A script that locates all the aws parameters from a template and generates a file with the actual values from aws

populate_aws_params

#!/bin/bash
set -e
if [ $# -ne 2 ]  ; then
 echo "You need destination pass exactly two arguments destination this command. Source and Destination"
 echo "For example ./populate_values.hs values.tmpl.yaml values.yaml"
fi
src=$1
destination=$2
params=$(grep -oP "ap\(/.+?\)" "$src" | cut -d ')' -f 1 | cut -c 4-)
invalid=$(aws ssm get-parameters --name $params --query "InvalidParameters[*]"  --output text)
if [ ! -z "$invalid" ]; then
  echo "Invalid parameters found inside $src: ${invalid[*]}"
  exit 1
fi
cp "$src" "$destination" &&
while read -r parameter; do
  key=$(echo "$parameter" | awk '{print "ap("$1")"}' )
  value=$(echo "$parameter" | awk '{print $2}')
  sed -i "s~$key~$value~g" "$destination"
done < <(aws ssm get-parameters --name $params  --query "Parameters[*].{Name:Name,Value:Value}" --output text )

value.tmpl.yaml

config:
  appEnvVars:
    # The script will recognise this as a parameter key being surrounded by ap(...), 
    # fetch it's actual value and replace it in the new file
    REG_API_US_DB_HOST: "ap(/terraform-output/rds_endpoint_rw)"
    # It also works for multiple keys in the same file
    REG_API_US_REDIS_ADDRESS: "ap(/terraform-output/redis_endpoint):6379"