basic.js

// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

import { fileURLToPath } from "node:url";

// snippet-start:[javascript.iam_scenarios.iam_basics]
import {
  CreateUserCommand,
  GetUserCommand,
  CreateAccessKeyCommand,
  CreatePolicyCommand,
  CreateRoleCommand,
  AttachRolePolicyCommand,
  DeleteAccessKeyCommand,
  DeleteUserCommand,
  DeleteRoleCommand,
  DeletePolicyCommand,
  DetachRolePolicyCommand,
  IAMClient,
} from "@aws-sdk/client-iam";
import { ListBucketsCommand, S3Client } from "@aws-sdk/client-s3";
import { AssumeRoleCommand, STSClient } from "@aws-sdk/client-sts";
import { retry } from "@aws-doc-sdk-examples/lib/utils/util-timers.js";
import { ScenarioInput } from "@aws-doc-sdk-examples/lib/scenario/index.js";

// Set the parameters.
const iamClient = new IAMClient({});
const userName = "iam_basic_test_username";
const policyName = "iam_basic_test_policy";
const roleName = "iam_basic_test_role";

/**
 * Create a new IAM user. If the user already exists, give
 * the option to delete and re-create it.
 * @param {string} name
 */
export const createUser = async (name, confirmAll = false) => {
  try {
    const { User } = await iamClient.send(
      new GetUserCommand({ UserName: name }),
    );
    const input = new ScenarioInput(
      "deleteUser",
      "Do you want to delete and remake this user?",
      { type: "confirm" },
    );
    const deleteUser = await input.handle({}, { confirmAll });
    // If the user exists, and you want to delete it, delete the user
    // and then create it again.
    if (deleteUser) {
      await iamClient.send(new DeleteUserCommand({ UserName: User.UserName }));
      await iamClient.send(new CreateUserCommand({ UserName: name }));
    } else {
      console.warn(
        `${name} already exists. The scenario may not work as expected.`,
      );
      return User;
    }
  } catch (caught) {
    // If there is no user by that name, create one.
    if (caught instanceof Error && caught.name === "NoSuchEntityException") {
      const { User } = await iamClient.send(
        new CreateUserCommand({ UserName: name }),
      );
      return User;
    }
    throw caught;
  }
};

export const main = async (confirmAll = false) => {
  // Create a user. The user has no permissions by default.
  const User = await createUser(userName, confirmAll);

  if (!User) {
    throw new Error("User not created");
  }

  // Create an access key. This key is used to authenticate the new user to
  // Amazon Simple Storage Service (Amazon S3) and AWS Security Token Service (AWS STS).
  // It's not best practice to use access keys. For more information, see https://aws.amazon.com/iam/resources/best-practices/.
  const createAccessKeyResponse = await iamClient.send(
    new CreateAccessKeyCommand({ UserName: userName }),
  );

  if (
    !createAccessKeyResponse.AccessKey?.AccessKeyId ||
    !createAccessKeyResponse.AccessKey?.SecretAccessKey
  ) {
    throw new Error("Access key not created");
  }

  const {
    AccessKey: { AccessKeyId, SecretAccessKey },
  } = createAccessKeyResponse;

  let s3Client = new S3Client({
    credentials: {
      accessKeyId: AccessKeyId,
      secretAccessKey: SecretAccessKey,
    },
  });

  // Retry the list buckets operation until it succeeds. InvalidAccessKeyId is
  // thrown while the user and access keys are still stabilizing.
  await retry({ intervalInMs: 1000, maxRetries: 300 }, async () => {
    try {
      return await listBuckets(s3Client);
    } catch (err) {
      if (err instanceof Error && err.name === "InvalidAccessKeyId") {
        throw err;
      }
    }
  });

  // Retry the create role operation until it succeeds. A MalformedPolicyDocument error
  // is thrown while the user and access keys are still stabilizing.
  const { Role } = await retry(
    {
      intervalInMs: 2000,
      maxRetries: 60,
    },
    () =>
      iamClient.send(
        new CreateRoleCommand({
          AssumeRolePolicyDocument: JSON.stringify({
            Version: "2012-10-17",
            Statement: [
              {
                Effect: "Allow",
                Principal: {
                  // Allow the previously created user to assume this role.
                  AWS: User.Arn,
                },
                Action: "sts:AssumeRole",
              },
            ],
          }),
          RoleName: roleName,
        }),
      ),
  );

  if (!Role) {
    throw new Error("Role not created");
  }

  // Create a policy that allows the user to list S3 buckets.
  const { Policy: listBucketPolicy } = await iamClient.send(
    new CreatePolicyCommand({
      PolicyDocument: JSON.stringify({
        Version: "2012-10-17",
        Statement: [
          {
            Effect: "Allow",
            Action: ["s3:ListAllMyBuckets"],
            Resource: "*",
          },
        ],
      }),
      PolicyName: policyName,
    }),
  );

  if (!listBucketPolicy) {
    throw new Error("Policy not created");
  }

  // Attach the policy granting the 's3:ListAllMyBuckets' action to the role.
  await iamClient.send(
    new AttachRolePolicyCommand({
      PolicyArn: listBucketPolicy.Arn,
      RoleName: Role.RoleName,
    }),
  );

  // Assume the role.
  const stsClient = new STSClient({
    credentials: {
      accessKeyId: AccessKeyId,
      secretAccessKey: SecretAccessKey,
    },
  });

  // Retry the assume role operation until it succeeds.
  const { Credentials } = await retry(
    { intervalInMs: 2000, maxRetries: 60 },
    () =>
      stsClient.send(
        new AssumeRoleCommand({
          RoleArn: Role.Arn,
          RoleSessionName: `iamBasicScenarioSession-${Math.floor(
            Math.random() * 1000000,
          )}`,
          DurationSeconds: 900,
        }),
      ),
  );

  if (!Credentials?.AccessKeyId || !Credentials?.SecretAccessKey) {
    throw new Error("Credentials not created");
  }

  s3Client = new S3Client({
    credentials: {
      accessKeyId: Credentials.AccessKeyId,
      secretAccessKey: Credentials.SecretAccessKey,
      sessionToken: Credentials.SessionToken,
    },
  });

  // List the S3 buckets again.
  // Retry the list buckets operation until it succeeds. AccessDenied might
  // be thrown while the role policy is still stabilizing.
  await retry({ intervalInMs: 2000, maxRetries: 120 }, () =>
    listBuckets(s3Client),
  );

  // Clean up.
  await iamClient.send(
    new DetachRolePolicyCommand({
      PolicyArn: listBucketPolicy.Arn,
      RoleName: Role.RoleName,
    }),
  );

  await iamClient.send(
    new DeletePolicyCommand({
      PolicyArn: listBucketPolicy.Arn,
    }),
  );

  await iamClient.send(
    new DeleteRoleCommand({
      RoleName: Role.RoleName,
    }),
  );

  await iamClient.send(
    new DeleteAccessKeyCommand({
      UserName: userName,
      AccessKeyId,
    }),
  );

  await iamClient.send(
    new DeleteUserCommand({
      UserName: userName,
    }),
  );
};

/**
 *
 * @param {S3Client} s3Client
 */
const listBuckets = async (s3Client) => {
  const { Buckets } = await s3Client.send(new ListBucketsCommand({}));

  if (!Buckets) {
    throw new Error("Buckets not listed");
  }

  console.log(Buckets.map((bucket) => bucket.Name).join("\n"));
};

// snippet-end:[javascript.iam_scenarios.iam_basics]

// Invoke main function if this file was run directly.
if (process.argv[1] === fileURLToPath(import.meta.url)) {
  main();
}