Terraform AWS GitHub Actions /w OIDC

This module configures AWS OIDC authentication with GitHub Actions, eliminating the need for static AWS IAM Access Keys when running Terraform within GitHub Actions.

GitHub Actions temporary AWS role credentials

We can use OpenID Connect within our workflows to authenticate with Amazon Web Services and get temporary session tokens to assume IAM roles.

sequenceDiagram
    autonumber
    participant A as Github Actions
    participant B as Oidc Provider
    participant C as AWS IAM

    A->>+B: Request JWT
    B->>-A: Issue signed JWT
    A->>+C: Request Access Token
    C-->>+B: Verify Token
    B-->>-C: Valid
    C->>-A: Issue Role Access Session Token

Usages

The module is at the time of writing super opinionated in how the AWS IAM Open ID Connect Provider is created. The only thing the user needs to be concerned about is the var.conditions. This needs to be set up the trust policy for the sub field, which is explained further here.

Multiple fields apart from the required sub field are supported for more granular permissions, a reference to the contents of the OIDC token can be found here.

Examples

Check out the examples/simple directory for using the module.

Resources

Name	Type
aws_iam_openid_connect_provider.github_actions	resource
aws_iam_role.github_actions	resource
aws_iam_role_policy_attachment.github_actions	resource
aws_iam_policy_document.github_actions	data source

Inputs

Name	Description	Type	Default	Required
conditions	Github conditions to apply to the AWS Role. E.g. from which org/repo/branch is it allowed to be run. Key is used as the JWT claim and value as the claim value.	map(string)	n/a	yes
policy_arn	List of ARNs of IAM policies to attach to IAM role.	list(string)	n/a	yes
role_name	The name of the AWS Role which will be used to run Github Actions.	string	n/a	yes
role_max_sessions_duration	Maximum session duration (in seconds) that you want to set for the specified role.	number	3600	no
role_permission_boundary	Boundary for the created role.	string	null	no

Outputs

Name	Description
openid_connect_provider	AWS OpenID Connected identity provider.
role	AWS Role created