Skip to content

Latest commit

 

History

History
245 lines (198 loc) · 11.4 KB

README.md

File metadata and controls

245 lines (198 loc) · 11.4 KB
Raw

"Configure AWS Credentials" Action For GitHub Actions

Configure AWS credential and region environment variables for use in other GitHub Actions. The environment variables will be detected by both the AWS SDKs and the AWS CLI to determine the credentials and region to use for AWS API calls.

Table of Contents

Usage

Add the following step to your workflow:

    - name: Configure AWS Credentials
      uses: aws-actions/configure-aws-credentials@v1
      with:
        role-to-assume: arn:aws:iam::123456789100:role/my-github-actions-role
        aws-region: us-east-2

For example, you can use this action with the AWS CLI available in GitHub's hosted virtual environments. You can also run this action multiple times to use different AWS accounts, regions, or IAM roles in the same GitHub Actions workflow job.

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@v2

    - name: Configure AWS credentials from Test account
      uses: aws-actions/configure-aws-credentials@v1
      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@v1
      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 for the full documentation for this action's inputs and outputs.

Credentials

We recommend following Amazon IAM best practices for the AWS credentials used in GitHub Actions workflows, including:

  • Do not store credentials in your repository's code.
  • 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 of the credentials used in GitHub Actions workflows.

Assuming a Role

We recommend using GitHub's OIDC provider 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 default session duration is 1 hour when using the OIDC provider to directly assume an IAM Role. 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 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 ✔ ✔

Examples

    - name: Configure AWS Credentials
      uses: aws-actions/configure-aws-credentials@v1
      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.

    - name: Configure AWS Credentials
      uses: aws-actions/configure-aws-credentials@v1
      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.

Sample IAM Role CloudFormation Template

Parameters:
  GitHubOrg:
    Type: String
  RepositoryName:
    Type: String
  OIDCProviderArn:
    Description: Arn for the GitHub OIDC Provider.
    Default: ""
    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:
              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:
        - a031c46782e6e6c662c2c87c76da9aa62ccabd8e

Outputs:
  Role:
    Value: !GetAtt Role.Arn

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)

Session tagging

The session will have the name "GitHubActions" and be tagged with the following tags: (GITHUB_ environment variable definitions can be found here)

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. 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:

      uses: aws-actions/configure-aws-credentials@v1
      with:
        role-skip-session-tagging: true

Self-Hosted Runners

If you run your GitHub Actions in a self-hosted runner 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.

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.

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:

uses: aws-actions/configure-aws-credentials@v1
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:

uses: aws-actions/configure-aws-credentials@v1
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. Pods running in EKS worker nodes that do not run as root can use this file to assume a role with a web identity.

You can configure your workflow as follows in order to use this file:

uses: aws-actions/configure-aws-credentials@v1
with:
  aws-region: us-east-2
  role-to-assume: my-github-actions-role
  web-identity-token-file: /var/run/secrets/eks.amazonaws.com/serviceaccount/token

Use with the AWS CLI

This workflow does not install the AWS 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 if it's not already present. Most GitHub hosted runner 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 or email AWS security directly.