Support Write-Only Attributes + Ephemeral Guidance for Secret Fields (Terraform ≥1.12 / OpenTofu ≥1.11)

Summary

We should consider adding write-only secret-handling in the Airbyte Terraform provider to support:

1. Write-only attributes for connector credentials and API secrets
2. Clear documentation for ephemeral input values (Terraform ≥1.12 / OpenTofu ≥1.11)
3. Avoid reliance on secret values in diff/state logic

This prevents secrets from being persisted to Terraform state files while remaining fully compatible with modern Terraform and OpenTofu.

Background

Historically we’ve relied on Sensitive: true in schema.
This hides values from CLI output but does not prevent secrets from being written to state.

Terraform ≥1.12 and OpenTofu ≥1.11 now support write-only attributes and ephemeral values.

Given that Airbyte secrets are sent to the API and not retrievable afterward, we are a strong candidate for adopting write-only attributes.

Goals

• Prevent connector secrets from being stored in Terraform state
• Align with modern Terraform security best practices
• Improve provider security posture
• Provide clear user guidance for ephemeral variable usage

Proposed Changes

1. Convert secret fields to write-only attributes (Sensitive + WriteOnly, omit in Read()).
2. Ensure diff logic does not depend on secret values.
3. Document ephemeral variable usage for Terraform ≥1.12 / OpenTofu ≥1.11.

Acceptance Criteria

• Secret attributes converted to write-only where appropriate
• Read() logic does not return secrets
• Documentation updated
• Terraform 1.12+ compatibility confirmed
• Tests validate secrets are not stored in state

Related Resources

• Terraform Ephemeral Values: https://developer.hashicorp.com/terraform/language/values/ephemeral
• Terraform Plugin Framework Write-Only Attributes: https://developer.hashicorp.com/terraform/plugin/framework/handling-data/write-only
• OpenTofu Ephemerality: https://opentofu.org/docs/v1.11/language/ephemerality/
• Terraform Sensitive Values: https://developer.hashicorp.com/terraform/language/values/sensitive