Custom Terraform Providers: How to Simplify Their Creation with HashiCorp Generators

Creating a custom Terraform provider can be long and complex. With HashiCorp’s generators, you can automate up to 50% of the work starting from an OpenAPI specification. Fewer errors, greater scalability, and significant time savings for your teams.

In a context where agility and cloud infrastructure scalability have become strategic levers, Infrastructure as Code (IaC) has emerged as a vital standard. To meet this need, we use Terraform to automate cloud resource management. And when it comes to integrating APIs into our workflows, custom providers are essential.

But how can you create these providers quickly without overburdening your tech teams? To address this challenge, HashiCorp offers two powerful tools that automate the process: the OpenAPI Code Spec Generator and the Framework Generator. Together, they enable the creation of robust Terraform providers based on existing API specifications, ensuring security, consistency, performance, and scalability.

A Generation Pipeline Designed for Large-Scale Projects

The combination of HashiCorp’s two generators forms an automated pipeline that turns an OpenAPI specification file into a fully functional Terraform provider. Here’s how it works:

1. OpenAPI Code Spec Generator
   → Uses an OpenAPI file (YAML or JSON) + a configuration file generator_config.yml
   → Outputs a structured provider_code_spec.json file
2. Framework Generator
   → Uses provider_code_spec.json to automatically generate the provider code (schemas, models, Go files, etc.)

Result: A provider that is 50% ready, with minimal manual configuration.

Deep Dive into the File `generator_config.yml` : Control, Customization, and Clarity

This configuration file allows you to define which resources to expose (e.g., application) and which fields to include or ignore (e.g., type, secret, etc.):

provider:
  name: logto

resources:
  application:
    read:
      path: /api/applications/{id}
      method: GET
    create:
      path: /api/applicationns
      method: POST
    update:
      path: /api/applications/{id}
      mathod: PUT
    delete:
      path: /api/applications/{id}
      method: DELETE
    schema:
      ignores:
        - type
        - oidcClientMetadata
        - createdAt
        - customClientMetadata
        - customData
        - secret
        - isAdmin
        - isThirdParty
        - protectedAppMetadata

datasources: []

This allows you to:

• Avoid overloading the provider with unnecessary data
• Keep each resource readable and maintainable
• Precisely tailor the developer experience when using Terraform

The 4 Key Benefits for Your Technical Teams

1. Significant Time Savings

No more manually writing schemas or parsing API docs for days. The generator handles it. Your developers focus on high-value tasks.

2. Code Consistency & Standardization

All resources follow a uniform structure, making collaboration, code review, and long-term scaling easier.

3. Fewer Human Errors

Automation prevents missing fields, type errors, and inconsistencies between the API and the infrastructure code.

4. Easy Maintenance

New API version? Just update the OpenAPI file and config, then regenerate. A massive time saver for evolving projects.

The 4 Strategic Benefits for Leadership Teams

1. Accelerated Time-to-Market

Automated provider generation drastically reduces development time. Teams deliver faster, projects progress smoothly, and business gains arrive sooner.

2. Sustainable Reduction of Technical Debt

With structured, consistent, and auto-generated code, projects avoid a pile-up of hard-to-maintain custom solutions. You lay down solid technical foundations.

3. Increased Team Autonomy

No need to rely on Terraform experts for each integration. Teams gain independence, critical dependencies drop, and senior staff workload lightens.

4. Controlled Cloud Scalability

Each new business API can be integrated quickly without sacrificing quality. This ability to replicate a reliable process at scale becomes a true growth driver.

When to Use This Approach

• The API to integrate is well-documented with OpenAPI
• The project involves several custom cloud resources
• You want to minimize delivery time without compromising quality
• You need to regularly update your Terraform integrations

In Conclusion: A Powerful Lever to Industrialize Your Terraform Providers

For CTOs, cloud architects, and project teams, this generation pipeline is a strategic solution for rapidly integrating business services into your cloud infrastructure. It saves time, reduces errors, and promotes standardization — all key success factors in today’s digital transformation landscape.

Want to learn more?

Get in touch with us!