terraform provisioner local_exec , variable input example - unix1998/technical_notes GitHub Wiki

To use a variable for the input string and echo it in the local-exec provisioner, need modify the Terraform file to define a variable and then reference it in the command. Here's how you can do it:

Define the Variable: Define the variable in the Terraform configuration.
Prompt for Variable Input: Set the variable input to prompt manually.
Use the Variable in the local-exec Command: Reference the variable in the local-exec command.

Here is the modified Terraform file:

# Define the variable
variable "echo_message" {
  description = "The message to be echoed"
  type        = string
}

# Use the variable in the null_resource
resource "null_resource" "example" {
  provisioner "local-exec" {
    command = "echo ${var.echo_message}"
  }
}

Steps to Use the Modified Terraform File

Create the Terraform File: Create a file named main.tf and copy the above configuration into it.
```
touch main.tf
nano main.tf
```
Paste the above configuration into the main.tf file and save it.
Initialize the Directory: Initialize the Terraform working directory.
```
terraform init
```
Apply the Configuration: Apply the configuration. Terraform will prompt you to input the value for the echo_message variable.
```
terraform apply
```
When prompted, enter the message you want to be echoed.
```
var.echo_message
  The message to be echoed
  Enter a value: Hello from Terraform!
```

Full Example

For a complete example, assuming the message "Hello from Terraform!" is to be echoed:

Create the Directory: Create a directory for your Terraform configuration files.
```
mkdir terraform-echo
cd terraform-echo
```

Create the Terraform File: Create and edit the main.tf file.

touch main.tf
nano main.tf

Add the following content to the main.tf file:

variable "echo_message" {
  description = "The message to be echoed"
  type        = string
}

resource "null_resource" "example" {
  provisioner "local-exec" {
    command = "echo ${var.echo_message}"
  }
}

Initialize Terraform:
```
terraform init
```

Apply the Configuration:

terraform apply

When prompted, enter the desired message:

var.echo_message
  The message to be echoed
  Enter a value: Hello from Terraform!

This will output:

local-exec provisioner: Hello from Terraform!