How to develop your own provider in Terraform?

To develop your own Terraform provider, you need to:

1. Choose a language: Go - the primary language for Terraform providers.

2. Install SDK: Go and Terraform Plugin SDK.

3. Create a project structure:

   # Create base files
   mkdir terraform-provider-myprovider
   cd terraform-provider-myprovider
   go mod init github.com/myorg/terraform-provider-myprovider
   go get github.com/hashicorp/terraform-plugin-sdk/v2
   

4. Implement the provider: create a provider.go file and define the Provider structure, including:

   • Schema: defining provider configuration parameters.
   • ResourcesMap: mapping resource names to their implementations.
   • DataSourcesMap: mapping data source names to their implementations.

   package main
   
   import (
   	"context"
   
   	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
   	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
   )
   
   func Provider() *schema.Provider {
   	return &schema.Provider{
   		Schema: map[string]*schema.Schema{
   			"endpoint": { // Example provider configuration parameter
   				Type:        schema.TypeString,
   				Optional:    true,
   				DefaultFunc: schema.EnvDefaultFunc("MYPROVIDER_ENDPOINT", nil),
   			},
   		},
   		ResourcesMap: map[string]*schema.Resource{
   			"myprovider_resource": resourceMyProviderResource(), // Resource implementation
   		},
   		DataSourcesMap: map[string]*schema.Resource{
   			// Data sources implementation
   		},
   		ConfigureContextFunc: providerConfigure, // Client setup function
   	}
   }
   
   func providerConfigure(ctx context.Context, d *schema.ResourceData) (interface{}, diag.Diagnostics) {
   	// Provider client setup logic
   	return nil, nil
   }
   
   func main() {
   	// Entry point
   }
   

5. Implement resources and data sources: create separate files for each resource and data source (e.g., resource_myprovider_resource.go). Each resource should implement functions:

   • Schema: resource parameter definitions.
   • Create: create resource.
   • Read: read resource state.
   • Update: update resource.
   • Delete: delete resource.
   • Exists: check resource existence (optional).

   package main
   
   import (
       "context"
   
       "github.com/hashicorp/terraform-plugin-sdk/v2/diag"
       "github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
   )
   
   func resourceMyProviderResource() *schema.Resource {
       return &schema.Resource{
           CreateContext: resourceMyProviderResourceCreate,
           ReadContext:   resourceMyProviderResourceRead,
           UpdateContext: resourceMyProviderResourceUpdate,
           DeleteContext: resourceMyProviderResourceDelete,
           Schema: map[string]*schema.Schema{
               "name": { // Example resource parameter
                   Type:     schema.TypeString,
                   Required: true,
               },
           },
       }
   }
   
   func resourceMyProviderResourceCreate(ctx context.Context, d *schema.ResourceData, m interface{}) diag.Diagnostics {
       // Resource creation logic
       return nil
   }
   // ... Implement Read, Update, Delete
   

6. Compile: build the provider executable.

7. Install: place the compiled binary in the Terraform plugins directory (~/.terraform.d/plugins/ or another location specified in Terraform configuration).

8. Test: write Acceptance Tests to verify the provider's correctness.

Additional steps may include:

• Document the provider.
• Publish the provider to Terraform Registry.
• Use a framework instead of SDK for more modern development.