Terraform aws_launch_template user_data error

I am trying to connect my ec2 web server to my database instance. I created s3 bucket where I put my php code given it is bigger than userdata 16k Character Limit and then I passed the bucket object to userdata file. Below is my code and error.

In my S3 bucket I have:

resource "aws_s3_bucket" "user_data" {
  bucket = var.bucket_name
  acl    = "private"
}

resource "aws_s3_object" "object" {
  bucket = aws_s3_bucket.user_data.id
  key    = "SamplePage.php"
  source = "web/SamplePage.php"
  etag = filemd5("web/SamplePage.php")
}

In my user_data.tftpl I have:

#!/bin/bash

sudo yum update -y
sudo amazon-linux-extras install php8.0 mariadb10.5
sudo yum install -y httpd
sudo systemctl start httpd
sudo systemctl enable httpd
sudo usermod -a -G apache ec2-user
sudo chown -R ec2-user:apache /var/www
sudo chmod 2775 /var/www
find /var/www -type d -exec sudo chmod 2775 {} \;
find /var/www -type f -exec sudo chmod 0664 {} \;
cd /var/www
mkdir inc
cd inc
sudo echo "<?php
define('DB_SERVER', '${rds_endpoint}');  
define('DB_USERNAME','${user}');
define('DB_PASSWORD', '${password}');
define('DB_DATABASE', '${dbname}');
?>" > dbinfo.inc
sudo aws s3 cp s3://${var.bucket_name}/SamplePage.php /var/www/html/SamplePage.php

launch template I have:

resource "aws_launch_template" "web" {
  name_prefix            = "web-"
  image_id               = data.aws_ami.amazon-linux.id
  instance_type          = var.instance_type
  vpc_security_group_ids = [aws_security_group.web_sg.id]
  key_name               = aws_key_pair.kp.key_name
  user_data              = templatefile("user_data.tftpl", { rds_endpoint =        "${aws_db_instance.rds.endpoint}", user = var.db_username, password = var.db_password, dbname = var.db_name})

In result, I am getting this error:

in resource "aws_launch_template" "web":
│   29:   user_data              = templatefile("user_data.tftpl", { rds_endpoint = "${aws_db_instance.rds.endpoint}", user = var.db_username, password = var.db_password, dbname = var.db_name})
│     ├────────────────
│     while calling templatefile(path, vars)
│
│ Invalid value for "vars" parameter: vars map does not contain key "var", referenced at       
│ user_data.tftpl:22,23-26.

How can I resolve this please.

The S3 bucket reference in the template file user_data.tftpl is using the regular variable reference:

sudo aws s3 cp s3://${var.bucket_name}/SamplePage.php /var/www/html/SamplePage.php

To fix that, you need to update the template file with the following:

#!/bin/bash

sudo yum update -y
sudo amazon-linux-extras install php8.0 mariadb10.5
sudo yum install -y httpd
sudo systemctl start httpd
sudo systemctl enable httpd
sudo usermod -a -G apache ec2-user
sudo chown -R ec2-user:apache /var/www
sudo chmod 2775 /var/www
find /var/www -type d -exec sudo chmod 2775 {} \;
find /var/www -type f -exec sudo chmod 0664 {} \;
cd /var/www
mkdir inc
cd inc
sudo echo "<?php
define('DB_SERVER', '${rds_endpoint}');  
define('DB_USERNAME','${user}');
define('DB_PASSWORD', '${password}');
define('DB_DATABASE', '${dbname}');
?>" > dbinfo.inc
sudo aws s3 cp s3://${bucket_name}/SamplePage.php /var/www/html/SamplePage.php

And then in the templatefile function call, adjust the variables that are passed in:

user_data              = templatefile("user_data.tftpl", {
  rds_endpoint = aws_db_instance.rds.endpoint
  user         = var.db_username
  password     = var.db_password
  dbname       = var.db_name
  bucket_name  = aws_s3_bucket.user_data.id
  })