configure-aws-credentials/README.md

## Configure AWS Credentials for GitHub Actions
Configure your AWS credentials and region environment variables for use in other
GitHub Actions. This action implements the AWS SDK credential resolution chain
and exports environment variables for your other Actions to use. Environment
variable exports are detected by both the AWS SDKs and the AWS CLI for AWS API
calls.

### Recent updates
We've recently released a `v2` of this action that uses the Node 16 runtime by
default. You should update your action references to `v2`. We intend `v2` to be
the new default for this action and will no longer be providing updates to the
`v1` tag.

When migrating to `v2`, you don't have to consider any changes other than the node version.
There are no breaking changes between versions; As of release of v2, the node version is the only change.

As is usual for GitHub Actions, we provide release tags for you to reference in
your repository's workflow files. The `v2` tag is a moving tag that will always
apply to the lastest version 2 train release. We will also provide minor version
tags on every release, and create a `v3` tag when we are ready for a new major
release. If you had been following the development of this action so far, this
is a change to previous states release policy.

### Table of Contents
<!-- toc -->
- [Usage](#usage)
- [Credentials](#credentials)
- [Assuming a Role](#assuming-a-role)
    + [Session tagging](#session-tagging)
    + [Sample IAM Role Permissions](#sample-iam-role-cloudformation-template)
- [Self-Hosted Runners](#self-hosted-runners)
    + [Proxy Configuration](#proxy-configuration)
- [License Summary](#license-summary)
- [Security Disclosures](#security-disclosures)
<!-- tocstop -->

## Usage
We support four methods for fetching credentials from AWS, but we recommend that
you use GitHub's OIDC provider in conjunction with a configured AWS IAM
Identity Provider endpoint.

To to that, you would add the following step to your workflow:

```yaml
    - name: Configure AWS Credentials
      uses: aws-actions/configure-aws-credentials@v2
      with:
        role-to-assume: arn:aws:iam::123456789100:role/my-github-actions-role
        aws-region: us-east-2
```
This will cause the action to perform an `AssumeRoleWithWebIdentity` call and
return temporary security credentials for use by other actions. In order for
this to work, you'll need to preconfigure the IAM IdP in your AWS account
(see [Assuming a Role](#assuming-a-role) for details).

You can use this action with the AWS CLI available in
[GitHub's hosted virtual environments](https://help.github.com/en/actions/reference/software-installed-on-github-hosted-runners) or run this action multiple times
to use different AWS accounts, regions, or IAM roles in the same GitHub Actions
workflow. As an example, here is a complete workflow file that uploads artifacts
to Amazon S3.

```yaml
jobs:
  deploy:
    name: Upload to Amazon S3
    runs-on: ubuntu-latest
    # These permissions are needed to interact with GitHub's OIDC Token endpoint.
    permissions:
      id-token: write
      contents: read
    steps:
    - name: Checkout
      uses: actions/checkout@v3
    - name: Configure AWS credentials from Test account
      uses: aws-actions/configure-aws-credentials@v2
      with:
        role-to-assume: arn:aws:iam::111111111111:role/my-github-actions-role-test
        aws-region: us-east-1
    - name: Copy files to the test website with the AWS CLI
      run: |
        aws s3 sync . s3://my-s3-test-website-bucket
    - name: Configure AWS credentials from Production account
      uses: aws-actions/configure-aws-credentials@v2
      with:
        role-to-assume: arn:aws:iam::222222222222:role/my-github-actions-role-prod
        aws-region: us-west-2
    - name: Copy files to the production website with the AWS CLI
      run: |
        aws s3 sync . s3://my-s3-prod-website-bucket
```

See [action.yml](action.yml) for the full documentation for this action's inputs
and outputs.

## Credentials

We recommend following
[Amazon IAM best practices](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html)
for the AWS credentials used in GitHub Actions workflows, including:
  * Do not store credentials in your repository's code.
  * [Grant least privilege](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#grant-least-privilege) to the credentials used in GitHub Actions
  workflows. Grant only the permissions required to perform the actions in your
  GitHub Actions workflows.
  * [Monitor the activity](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#keep-a-log) of the credentials used in GitHub Actions workflows.

## Assuming a Role
There are four different supported ways to retrieve credentials. We recommend
using [GitHub's OIDC provider](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/configuring-openid-connect-in-amazon-web-services)
to get short-lived credentials needed for your actions. Specifying
`role-to-assume` **without** providing an `aws-access-key-id` or a
`web-identity-token-file` will signal to the action that you wish to use the
OIDC provider.

The following table describes which identity is used based on which values are supplied to the Action:

| **Identity Used**                                               | `aws-access-key-id` | `role-to-assume` | `web-identity-token-file` |
| --------------------------------------------------------------- | ------------------- | ---------------- | ------------------------- |
| [✅ Recommended] Assume Role directly using GitHub OIDC provider |                     | ✔                |                           |
| IAM User                                                        | ✔                   |                  |                           |
| Assume Role using IAM User credentials                          | ✔                   | ✔                |                           |
| Assume Role using WebIdentity Token File credentials            |                     | ✔                | ✔                         |

### Credential Lifetime
The default session duration is **1 hour** when using the OIDC provider to
directly assume an IAM Role or when an `aws-session-token` is directly provided.
The default session duration is **6 hours** when using an IAM User to assume an
IAM Role (by providing an `aws-access-key-id`, `aws-secret-access-key`, and a
`role-to-assume`) .

If you would like to adjust this you can pass a duration to `role-duration-seconds`, but the duration cannot exceed the maximum that was defined when the IAM Role was created.
The default session name is GitHubActions, and you can modify it by specifying the desired name in `role-session-name`.
The default audience is `sts.amazonaws.com` which you can replace by specifying the desired audience name in `audience`.

### Examples

#### AssumeRoleWithWebIdentity (recommended)
```yaml
    - name: Configure AWS Credentials
      uses: aws-actions/configure-aws-credentials@v2
      with:
        aws-region: us-east-2
        role-to-assume: arn:aws:iam::123456789100:role/my-github-actions-role
        role-session-name: MySessionName
```
In this example, the Action will load the OIDC token from the GitHub-provided environment variable and use it to assume the role `arn:aws:iam::123456789100:role/my-github-actions-role` with the session name `MySessionName`.

#### AssumeRole with static IAM credentials in repository secrets
```yaml
    - name: Configure AWS Credentials
      uses: aws-actions/configure-aws-credentials@v2
      with:
        aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
        aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
        aws-region: us-east-2
        role-to-assume: ${{ secrets.AWS_ROLE_TO_ASSUME }}
        role-external-id: ${{ secrets.AWS_ROLE_EXTERNAL_ID }}
        role-duration-seconds: 1200
        role-session-name: MySessionName
```
In this example, the secret `AWS_ROLE_TO_ASSUME` contains a string like `arn:aws:iam::123456789100:role/my-github-actions-role`.  To assume a role in the same account as the static credentials, you can simply specify the role name, like `role-to-assume: my-github-actions-role`.

#### AssumeRoleWithWebIdentity using a custom audience
```yaml
    - name: Configure AWS Credentials for Beta Customers
      uses: aws-actions/configure-aws-credentials@v2
      with:
        audience: beta-customers
        aws-region: us-east-3
        role-to-assume: arn:aws:iam::123456789100:role/my-github-actions-role
        role-session-name: MySessionName
```
In this example, the audience has been changed from the default to use a different audience name `beta-customers`. This can help ensure that the role can only affect those AWS accounts whose GitHub OIDC providers have explicitly opted in to the `beta-customers` label.

Changing the default audience may be necessary when using non-default [AWS partitions](https://docs.aws.amazon.com/general/latest/gr/aws-arns-and-namespaces.html).

#### AssumeRoleWithWebIdentity and disable secure Action outputs
```yaml
    - name: Configure AWS Credentials
      uses: aws-actions/configure-aws-credentials@v2
      with:
        aws-region: us-east-2
        role-to-assume: arn:aws:iam::123456789100:role/my-github-actions-role
        role-session-name: MySessionName
        mask-aws-account-id: false
```
In this example, account ID masking has been disabled. By default, the AWS
account ID will be obscured in the action's output. This may be helpful when
debugging action failures.

## Sample IAM OIDC CloudFormation Template
If you choose to use GitHub's OIDC provider, you must first set up federation
with the provider in as an IAM IdP. The GitHub OIDC provider only needs to be
created once per account (i.e. multiple IAM Roles that can be assumed by the
GitHub's OIDC can share a single OIDC Provider).

This CloudFormation template will configure the IdP for you.
```yaml
Parameters:
  GitHubOrg:
    Description: Name of GitHub organization/user (case sensitive)
    Type: String
  RepositoryName:
    Description: Name of GitHub repository (case sensitive)
    Type: String
  OIDCProviderArn:
    Description: Arn for the GitHub OIDC Provider.
    Default: ""
    Type: String
  OIDCAudience:
    Description: Audience supplied to configure-aws-credentials.
    Default: "sts.amazonaws.com"
    Type: String

Conditions:
  CreateOIDCProvider: !Equals 
    - !Ref OIDCProviderArn
    - ""

Resources:
  Role:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Statement:
          - Effect: Allow
            Action: sts:AssumeRoleWithWebIdentity
            Principal:
              Federated: !If 
                - CreateOIDCProvider
                - !Ref GithubOidc
                - !Ref OIDCProviderArn
            Condition:
              StringEquals:
                token.actions.githubusercontent.com:aud: !Ref OIDCAudience
              StringLike:
                token.actions.githubusercontent.com:sub: !Sub repo:${GitHubOrg}/${RepositoryName}:*

  GithubOidc:
    Type: AWS::IAM::OIDCProvider
    Condition: CreateOIDCProvider
    Properties:
      Url: https://token.actions.githubusercontent.com
      ClientIdList: 
        - sts.amazonaws.com
      ThumbprintList:
        - 6938fd4d98bab03faadb97b34396831e3780aea1

Outputs:
  Role:
    Value: !GetAtt Role.Arn 
```

To align with the Amazon IAM best practice of
[granting least privilege](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#grant-least-privilege), the assume role policy document should contain a
[`Condition`](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition.html) that specifies a subject allowed to assume the role. Without a subject
condition, any GitHub user or repository could potentially assume the role. The
subject can be scoped to a GitHub organization and repository as shown in the
CloudFormation template. Additional claim conditions can be added for higher
specificity as explained in the
[GitHub documentation](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/about-security-hardening-with-openid-connect).
Due to implementation details, not every OIDC claim is presently supported by
IAM.

For further information on OIDC and GitHub Actions, please see:

* [AWS docs: Creating OpenID Connect (OIDC) identity providers](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_providers_create_oidc.html)
* [AWS docs: IAM JSON policy elements: Condition](https://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements_condition.html)
* [GitHub docs: About security hardening with OpenID Connect](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/about-security-hardening-with-openid-connect)
* [GitHub docs: Configuring OpenID Connect in Amazon Web Services](https://docs.github.com/en/actions/deployment/security-hardening-your-deployments/configuring-openid-connect-in-amazon-web-services)
* [GitHub changelog: GitHub Actions: Secure cloud deployments with OpenID Connect](https://github.blog/changelog/2021-10-27-github-actions-secure-cloud-deployments-with-openid-connect/)

### Session tagging
The session will have the name "GitHubActions" and be tagged with the following
tags: (`GITHUB_` environment variable definitions can be
[found here](https://help.github.com/en/actions/automating-your-workflow-with-github-actions/using-environment-variables#default-environment-variables))

| Key        | Value             |
| ---------- | ----------------- |
| GitHub     | "Actions"         |
| Repository | GITHUB_REPOSITORY |
| Workflow   | GITHUB_WORKFLOW   |
| Action     | GITHUB_ACTION     |
| Actor      | GITHUB_ACTOR      |
| Branch     | GITHUB_REF        |
| Commit     | GITHUB_SHA        |

_Note: all tag values must conform to
[the requirements](https://docs.aws.amazon.com/STS/latest/APIReference/API_Tag.html).
Particularly, `GITHUB_WORKFLOW` will be truncated if it's too long. If
`GITHUB_ACTOR` or `GITHUB_WORKFLOW` contain invalid characters, the characters
will be replaced with an '*'._

The action will use session tagging by default during role assumption. 
Note that for WebIdentity role assumption, the session tags have to be included
in the encoded WebIdentity token. This means that Tags can only be supplied by
the OIDC provider and not set during the AssumeRoleWithWebIdentity API call
within the Action. You can skip this session tagging by providing
`role-skip-session-tagging` as true in the action's inputs:
```yaml
      uses: aws-actions/configure-aws-credentials@v2
      with:
        role-skip-session-tagging: true
```

## Self-Hosted Runners

If you run your GitHub Actions in a
[self-hosted runner](https://help.github.com/en/actions/hosting-your-own-runners/about-self-hosted-runners) that already has access to AWS credentials, such as
an EC2 instance, then you do not need to provide IAM user access key credentials
to this action. We will use the standard AWS JavaScript SDK credential
resolution methods to find your credentials, so if the AWS JS SDK can
authenticate on your runner, this Action will as well.

If no access key credentials are given in the action inputs, this action will
use credentials from the runner environment using the
[default methods for the AWS SDK for Javascript](https://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/setting-credentials-node.html).

You can use this action to simply configure the region and account ID in the
environment, and then use the runner's credentials for all AWS API calls made by
your Actions workflow:
```yaml
uses: aws-actions/configure-aws-credentials@v2
with:
  aws-region: us-east-2
```
In this case, your runner's credentials must have permissions to call any AWS
APIs called by your Actions workflow.

Or, you can use this action to assume a role, and then use the role credentials
for all AWS API calls made by your Actions workflow:
```yaml
uses: aws-actions/configure-aws-credentials@v2
with:
  aws-region: us-east-2
  role-to-assume: my-github-actions-role
```
In this case, your runner's credentials must have permissions to assume the
role.

You can also assume a role using a web identity token file, such as if using
[Amazon EKS IRSA](https://docs.aws.amazon.com/eks/latest/userguide/iam-roles-for-service-accounts-technical-overview.html). Pods running in EKS
worker nodes that do not run as root can use this file to assume a role with a
web identity.

### Proxy Configuration

If you run in self-hosted environments and in secured environment where you need
use a specific proxy you can set it in the action manually.

Additionally this action will always consider already configured proxy in the
environment.

Manually configured proxy:
```yaml
uses: aws-actions/configure-aws-credentials@v2
with:
  aws-region: us-east-2
  role-to-assume: my-github-actions-role
  http-proxy: "http://companydomain.com:3128"
```

Proxy configured in the environment variable:
```bash
# Your environment configuration
HTTP_PROXY="http://companydomain.com:3128"
```

The action will read the underlying proxy configuration from the environment and
you don't need to configure it in the action.

### Use with the AWS CLI
This workflow does _not_ install the [AWS CLI](https://aws.amazon.com/cli/)
into your environment. Self-hosted runners that intend to run this action prior
to executing `aws` commands need to have the AWS CLI
[installed](https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-install.html)
if it's not already present. 
Most [GitHub hosted runner environments](https://github.com/actions/virtual-environments)
should include the AWS CLI by default.
 
## License Summary
This code is made available under the MIT license.

## Security Disclosures
If you would like to report a potential security issue in this project, please do not create a GitHub issue.  Instead, please follow the instructions [here](https://aws.amazon.com/security/vulnerability-reporting/) or [email AWS security directly](mailto:aws-security@amazon.com).