Archive Notice

AWS has now added this functionality into their GitHub action. It is recommended you use that for the latest features.

Github Actions Assume Role

This github action is to allow for assuming role via the steps provided in AWS federation comes to GitHub Actions. The idea is to abstract away some of the process from the user, such that they only need to have the role id available.

Configuring the role

First you will need to configure the role to be assumed. Here is an example cloudformation template taken from the blog post.

Parameters:
  RepoName:
    Type: String
    Default: aidansteele/aws-federation-github-actions
  GithubOrg:
    Type: String
    Default: aidansteele

Resources:
  Role:
    Type: AWS::IAM::Role
    Properties:
      RoleName: ExampleGithubRole
      ManagedPolicyArns: [arn:aws:iam::aws:policy/ReadOnlyAccess]
      AssumeRolePolicyDocument:
        Statement:
          - Effect: Allow
            Action: sts:AssumeRoleWithWebIdentity
            Principal:
              Federated: !Ref GithubOidc
            Condition:
              StringLike:
                token.actions.githubusercontent.com:sub: !Sub repo:${RepoName}:*

  GithubOidc:
    Type: AWS::IAM::OIDCProvider
    Properties:
      Url: https://token.actions.githubusercontent.com
      ClientIdList: 
        - !Sub https://github.com/${GithubOrg}
      ThumbprintList: [a031c46782e6e6c662c2c87c76da9aa62ccabd8e]

Outputs:
  Role:
    Value: !GetAtt Role.Arn  

Setup the action

Inputs

role_arn

Required arn of which you want to assume.

Example usage

...
    permissions:
      id-token: write
      contents: read
    steps:
      - uses: danquack/aws-assume-role@main
        with:
          role_arn: arn:aws:iam::123456789012:role/ExampleGithubRole
      - run: aws sts get-caller-identity