README.md

awsswitch

This is a command to export the following credentials variables to switch a role with MFA.

• AWS_ACCESS_KEY_ID
• AWS_SECRET_ACCESS_KEY
• AWS_SESSION_TOKEN

Key features:

• Single binary
• Interoperable config with AWS CLI (~/.aws/config)
• Interoperable token cache with AWS CLI (~/.aws/cli/cache)

Getting Started

Install awsswitch.

# Homebrew (macOS)
brew install int128/awsswitch/awsswitch

# GitHub Releases
curl -LO https://github.com/int128/awsswitch/releases/download/v0.2.0/awsswitch_linux_amd64.zip
unzip awsswitch_linux_amd64.zip

# Go
go get github.com/int128/awsswitch

Set up your .aws/config to switch a role. For example,

[profile USERNAME]

[profile USERNAME_administrator]
mfa_serial = arn:aws:iam::1234567890:mfa/USERNAME
role_arn = arn:aws:iam::1234567890:role/AdministratorMFA
source_profile = USERNAME
duration_seconds = 43200

Run the command in your terminal.

% eval $(awsswitch --profile=USERNAME_administrator)
Enter MFA code:
you got a valid token until 2020-04-19 21:43:38 +0000 UTC

It will export the credentials variables. Now you can run tools such as AWS CLI and Terraform.

% aws s3 ls

% terraform apply

It attempts to read the token cache in ~/.aws/cli/cache. You do not need to enter a MFA code if the token is valid. This behavior is interoperable with AWS CLI.

How to set up the role switching

1. Set up a role

Create an IAM role to switch to. You need to set up a trusted relationship to an AWS account or IAM user.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "AWS": "arn:aws:iam::1234567890:root"
      },
      "Action": "sts:AssumeRole",
      "Condition": {
        "Bool": {
          "aws:MultiFactorAuthPresent": "true"
        }
      }
    }
  ]
}

2. Set up a user

Create an IAM user.

You need to set up an assume role. See document for more.

{
  "Version": "2012-10-17",
  "Statement": {
    "Effect": "Allow",
    "Action": "sts:AssumeRole",
    "Resource": "arn:aws:iam::1234567890:role/AdministratorMFA"
  }
}

Set your credentials to ~/.aws/credentials.

% aws configure --profile=USERNAME

Add a profile to .aws/config to switch to the role.

[profile USERNAME]

[profile USERNAME_administrator]
mfa_serial = arn:aws:iam::1234567890:mfa/USERNAME
role_arn = arn:aws:iam::1234567890:role/AdministratorMFA
source_profile = USERNAME
duration_seconds = 43200

Contributions

This is an open source software. Feel free to open issues and pull requests.