CircleCI OIDC

This repository contains constructs to communicate between CircleCI and AWS via an Open ID Connect (OIDC) provider. The process is described in this CircleCI blog post.

Security Benefits

By using the OpenID Connect provider, you can communicate with AWS from CircleCI without saving static credentials (e.g., AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY) in your CircleCI project settings or a context. Removing static credentials, especially in light of the early 2023 breach, is a best practice for security.

Quick Start

Install the package:

npm install @blimmer/cdk-circleci-oidc

or

yarn add @blimmer/cdk-circleci-oidc

Then, create the provider and role(s).

import { Stack, StackProps } from "aws-cdk-lib";
import { CircleCiOidcProvider, CircleCiOidcRole } from "@blimmer/cdk-circleci-oidc";
import { Construct } from "constructs";
import { ManagedPolicy, PolicyStatement } from "aws-cdk-lib/aws-iam";
import { Bucket } from "aws-cdk-lib/aws-s3";

export class CircleCiStack extends Stack {
  constructor(scope: Construct, id: string, props?: StackProps) {
    super(scope, id, props);

    // The provider is only created _once per AWS account_. It might make sense to define this in a separate stack
    // that defines more global resources. See below for how to use import the provider in stacks that don't define it.
    const provider = new CircleCiOidcProvider(this, "OidcProvider", {
      // Find your organization ID in the CircleCI dashboard under "Organization Settings"
      organizationId: "11111111-2222-3333-4444-555555555555",
    });

    const myCircleCiRole = new CircleCiOidcRole(this, "MyCircleCiRole", {
      provider,
      roleName: "MyCircleCiRole",

      // Pass some managed policies to the role
      managedPolicies: [ManagedPolicy.fromAwsManagedPolicyName("AmazonS3ReadOnlyAccess")],
    });

    // You can work with the CircleCI role like any other role
    myCircleCiRole.addToPolicy(
      new PolicyStatement({
        actions: ["s3:ListAllMyBuckets"],
        resources: ["*"],
      }),
    );

    // Including using `.grant` convenience methods
    const bucket = new Bucket(this, "MyBucket");
    bucket.grantRead(myCircleCiRole);
  }
}

Now, in your .circleci/config.yml file, you can use the AWS CLI Orb to assume your new role.

version: 2.1

orbs:
  aws-cli: circleci/aws-cli@4.1.0 # https://circleci.com/developer/orbs/orb/circleci/aws-cli

workflows:
  version: 2
  build:
    jobs:
      - oidc-job:
          context: oidc-assumption # You _must_ use a context, even if it doesn't contain any secrets (see https://circleci.com/docs/openid-connect-tokens/#openid-connect-id-token-availability)

jobs:
  oidc-job:
    docker:
      - image: cimg/base:stable
    steps:
      - checkout
      # https://circleci.com/developer/orbs/orb/circleci/aws-cli#commands-setup
      - aws-cli/setup:
          role_arn: "arn:aws:iam::123456789101:role/MyCircleCiRole"
      - run:
          name: List S3 Buckets
          command: aws s3 ls

Usage in Stacks that Don't Define the Provider

The CircleCiOidcProvider is only created once per account. You can use the CircleCiOidcProvider.fromOrganizationId method to import a previously created provider into any stack.

import { Stack, StackProps } from "aws-cdk-lib";
import { CircleCiOidcRole, CircleCiOidcProvider } from "@blimmer/cdk-circleci-oidc";
import { Construct } from "constructs";

export class MyStack extends Stack {
  constructor(scope: Construct, id: string, props?: StackProps) {
    super(scope, id, props);

    const myCircleCiRole = new CircleCiOidcRole(this, "MyCircleCiRole", {
      provider: CircleCiOidcProvider.fromOrganizationId(this, "11111111-2222-3333-4444-555555555555"),
      roleName: "MyCircleCiRole",
    });
  }
}

Usage

For detailed API docs, see API.md.

Python

This package is available for Python as cdk-circleci-oidc.

pip install cdk-circleci-oidc

Upgrading Between Major Versions

The API can be expected to change between major versions. Please consult the UPGRADING docs for for information.

Contributing

Contributions, issues, and feedback are welcome!