Anatomy

Every component has four required elements:

Extend ComponentResource and call super() with a type URN
Accept standard parameters: name, args, and ComponentResourceOptions
Set parent: this on all child resources
Call registerOutputs() at the end of the constructor

TypeScript

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

interface StaticSiteArgs {
    indexDocument?: pulumi.Input<string>;
    errorDocument?: pulumi.Input<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) {
        // 1. Call super with type URN: <package>:<module>:<type>
        super("myorg:index:StaticSite", name, {}, opts);

        // 2. Create child resources with parent: this
        const bucket = new aws.s3.Bucket(`${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 });

        // 3. Expose outputs as class properties
        this.bucketName = bucket.id;
        this.websiteUrl = website.websiteEndpoint;

        // 4. Register outputs -- always the last line
        this.registerOutputs({
            bucketName: this.bucketName,
            websiteUrl: this.websiteUrl,
        });
    }
}

// Usage
const site = new StaticSite("marketing", {
    indexDocument: "index.html",
});
export const url = site.websiteUrl;

Python

import pulumi
import pulumi_aws as aws

class StaticSiteArgs:
    def __init__(self,
                 index_document: pulumi.Input[str] = "index.html",
                 error_document: pulumi.Input[str] = "error.html"):
        self.index_document = index_document
        self.error_document = error_document

class StaticSite(pulumi.ComponentResource):
    bucket_name: pulumi.Output[str]
    website_url: pulumi.Output[str]

    def __init__(self, name: str, args: StaticSiteArgs,
                 opts: pulumi.ResourceOptions = None):
        super().__init__("myorg:index:StaticSite", name, None, opts)

        bucket = aws.s3.Bucket(f"{name}-bucket",
            opts=pulumi.ResourceOptions(parent=self))

        website = aws.s3.BucketWebsiteConfigurationV2(f"{name}-website",
            bucket=bucket.id,
            index_document=aws.s3.BucketWebsiteConfigurationV2IndexDocumentArgs(
                suffix=args.index_document,
            ),
            error_document=aws.s3.BucketWebsiteConfigurationV2ErrorDocumentArgs(
                key=args.error_document,
            ),
            opts=pulumi.ResourceOptions(parent=self))

        self.bucket_name = bucket.id
        self.website_url = website.website_endpoint

        self.register_outputs({
            "bucket_name": self.bucket_name,
            "website_url": self.website_url,
        })

site = StaticSite("marketing", StaticSiteArgs())
pulumi.export("url", site.website_url)

Type URN Format

The first argument to super() is the type URN: <package>:<module>:<type>.

| package | Organization or package name | myorg, acme, pkg

| module | Usually index | index

| type | PascalCase class name | StaticSite, VpcNetwork

Full examples: myorg:index:StaticSite, acme:index:KubernetesCluster

registerOutputs Is Required

Why: Without registerOutputs(), the component appears stuck in a "creating" state in the Pulumi console and outputs are not persisted to state.

Wrong:

class MyComponent extends pulumi.ComponentResource {
    public readonly url: pulumi.Output<string>;

    constructor(name: string, args: MyArgs, opts?: pulumi.ComponentResourceOptions) {
        super("myorg:index:MyComponent", name, {}, opts);
        const bucket = new aws.s3.Bucket(`${name}-bucket`, {}, { parent: this });
        this.url = bucket.bucketRegionalDomainName;
        // Missing registerOutputs -- component stuck "creating"
    }
}

Right:

class MyComponent extends pulumi.ComponentResource {
    public readonly url: pulumi.Output<string>;

    constructor(name: string, args: MyArgs, opts?: pulumi.ComponentResourceOptions) {
        super("myorg:index:MyComponent", name, {}, opts);
        const bucket = new aws.s3.Bucket(`${name}-bucket`, {}, { parent: this });
        this.url = bucket.bucketRegionalDomainName;

        this.registerOutputs({ url: this.url });
    }
}

Derive Child Names from the Component Name

Why: Hardcoded child names cause collisions when the component is instantiated multiple times.

Wrong:

// Collides if two instances of this component exist
const bucket = new aws.s3.Bucket("my-bucket", {}, { parent: this });

Right:

// Unique per component instance
const bucket = new aws.s3.Bucket(`${name}-bucket`, {}, { parent: this });

Designing the Args Interface

The args interface is the most impactful design decision. It defines what consumers can configure and how composable the component is.

Wrap Properties in Input

Why: Input<T> accepts both plain values and Output<T> from other resources. Without it, consumers must unwrap outputs manually with .apply().

Wrong:

interface WebServiceArgs {
    port: number;            // Forces consumers to unwrap Outputs
    vpcId: string;           // Cannot accept vpc.id directly
}

Right:

interface WebServiceArgs {
    port: pulumi.Input<number>;     // Accepts 8080 or someOutput
    vpcId: pulumi.Input<string>;    // Accepts "vpc-123" or vpc.id
}

Keep Structures Flat

Avoid deeply nested arg objects. Flat interfaces are easier to use and evolve.

// Prefer flat
interface DatabaseArgs {
    instanceClass: pulumi.Input<string>;
    storageGb: pulumi.Input<number>;
    enableBackups?: pulumi.Input<boolean>;
    backupRetentionDays?: pulumi.Input<number>;
}

// Avoid deep nesting
interface DatabaseArgs {
    instance: {
        compute: { class: pulumi.Input<string> };
        storage: { sizeGb: pulumi.Input<number> };
    };
    backup: {
        config: { enabled: pulumi.Input<boolean>; retention: pulumi.Input<number> };
    };
}

No Union Types

Union types break multi-language SDK generation. Python, Go, and C# cannot represent string | number.

Wrong:

interface MyArgs {
    port: pulumi.Input<string | number>;  // Fails in Python, Go, C#
}

Right:

interface MyArgs {
    port: pulumi.Input<number>;  // Single type, works everywhere
}

If you need to accept multiple forms, use separate optional properties:

interface StorageArgs {
    sizeGb?: pulumi.Input<number>;      // Specify size in GB
    sizeMb?: pulumi.Input<number>;      // Or specify size in MB
}

No Functions or Callbacks

Functions cannot be serialized across language boundaries.

Wrong:

interface MyArgs {
    nameTransform: (name: string) => string;  // Cannot serialize
}

Right:

interface MyArgs {
    namePrefix?: pulumi.Input<string>;   // Configuration instead of callback
    nameSuffix?: pulumi.Input<string>;
}

Use Defaults for Optional Properties

Set sensible defaults inside the constructor so consumers only configure what they need:

interface SecureBucketArgs {
    enableVersioning?: pulumi.Input<boolean>;   // Defaults to true
    enableEncryption?: pulumi.Input<boolean>;   // Defaults to true
    blockPublicAccess?: pulumi.Input<boolean>;  // Defaults to true
}

class SecureBucket extends pulumi.ComponentResource {
    constructor(name: string, args: SecureBucketArgs, opts?: pulumi.ComponentResourceOptions) {
        super("myorg:index:SecureBucket", name, {}, opts);

        const enableVersioning = args.enableVersioning ?? true;
        const enableEncryption = args.enableEncryption ?? true;
        const blockPublicAccess = args.blockPublicAccess ?? true;

        // Apply defaults...
    }
}

// Consumer only overrides what they need
const bucket = new SecureBucket("data", { enableVersioning: false });

Exposing Outputs

Expose Only What Consumers Need

Components often create many internal resources. Expose only the values consumers need, not every internal resource.

Wrong:

class Database extends pulumi.ComponentResource {
    // Exposes everything -- consumers see implementation details
    public readonly cluster: aws.rds.Cluster;
    public readonly primaryInstance: aws.rds.ClusterInstance;
    public readonly replicaInstance: aws.rds.ClusterInstance;
    public readonly subnetGroup: aws.rds.SubnetGroup;
    public readonly securityGroup: aws.ec2.SecurityGroup;
    public readonly parameterGroup: aws.rds.ClusterParameterGroup;
    // ...
}

Right:

class Database extends pulumi.ComponentResource {
    // Exposes only what consumers need
    public readonly endpoint: pulumi.Output<string>;
    public readonly port: pulumi.Output<number>;
    public readonly securityGroupId: pulumi.Output<string>;

    constructor(name: string, args: DatabaseArgs, opts?: pulumi.ComponentResourceOptions) {
        super("myorg:index:Database", name, {}, opts);

        const sg = new aws.ec2.SecurityGroup(`${name}-sg`, { /* ... */ }, { parent: this });
        const cluster = new aws.rds.Cluster(`${name}-cluster`, { /* ... */ }, { parent: this });

        this.endpoint = cluster.endpoint;
        this.port = cluster.port;
        this.securityGroupId = sg.id;

        this.registerOutputs({
            endpoint: this.endpoint,
            port: this.port,
            securityGroupId: this.securityGroupId,
        });
    }
}

Derive Composite Outputs

Use pulumi.interpolate or pulumi.concat to build derived values:

this.connectionString = pulumi.interpolate`postgresql://${args.username}:${args.password}@${cluster.endpoint}:${cluster.port}/${args.databaseName}`;

this.registerOutputs({ connectionString: this.connectionString });

Component Design Patterns

Sensible Defaults with Override

Encode best practices as defaults. Allow consumers to override when they have specific requirements.

interface SecureBucketArgs {
    enableVersioning?: pulumi.Input<boolean>;
    enableEncryption?: pulumi.Input<boolean>;
    blockPublicAccess?: pulumi.Input<boolean>;
    tags?: pulumi.Input<Record<string, pulumi.Input<string>>>;
}

class SecureBucket extends pulumi.ComponentResource {
    public readonly bucketId: pulumi.Output<string>;
    public readonly arn: pulumi.Output<string>;

    constructor(name: string, args: SecureBucketArgs = {}, opts?: pulumi.ComponentResourceOptions) {
        super("myorg:index:SecureBucket", name, {}, opts);

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

        // Versioning on by default
        if (args.enableVersioning !== false) {
            new aws.s3.BucketVersioningV2(`${name}-versioning`, {
                bucket: bucket.id,
                versioningConfiguration: { status: "Enabled" },
            }, { parent: this });
        }

        // Encryption on by default
        if (args.enableEncryption !== false) {
            new aws.s3.BucketServerSideEncryptionConfigurationV2(`${name}-encryption`, {
                bucket: bucket.id,
                rules: [{ applyServerSideEncryptionByDefault: { sseAlgorithm: "AES256" } }],
            }, { parent: this });
        }

        // Public access blocked by default
        if (args.blockPublicAccess !== false) {
            new aws.s3.BucketPublicAccessBlock(`${name}-public-access`, {
                bucket: bucket.id,
                blockPublicAcls: true,
                blockPublicPolicy: true,
                ignorePublicAcls: true,
                restrictPublicBuckets: true,
            }, { parent: this });
        }

        this.bucketId = bucket.id;
        this.arn = bucket.arn;
        this.registerOutputs({ bucketId: this.bucketId, arn: this.arn });
    }
}

Conditional Resource Creation

Use optional args to gate creation of sub-resources:

interface WebServiceArgs {
    image: pulumi.Input<string>;
    port: pulumi.Input<number>;
    enableMonitoring?: pulumi.Input<boolean>;
    alarmEmail?: pulumi.Input<string>;
}

class WebService extends pulumi.ComponentResource {
    constructor(name: string, args: WebServiceArgs, opts?: pulumi.ComponentResourceOptions) {
        super("myorg:index:WebService", name, {}, opts);

        const service = new aws.ecs.Service(`${name}-service`, {
            // ...service config...
        }, { parent: this });

        // Only create alarm infrastructure when monitoring is enabled
        if (args.enableMonitoring) {
            const topic = new aws.sns.Topic(`${name}-alerts`, {}, { parent: this });

            if (args.alarmEmail) {
                new aws.sns.TopicSubscription(`${name}-alert-email`, {
                    topic: topic.arn,
                    protocol: "email",
                    endpoint: args.alarmEmail,
                }, { parent: this });
            }

            new aws.cloudwatch.MetricAlarm(`${name}-cpu-alarm`, {
                // ...alarm config referencing service...
                alarmActions: [topic.arn],
            }, { parent: this });
        }

        this.registerOutputs({});
    }
}

Composition

Build higher-level components from lower-level ones. Each level manages a single concern.

// Lower-level component
class VpcNetwork extends pulumi.ComponentResource {
    public readonly vpcId: pulumi.Output<string>;
    public readonly publicSubnetIds: pulumi.Output<string>[];
    public readonly privateSubnetIds: pulumi.Output<string>[];

    constructor(name: string, args: VpcNetworkArgs, opts?: pulumi.ComponentResourceOptions) {
        super("myorg:index:VpcNetwork", name, {}, opts);
        // ...create VPC, subnets, route tables...
        this.registerOutputs({ vpcId: this.vpcId });
    }
}

// Higher-level component that uses VpcNetwork
class Platform extends pulumi.ComponentResource {
    public readonly kubeconfig: pulumi.Output<string>;

    constructor(name: string, args: PlatformArgs, opts?: pulumi.ComponentResourceOptions) {
        super("myorg:index:Platform", name, {}, opts);

        // Compose lower-level components
        const network = new VpcNetwork(`${name}-network`, {
            cidrBlock: args.cidrBlock,
        }, { parent: this });

        const cluster = new aws.eks.Cluster(`${name}-cluster`, {
            vpcConfig: {
                subnetIds: network.privateSubnetIds,
            },
        }, { parent: this });

        this.kubeconfig = cluster.kubeconfig;
        this.registerOutputs({ kubeconfig: this.kubeconfig });
    }
}

Provider Passthrough

Accept explicit providers for multi-region or multi-account deployments. ComponentResourceOptions carries provider configuration to children automatically:

// Consumer passes a provider for a different region
const usWest = new aws.Provider("us-west", { region: "us-west-2" });
const site = new StaticSite("west-site", { indexDocument: "index.html" }, {
    providers: [usWest],
});

Children with { parent: this } automatically inherit the provider. No extra code is needed inside the component.

Multi-Language Components

If your component will be consumed from multiple Pulumi languages (TypeScript, Python, Go, C#, Java, YAML), package it as a multi-language component.

Do You Need Multi-Language?

Ask: "Will anyone consume this component from a different language than it was authored in?"

Single-language component (no packaging needed):

Your team uses one language and the component stays within that codebase
The component is internal to a single project or monorepo
No PulumiPlugin.yaml needed -- just import the class directly

Multi-language component (packaging required):

Other teams consume your component in different languages
Platform teams building abstractions for developers who choose their own language
YAML consumers need access -- even if you author in TypeScript, YAML programs require multi-language packaging to use your component
Building a shared component library for your organization
Publishing to the Pulumi private registry or public registry is a common reason, but not required for multi-language support

Common mistake: A TypeScript platform team builds components only their TypeScript users can consume. If application developers use Python or YAML, those components are invisible to them without multi-language packaging.

Setup

Create a PulumiPlugin.yaml in the component directory to declare the runtime:

runtime: nodejs

Or for Python:

runtime: python

Serialization Constraints

For multi-language compatibility, args must be serializable. These constraints apply regardless of the authoring language:

| string, number, boolean | Union types (string | number)

| Input<T> wrappers | Functions and callbacks

| Arrays and maps of primitives | Complex nested generics

| Enums Platform-specific types<

pulumi-component

安装

When to Use This Skill

Component Anatomy

TypeScript

Python

Type URN Format

registerOutputs Is Required

Derive Child Names from the Component Name

Designing the Args Interface

Wrap Properties in Input

Keep Structures Flat

No Union Types

No Functions or Callbacks

Use Defaults for Optional Properties

Exposing Outputs

Expose Only What Consumers Need

Derive Composite Outputs

Component Design Patterns

Sensible Defaults with Override

Conditional Resource Creation

Composition

Provider Passthrough

Multi-Language Components

Do You Need Multi-Language?

Setup

Serialization Constraints