Script to generate temporary credentials when use switch roles in AWS.

generate_temp_credencial.sh

#!/bin/bash
#
# Generate temporary credencials

MAIN_ACCOUNT_CRED_FILE="$HOME/.aws/credentials"
MAIN_ACCOUNT_ACCESS=$(awk -F " = " '/aws_access_key_id/{sub("\r","") ; print $2}' "$MAIN_ACCOUNT_CRED_FILE")
MAIN_ACCOUNT_SECRET=$(awk -F " = " '/aws_secret_access_key/{sub("\r","") ; print $2}' "$MAIN_ACCOUNT_CRED_FILE")

ASSUMED_ACCOUNT_ID="<ACCOUNT_ID_THAT_WILL_BE_ASSUME>"
ROLE_ARN="arn:aws:iam::$ASSUMED_ACCOUNT_ID:role/<ROLE>"
MFA="<MFA_ARN>"
ROLE_NAME="<ACCOUNT_NAME_THAT_WILL_BE_ASSUME>"
TEMP_FILE="/tmp/temp_cred.json"

unset AWS_ACCESS_KEY_ID
unset AWS_SECRET_ACCESS_KEY
unset AWS_SESSION_TOKEN

AWS_ACCESS_KEY_ID=$MAIN_ACCOUNT_ACCESS AWS_SECRET_ACCESS_KEY=$MAIN_ACCOUNT_SECRET aws sts assume-role \
  --role-arn $ROLE_ARN \
  --serial-number $MFA \
  --token-code "$1" \
  --role-session-name $ROLE_NAME > $TEMP_FILE

TEMP_ACCESS=$(jq -r .Credentials.AccessKeyId < $TEMP_FILE)
TEMP_SECRET=$(jq -r .Credentials.SecretAccessKey < $TEMP_FILE)
TEMP_TOKEN=$(jq -r .Credentials.SessionToken < $TEMP_FILE)

echo "export AWS_ACCESS_KEY_ID=$TEMP_ACCESS
export AWS_SECRET_ACCESS_KEY=$TEMP_SECRET
export AWS_SESSION_TOKEN=$TEMP_TOKEN" > /tmp/assumed_role
source /tmp/assumed_role

exit 0