format-aws-credential.sh

#!/bin/bash
#
# DESCRIPTION
# utility to aid in the setup of temporary AWS assumed role credentials
#
# USAGE
# pipe the output of aws sts assume-role to this script and redirect the output
# to append the temporary credentials to your $HOME/.aws/credentials
#
# you may supply a profile name as an argument. if you do not, then one is generated
# for you from the current time.
#
# EXAMPLE
# aws sts assume-role --role-arn arn:aws:iam::000987654321:role/some-assumed-role \
#                     --role-session-name iam-pw-reset-aws-cli \
#                     --serial-number arn:aws:iam::123456789000:mfa/YourName \
#                     --token-code 123456
#                     --profile some-profile | format-aws-credential.sh assumed-profile-name >> ~/.aws/credentials

STDIN=$(cat)

ACCESS_KEY=$(echo $STDIN | jq -r '.Credentials.AccessKeyId')
SECRET_KEY=$(echo $STDIN | jq -r '.Credentials.SecretAccessKey')
SESSION=$(echo $STDIN | jq -r '.Credentials.SessionToken')

DEFAULT_PROFILE=$(date +"temp-%Y%m%d%H%M%S")

PROFILE="${1:-$DEFAULT_PROFILE}"

cat <<-EOF

[$PROFILE]
aws_access_key_id = $ACCESS_KEY
aws_secret_access_key = $SECRET_KEY
aws_session_token = $SESSION

EOF