> For the complete documentation index, see [llms.txt](https://developer.harness.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.harness.io/harness-solutions-factory/use-hsf/template-library/customizing-using-custom-htl.md).

# How to Customize an Existing Template Using Custom Harness Template Library

For the purpose of this tutorial we will be focusing on customizing the project creation workflow but this can be done for any workflow.

{% hint style="info" %}
**What is the idp\_registration\_mgr.yaml?**

It is a way to identify the scope of which a template should be deployed. Rather than defining the scope and restricting where the file can be deployed, templates are registered here instead.

Within this file workflows are not only scoped by organization but also scoped by modules that are purchased and if it is a default workflow that should be included for all HSF users.
{% endhint %}

Any workspaces that are created with the custom template library will now be configured with the **source:custom** tag, and have the appropriate connectors, branch and repos.

### Add a variable <a href="#add-a-variable" id="add-a-variable"></a>

Add a variable into the project creation workflow.

{% hint style="info" %}
For the purposes of this tutorial, examples are provided below. To learn more about the Harness Terraform provider, go to the [documentation](https://registry.terraform.io/providers/harness/harness/latest/docs)
{% endhint %}

1. Navigate to the [Terraform Harness Documentation](https://registry.terraform.io/providers/harness/harness/latest/docs)
2. Under Next Gen find `harness_platform_variables`
3. Go into your code editor and open up `custom-harness-template-library/harness-project`
4. Add in file **harness\_variables.tf** and paste in declaration from the Terraform docs
   * Change **org\_id** to `data.harness_platform_organization.selected.id`
     * You could use a variable but this was pulled from the others where the data object already exists.
   * Change **project\_id** to `data.harness_platform_project.selected.id`
     * You could use a variable but this was pulled from the others where the data object already exists.
   * Change **fixed\_value** to `var.application_id`

```hcl
resource "harness_platform_variables" "application_id"{ 
    identifier = "application_id" 
    name = "Application ID" 
    org_id = data.harness_platform_organization.selected.id 
    project_id = data.harness_platform_project.selected.id 
    type = "String" 
    spec { 
        value_type = "FIXED" 
        fixed_value = var.application_id
    }
}
```

5. Add in the **application\_id** variable into **variables.tf**

```hcl
variable "application_id"{ 
    type = string 
    description = "[Optional] Please provide your team's application ID" 
    default = "n/a" 
}
```

6. Add the variable to **catalog\_template.yaml**. This will tell the user what to do and pass the information.

```yaml
application_id: 
    title: "ServiceNOW Application Identifier" 
    type: string 
    description: "Please provide your team's application ID"
```

* If you wanted to add in validations you can add this in here and add in things like patterns, minLength, and maxLength.
* All new builds must have this field, so add it into required.
* Note: the default value covers all pre-existing builds
* Scroll down to **configure\_workspace** and under RESOURCE\_VARS add `application_id: ${{ parameters.application_id }}`
* This will pass in the application ID into workspace creation.
* Save, commit and push

7. Run the `Register Custom IDP Templates` pipeline since changes were made to the workflow.

Workflows are registered using APIs not git experience therefore the change would only take effect if it is reloaded back in.

### Add a new group <a href="#add-a-new-group" id="add-a-new-group"></a>

1. Create a new file under groups

* The name of the file is very important as it is going to determine the identifier
* As an example, create a Security Champions group by creating the Security\_Champions.yaml file that looks like this:

```yaml
tags: 
    purpose: Security Champions 
role bindings: 
    - role: _project_viewer 
        resource_group: _all_project_level_resources 
    - role: _sto_secops_role 
        resource_group: _all_project_level_resources
```

2. Save, commit and push