Assume a AWS STS role using the AWS credentials environment variables

aws-assume-role-env.sh

#!/bin/bash
set -ue

readonly roleArn="$1"
readonly durationSeconds="3600" # 1 hours
readonly roleSessionName="$USER-local"

# Use default profile to log in
unset AWS_ACCESS_KEY_ID
unset AWS_SECRET_ACCESS_KEY
unset AWS_SESSION_TOKEN
unset AWS_PROFILE

readonly creds="$(aws sts assume-role --role-arn $roleArn --role-session-name $roleSessionName --duration-seconds $durationSeconds --output json)"
readonly accessKeyId=$(echo "$creds" | jq -r .Credentials.AccessKeyId)
readonly secretAccessKey=$(echo "$creds" | jq -r .Credentials.SecretAccessKey)
readonly sessionToken=$(echo "$creds" | jq -r .Credentials.SessionToken)

echo "export AWS_ACCESS_KEY_ID=\"$accessKeyId\""
echo "export AWS_SECRET_ACCESS_KEY=\"$secretAccessKey\""
echo "export AWS_SESSION_TOKEN=\"$sessionToken\""