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Terraform
Custom Framework Providers

Implement documentation generation

  • 8min
  • |
  • Terraform

In this tutorial, you will add documentation generation capabilities to a provider that interacts with the API of a fictional coffee-shop application called HashiCups. To do this, you will:

  1. Add terraform-plugin-docs to the provider.
    This enables the provider to automatically generate data source, resource, and function documentation.
  2. Add schema descriptions.
    This enhances the documentation to include a description for the provider itself, its data sources and resources, and each of their attributes.
  3. Add configuration examples.
    This enhances the documentation to include example Terraform configurations.
  4. Add resource import documentation.
    This enhances the resource documentation to include an example of how to import the resources that support it.
  5. Run documentation generation.
    This ensures that the documentation generation works as expected.

The terraform-plugin-docs Go module cmd/tfplugindocs command enables providers to implement documentation generation. The generation uses schema descriptions and conventionally placed files to produce provider documentation that is compatible with the Terraform Registry.

Prerequisites

To follow this tutorial, you need:

Navigate to your terraform-provider-hashicups directory.

Your code should match the 10-acceptance-tests directory from the example repository.

If you're stuck at any point during this tutorial, refer to the 11-documentation-generation directory in the example repository to see the code implemented in this tutorial.

Add schema descriptions

The tfplugindocs tool will automatically include schema-based descriptions, if present in a data source, provider, or resource's schema. The schema.Schema type's Description field describes the data source, provider, or resource itself. Each attribute's or block's Description field describes that particular attribute or block. These descriptions should be tailored to practitioner usage and include any caveats or value expectations, such as special syntax.

Open the internal/provider/provider.go file.

Add documentation to your provider by replacing the entire Schema method with the following, which adds Description fields to the provider's schema and each of it's attributes.

internal/provider/provider.go
// Schema defines the provider-level schema for configuration data.
func (p *hashicupsProvider) Schema(_ context.Context, _ provider.SchemaRequest, resp *provider.SchemaResponse) {
    resp.Schema = schema.Schema{
        Description: "Interact with HashiCups.",
        Attributes: map[string]schema.Attribute{
            "host": schema.StringAttribute{
                Description: "URI for HashiCups API. May also be provided via HASHICUPS_HOST environment variable.",
                Optional:    true,
            },
            "username": schema.StringAttribute{
                Description: "Username for HashiCups API. May also be provided via HASHICUPS_USERNAME environment variable.",
                Optional:    true,
            },
            "password": schema.StringAttribute{
                Description: "Password for HashiCups API. May also be provided via HASHICUPS_PASSWORD environment variable.",
                Optional:    true,
                Sensitive:   true,
            },
        },
    }
}

Open the internal/provider/coffees_data_source.go file.

Add documentation to your data source by replacing the entire Schema method with the following.

internal/provider/coffees_data_source.go
// Schema defines the schema for the data source.
func (d *coffeesDataSource) Schema(_ context.Context, _ datasource.SchemaRequest, resp *datasource.SchemaResponse) {
    resp.Schema = schema.Schema{
        Description: "Fetches the list of coffees.",
        Attributes: map[string]schema.Attribute{
            "id": schema.StringAttribute{
                Description: "Placeholder identifier attribute.",
                Computed:    true,
            },
            "coffees": schema.ListNestedAttribute{
                Description: "List of coffees.",
                Computed:    true,
                NestedObject: schema.NestedAttributeObject{
                    Attributes: map[string]schema.Attribute{
                        "id": schema.Int64Attribute{
                            Description: "Numeric identifier of the coffee.",
                            Computed:    true,
                        },
                        "name": schema.StringAttribute{
                            Description: "Product name of the coffee.",
                            Computed:    true,
                        },
                        "teaser": schema.StringAttribute{
                            Description: "Fun tagline for the coffee.",
                            Computed:    true,
                        },
                        "description": schema.StringAttribute{
                            Description: "Product description of the coffee.",
                            Computed:    true,
                        },
                        "price": schema.Float64Attribute{
                            Description: "Suggested cost of the coffee.",
                            Computed:    true,
                        },
                        "image": schema.StringAttribute{
                            Description: "URI for an image of the coffee.",
                            Computed:    true,
                        },
                        "ingredients": schema.ListNestedAttribute{
                            Description: "List of ingredients in the coffee.",
                            Computed:    true,
                            NestedObject: schema.NestedAttributeObject{
                                Attributes: map[string]schema.Attribute{
                                    "id": schema.Int64Attribute{
                                        Description: "Numeric identifier of the coffee ingredient.",
                                        Computed:    true,
                                    },
                                },
                            },
                        },
                    },
                },
            },
        },
    }
}

Open the internal/provider/order_resource.go file.

Add documentation to your resource by replacing the entire Schema method with the following.

internal/provider/order_resource.go
// Schema defines the schema for the resource.
func (r *orderResource) Schema(_ context.Context, _ resource.SchemaRequest, resp *resource.SchemaResponse) {
    resp.Schema = schema.Schema{
        Description: "Manages an order.",
        Attributes: map[string]schema.Attribute{
            "id": schema.StringAttribute{
                Description: "Numeric identifier of the order.",
                Computed:    true,
                PlanModifiers: []planmodifier.String{
                    stringplanmodifier.UseStateForUnknown(),
                },
            },
            "last_updated": schema.StringAttribute{
                Description: "Timestamp of the last Terraform update of the order.",
                Computed:    true,
            },
            "items": schema.ListNestedAttribute{
                Description: "List of items in the order.",
                Required:    true,
                NestedObject: schema.NestedAttributeObject{
                    Attributes: map[string]schema.Attribute{
                        "quantity": schema.Int64Attribute{
                            Description: "Count of this item in the order.",
                            Required:    true,
                        },
                        "coffee": schema.SingleNestedAttribute{
                            Description: "Coffee item in the order.",
                            Required:    true,
                            Attributes: map[string]schema.Attribute{
                                "id": schema.Int64Attribute{
                                    Description: "Numeric identifier of the coffee.",
                                    Required:    true,
                                },
                                "name": schema.StringAttribute{
                                    Description: "Product name of the coffee.",
                                    Computed:    true,
                                },
                                "teaser": schema.StringAttribute{
                                    Description: "Fun tagline for the coffee.",
                                    Computed:    true,
                                },
                                "description": schema.StringAttribute{
                                    Description: "Product description of the coffee.",
                                    Computed:    true,
                                },
                                "price": schema.Float64Attribute{
                                    Description: "Suggested cost of the coffee.",
                                    Computed:    true,
                                },
                                "image": schema.StringAttribute{
                                    Description: "URI for an image of the coffee.",
                                    Computed:    true,
                                },
                            },
                        },
                    },
                },
            },
        },
    }
}

Review function documentation

The tfplugindocs tool will generate documentation for functions based on the function definition. Open the compute_tax_function.go file and review the Definition method.

compute_tax_function.go
func (f *ComputeTaxFunction) Definition(ctx context.Context, req function.DefinitionRequest, resp *function.DefinitionResponse) {
    resp.Definition = function.Definition{
        Summary:     "Compute tax for coffee",
        Description: "Given a price and tax rate, return the total cost including tax.",

        Parameters: []function.Parameter{
            function.Float64Parameter{
                Name:        "price",
                Description: "Price of coffee item.",
            },
            function.Float64Parameter{
                Name:        "rate",
                Description: "Tax rate. 0.085 == 8.5%",
            },
        },
        Return: function.Float64Return{},
    }
}

Add configuration examples

The tfplugindocs tool will automatically include Terraform configuration examples from files with the following naming conventions:

  • Provider: examples/provider/provider.tf
  • Resources: examples/resources/TYPE/resource.tf
  • Data Sources: examples/data-sources/TYPE/data-source.tf
  • Functions: examples/functions/TYPE/function.tf

Replace TYPE with the name of the resource, data source, or function. For example: examples/resources/hashicups_order/resource.tf.

Open the examples/provider/provider.tf file and replace the existing code with the following.

examples/provider/provider.tf
# Configuration-based authentication
provider "hashicups" {
  username = "education"
  password = "test123"
  host     = "http://localhost:19090"
}

Remove the data source example from the scaffolding framework.

$ rm -r examples/data-sources/scaffolding_example

Create a examples/data-sources/hashicups_coffees directory.

$ mkdir -p examples/data-sources/hashicups_coffees

Create the examples/data-sources/hashicups_coffees/data-source.tf file with the following.

examples/data-sources/hashicups_coffees/data-source.tf
# List all coffees.
data "hashicups_coffees" "all" {}

Remove the resource example from the scaffolding framework.

$ rm -r examples/resources/scaffolding_example

Create the examples/resources/hashicups_order directory.

$ mkdir -p examples/resources/hashicups_order

Create the examples/resources/hashicups_order/resource.tf file with the following.

examples/resources/hashicups_order/resource.tf
# Manage example order.
resource "hashicups_order" "example" {
  items = [
    {
      coffee = {
        id = 3
      }
      quantity = 2
    },
  ]
}

Add resource import documentation

The tfplugindocs tool automatically will include Terraform import examples for resources with the file naming convention examples/resources/TYPE/import.sh.

Create a new examples/resources/hashicups_order/import.sh file with the following.

examples/resources/hashicups_order/import.sh
# Order can be imported by specifying the numeric identifier.
terraform import hashicups_order.example 123

Add function example

Create a examples/functions/compute_tax directory.

$ mkdir -p examples/functions/compute_tax

Create the examples/functions/compute_tax/function.tf file with the following.

examples/functions/compute_tax/function.tf
# Compute total price with tax
output "total_price" {
  value = provider::hashicups::compute_tax(5.00, 0.085)
}

Run documentation generation

Open tools/tools.go and replace the provider name in the documentation generation command.

tools.go
// Generate copyright headers
//go:generate go run github.com/hashicorp/copywrite headers -d .. --config ../.copywrite.hcl

// Format Terraform code for use in documentation.
// If you do not have Terraform installed, you can remove the formatting command, but it is suggested
// to ensure the documentation is formatted properly.
//go:generate terraform fmt -recursive ../examples/

// Generate documentation.
//go:generate go run github.com/hashicorp/terraform-plugin-docs/cmd/tfplugindocs generate --provider-dir .. -provider-name hashicups

Now that you have implemented the documentation generation functionality for your provider, run the cd tools; go generate ./... command to generate the documentation.

$ cd tools; go generate ./...
rendering website for provider "hashicups" (as "hashicups")
exporting schema from Terraform
compiling provider "hashicups"
using Terraform CLI binary from PATH if available, otherwise downloading latest Terraform CLI binary
running terraform init
getting provider schema
generating missing templates
generating missing resource content
generating new template for "hashicups_order"
generating missing data source content
generating new template for data-source "hashicups_coffees"
generating missing function content
generating new template for function "compute_tax"
generating missing provider content
generating new template for "hashicups"
rendering static website
cleaning rendered website dir
removing directory: "data-sources"
rendering templated website to static markdown
rendering "data-sources/coffees.md.tmpl"
rendering "functions/compute_tax.md.tmpl"
rendering "index.md.tmpl"
rendering "resources/order.md.tmpl"

View the generated files in the docs directory to verify that the documentation contains the expected descriptions, examples, and schema information.

Next steps

Congratulations! You have enhanced the provider with documentation generation capabilities.

If you were stuck during this tutorial, checkout the 11-documentation-generation directory in the example repository to see the code implemented in this tutorial.

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