Workaround AWS CLI lack of support for IAM assume-role

aws_assume_role

#!/bin/bash
set -e

usage () {
  cat <<DOCUMENTATIONXX
Usage : $0 PROFILE_NAME COMMAND

This tool will take a named profile from your ~/.aws/credentials with only
a "role_arn = " line and no source profile, get temporary credentials for
the profile, and execute the rest of the parameters as a command with the
credentials set as environment variables.

Examples
  $0 production aws ec2 describe-instances --region=us-west-1


DOCUMENTATIONXX
}

if [ "$1" == "-h" -o "$1" == "--help" -o "$1" == "" ]; then
    usage
    exit 1
fi

source_profile_name=$1
role_arn=$(cat $HOME/.aws/credentials | grep -A 1 "\[$source_profile_name\]" | tail -n 1 | sed 's/role_arn = //')

session_name="${USER}-`hostname`-`date +%Y%m%d`"
sts=( $(
    aws sts assume-role \
    --role-arn "$role_arn" \
    --role-session-name "$session_name" \
    --query 'Credentials.[AccessKeyId,SecretAccessKey,SessionToken]' \
    --output text
) )

AWS_ACCESS_KEY_ID=${sts[0]} AWS_SECRET_ACCESS_KEY=${sts[1]} AWS_SESSION_TOKEN=${sts[2]} ${@:2}