Generate Infrastructure Plugin

In this section, you will find a guide on how to use legacy Terraform files to create Infrastructure Plugins.

How it works

To simplify the process of creating Infrastructure Plugins from existing Infrastructure as Code (IaC) code, the stk create plugin command includes a feature that generates an Infrastructure Plugin from your Terraform files.

It's important to provide values for the variables, as these will be used within the Terraform structures. The Plugin generator will analyze the existing Terraform structure, extract the local variables and their corresponding values, and create an Infrastructure Plugin based on these variables. These variables will then serve as the inputs for your Plugin.

Terraform Extracted Values

The extracted values will be:

Terraform local values (locals): values only used in the scope of the file in which they were declared.
Variables (variable): variables valid for the entire scope of the Terraform execution.

The Terraform file is analyzed, and each variable is extracted as follows:

The type of the local variable or value will be the input type. Terraform's supported types are string, number, and bool and will correspond to StackSpot's text, int, and bool types.
The variable description will be the description of the input.
The default values for the variable will be specified in the default input field.

Local Values

Local values (locals) will only be extracted if they are literal types, such as string, number, or bool. Variables that are assigned the reference of another variable will not be extracted. Additionally, local values that are null will also not be extracted.

Example:

main.tf
locals{
    var1 = "String text"
    var2 = local.var1
    var3 = null
}

The extracted local values will be converted into Jinja expressions in the Terraform file of your Plugin template, located in the templates-deploy folder, to correspond with the Plugin inputs. Any values that are not extracted will remain unchanged in your Terraform file.

Example:

main.tf
locals{
    var1 = "String text"
    var2 = 10
    var3 = null
    var4 = tolist(var.example_set)
}

After extracting the variables:

main.tf
locals{
    var1 = {{main_local_var1}}
    var2 = {{main_local_var2}}    
    var3 = null
    var4 = tolist(var.example_set)
}

Variables

Variables (variable) - all variables will be extracted if they are not a Terraform composite type, for example, object, list, map, etc. Since StackSpot does not support these Terraform types.

The supported types are:

string
number (integer or decimal)
bool

The values in variable will not be modified in your template, except for any other values nested within variable. Instead, these values will be saved in the terraform.tfvars file generated by Terraform, which contains all the values for each variable.

When a variable is extracted with a default value of 'null', it will be treated as an input of type text. In this case, it will not have the property 'default', and the property 'required' will be marked as false.

The terraform.tfvars file is a mechanism in Terraform that automatically generates a file with the values of all variables. This process ensures that users do not have to re-enter the same inputs every time, particularly for variables without a defined default value.

When StackSpot creates the Infrastructure Plugin, it will use or create this file if it does not already exist and configure it using Jinja expressions.

For example, consider the file terraform.tfvars with the following variables filled in:

variables.tf file:

variable "var1"{
    description = "Variable var1"
    type = string
    default = "var1 value"
}
variable "var2"{
    description = "Variable var2"
    type = string
    default = "var2 value"
}
variable "var3"{
    description = "Variable var3"
    type = string
    default = "var3 value"
}
variable "var4"{
    description = "Variable var4"
    type = number
    default = 2.5
}
variable "var5"{
    description = "Variable var5"
    type = string
    default = "null"
}
variable "var6"{
    description = "Variable var6"
    type = bool
    default = true
}

File terraform.tfvars existing and populated:

terraform.tfvars
var1 = "string text"
var2 = "string text"
var3 = "string text"
var4 = 11.5
var5 = "null"
var6 = true

terraform.tfvars file transformed after extracting variables or generated during Plugin creation:

terraform.tfvars
var1 = {{variables_var_var1}}
var2 = {{variables_var_var2}}
var3 = {{variables_var_var3}}
var4 = {{variables_var_var4}}
var5 = {{variables_var_var5 or "null"}}
var6 = {{variables_var_var6}}

tip

With the terraform.In the tfvars file, you can see all the variable variables that were extracted (values replaced by a Jinja expression) and those that were not. This file does not include the values in the locals block.

When applying the Infrastructure Plugin in the terraform.tfvars file, the values with the Jinja expressions will be replaced when the template is rendered.

Creating the Infrastructure Plugin

To create the Plugin, in addition to the Plugin name, use the following parameters when executing the stk create plugin command:

--type: Plugin type. The type must be "infra".
--source-type: Source file type. The accepted type is "terraform".
--source-path: Path to a folder with Terraform files.

Syntax:

stk create plugin name-plugin-infra --type infra --source-type terraform --source-path FOLDER/FILES/TERRAFORM

Example:

Terraform files in folder 'Documents/infra-iac'

stk create plugin plugin-infra-legacy --type infra --source-type terraform --source-path localUser/Documents/infra-iac

Your Infrastructure Plugin will be generated in the current folder where you run the command. Check all the files in the templates-deploy folder and the Plugin inputs in the plugin.yaml file. You must manually handle the values not extracted into inputs for your Plugin. For all the 'stk create plugin' options, see the StackSpot commands page.

How ​​it works

Terraform Extracted Values

Local Values

Variables

Creating the Infrastructure Plugin

How it works