Implement Delete

8min
Terraform

Note: We recommend using the Terraform Plugin Framework for new provider development because it offers significant advantages compared to the SDKv2. Refer to the Plugin Framework tutorials to learn how to create providers using the framework.

In this tutorial, you will add delete capabilities to the order resource for a Terraform provider that interacts with the API of a fictional coffee-shop application called Hashicups. To do this, you will implement delete. This delete function invokes a DELETE request to the /orders/{orderId} endpoint.

Prerequisites

To follow this tutorial, you need:

a Golang 1.15+ installed and configured.
the Terraform 0.14+ CLI installed locally.
Docker and Docker Compose to run an instance of HashiCups locally.

Navigate to your terraform-provider-hashicups directory. Next, fetch new changes.

$ git fetch

Then, checkout the implement-update branch. This step is optional but recommended to ensure that your code matches the code from the previous tutorials.

$ git checkout implement-update

Clone the implement-update branch of the Terraform HashiCups Provider repository.

$ git clone --branch implement-update https://github.com/hashicorp/terraform-provider-hashicups

Change into the cloned repository.

$ cd terraform-provider-hashicups

Then, install all the provider's dependencies.

$ go mod tidy

Build provider binary

Next, build the binary and move it into your user Terraform plugins directory. This allows you to sideload and test the custom provider. Select the tab for your operating system for specific instructions.

$ make install
go build -o terraform-provider-hashicups
mv terraform-provider-hashicups ~/.terraform.d/plugins/hashicorp.com/edu/hashicups/0.2/darwin_amd64

Build the provider binary.

$ go build -o terraform-provider-hashicups

Retrieve your system's OS and ARCH. You can find a full list of supported GOOS and GOARCH here.

$ export OS_ARCH="$(go env GOHOSTOS)_$(go env GOHOSTARCH)"

Create the appropriate subdirectory within the user plugins directory for the HashiCups provider if it doesn't exist already.

$ mkdir -p ~/.terraform.d/plugins/hashicorp.com/edu/hashicups/0.2/$OS_ARCH

Next, move the binary to the appropriate subdirectory within your user plugins directory.

$ mv terraform-provider-hashicups ~/.terraform.d/plugins/hashicorp.com/edu/hashicups/0.2/$OS_ARCH

Build the provider binary.

$ go build -o terraform-provider-hashicups.exe

Create the appropriate subdirectory within the user plugins directory for the HashiCups provider if it doesn't exist already, replacing [OS_ARCH] with your system's OS_ARCH. You can find a full list of supported GO_ARCH here.

$ mkdir -p %APPDATA%\terraform.d\plugins\hashicorp.com\edu\hashicups\0.2\[OS_ARCH]

Then, move the binary to the appropriate subdirectory within your user plugins directory, replacing [OS_ARCH] with your system's OS_ARCH.

$ move terraform-provider-hashicups.exe %APPDATA%\terraform.d\plugins\hashicorp.com\edu\hashicups\0.2\[OS_ARCH]

Tip

The Perform CRUD operations with Providers tutorial explains why and how to sideload custom providers. Refer to it to learn more about where to install custom providers and how to reference them in your configuration.

Run HashiCups API

The HashiCups provider requires an instance of HashiCups. Navigate to the docker_compose directory.

$ cd docker_compose

Then, run docker-compose up to spin up a local instance of HashiCups on port 19090.

$ docker-compose up

Leave this terminal running.

In another terminal, verify that HashiCups is running by sending a request to its health check endpoint.

$ curl localhost:19090/health
ok

Create a HashiCups user

Create a user on HashiCups named education with the password test123. If you already did this in a previous tutorial, you can skip signing up and reuse your previous token.

$ curl -X POST localhost:19090/signup -d '{"username":"education", "password":"test123"}'
{"UserID":1,"Username":"education","token":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE1OTEwNzgwODUsInVzZXJfaWQiOjIsInVzZXJuYW1lIjoiZWR1Y2F0aW9uIn0.CguceCNILKdjOQ7Gx0u4UAMlOTaH3Dw-fsll2iXDrYU"}

$ curl -X POST localhost:19090/signin -d '{"username":"education", "password":"test123"}'
{"UserID":1,"Username":"education","token":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE1OTEwNzgwODUsInVzZXJfaWQiOjIsInVzZXJuYW1lIjoiZWR1Y2F0aW9uIn0.CguceCNILKdjOQ7Gx0u4UAMlOTaH3Dw-fsll2iXDrYU"}

Set the HASHICUPS_TOKEN environment variable to the token you retrieved in the previous step.

$ export HASHICUPS_TOKEN=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE1OTEwNzgwODUsInVzZXJfaWQiOjIsInVzZXJuYW1lIjoiZWR1Y2F0aW9uIn0.CguceCNILKdjOQ7Gx0u4UAMlOTaH3Dw-fsll2iXDrYU

Apply example configuration

Navigate to the terraform-provider-hashicups/examples directory. This contains a sample Terraform configuration for the Terraform HashiCups provider.

$ cd examples

Initialize your workspace.

$ terraform init

Apply the configuration. This creates an order and returns its values in your output.

$ terraform apply --auto-approve
Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

Navigate to your terraform-provider-hashicups directory.

$ cd ..

Your directory should have the following structure.

$ tree -L 2
.
├── Makefile
├── README.md
├── docker_compose
│   ├── conf.json
│   └── docker-compose.yml
├── examples
│   ├── coffee
│   ├── main.tf
│   ├── terraform.tfstate
│   └── terraform.tfstate.backup
├── go.mod
├── go.sum
├── hashicups
│   ├── data_source_coffee.go
│   ├── data_source_order.go
│   ├── provider.go
│   └── resource_order.go
├── main.go
└── vendor

If you're stuck at any point during this tutorial, refer to the implement-delete branch to see the changes implemented in this tutorial.

Implement delete

Replace the resourceOrderDelete function in hashicups/resource_order.go with the code snippet below. This function will delete the HashiCups order and Terraform resource.

hashicups/resource_order.go

func resourceOrderDelete(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
  c := m.(*hc.Client)

  // Warning or errors can be collected in a slice type
  var diags diag.Diagnostics

  orderID := d.Id()

  err := c.DeleteOrder(orderID)
  if err != nil {
    return diag.FromErr(err)
  }

  // d.SetId("") is automatically called assuming delete returns no errors, but
  // it is added here for explicitness.
  d.SetId("")

  return diags
}

Format your code.

$ go fmt ./...

Notice the m (meta) input parameter contains the HashiCups API Client set by the ConfigureContextFunc defined above. If an unauthenticated API Client is provided (no username/password), this function will fail and return an error message.

The function retrieves the order ID using d.ID() and deletes the order.

If the destroy callback returns without an error, the provider assumes the resource is destroyed and all state is removed.
If the destroy callback returns with an error, the provider assumes the resource still exists and all prior state is preserved.

The destroy callback should never update any state on the resource. In addition, the destroy callback should always handle the case where the resource might already be destroyed. If the resource is already destroyed, the destroy function should not return an error. If the target API doesn't have this functionality, the destroy function should verify the resource exists; if the resource does not exist, set the resource ID to "". This behavior allows Terraform users to manually delete resources without breaking Terraform.

Test the provider

Now that you've added delete capabilities to the order resource, verify that it works.

First, confirm that you are in the terraform-provider-hashicups root directory.

$ pwd
~/terraform-provider-hashicups

$ make install
go build -o terraform-provider-hashicups
mv terraform-provider-hashicups ~/.terraform.d/plugins/hashicorp.com/edu/hashicups/0.2/darwin_amd64

Build the provider binary.

$ go build -o terraform-provider-hashicups

Retrieve your system's OS and ARCH. You can find a full list of supported GOOS and GOARCH here.

$ export OS_ARCH="$(go env GOHOSTOS)_$(go env GOHOSTARCH)"

Create the appropriate subdirectory within the user plugins directory for the HashiCups provider if it doesn't exist already.

$ mkdir -p ~/.terraform.d/plugins/hashicorp.com/edu/hashicups/0.2/$OS_ARCH

Next, move the binary to the appropriate subdirectory within your user plugins directory.

$ mv terraform-provider-hashicups ~/.terraform.d/plugins/hashicorp.com/edu/hashicups/0.2/$OS_ARCH

Build the provider binary.

$ go build -o terraform-provider-hashicups.exe

$ mkdir -p %APPDATA%\terraform.d\plugins\hashicorp.com\edu\hashicups\0.2\[OS_ARCH]

Then, move the binary to the appropriate subdirectory within your user plugins directory, replacing [OS_ARCH] with your system's OS_ARCH.

$ move terraform-provider-hashicups.exe %APPDATA%\terraform.d\plugins\hashicorp.com\edu\hashicups\0.2\[OS_ARCH]

Tip

Navigate to the terraform-provider-hashicups/examples directory. This contains a sample Terraform configuration for the Terraform HashiCups provider.

$ cd examples

Initialize your workspace to refresh your HashiCups provider then destroy the configuration. This should delete your HashiCups order.

$ terraform init && terraform destroy --auto-approve
Destroy complete! Resources: 1 destroyed.

Verify that the provider updated your order by invoking the HashiCups API. Substitute the order number with your order ID and the auth token with your auth token.

$ curl -X GET -H "Authorization: ${HASHICUPS_TOKEN}" localhost:19090/orders/1

Next steps

In this tutorial, you added delete capabilities to the order resource.

If you were stuck during this tutorial, checkout the implement-delete branch to see the changes implemented in this tutorial.

The Terraform Provider Scaffold is a quick-start repository for creating a Terraform provider. Use this GitHub template when you're ready to create a custom provider.
To learn more about the Terraform Plugin SDK, refer to the Terraform Plugin SDK Documentation.
To learn how to publish a Terraform provider to the Terraform Registry, refer to the Publishing Providers to the Terraform Registry documentation.