Enhancing Terraform: User Input Before Apply

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Enhancing Terraform: User Input Before Apply

Hey everyone! Let's dive into a cool feature idea for Terraform: requiring user input before a terraform apply. This is all about adding an extra layer of safety and control to your infrastructure deployments. We'll break down why this is useful, the problems it solves, and how it could work.

Feature Description: User Input Confirmation

This feature is pretty straightforward. Before Terraform actually applies any changes, it would prompt the user for confirmation. Think of it as a mandatory "are you sure?" step. The goal is to prevent accidental deployments or unintended changes, especially in automated pipelines or when multiple people are collaborating on the same infrastructure. The user would be given a clear summary of the planned changes, and then asked to confirm before the apply command proceeds. This confirmation could be as simple as typing "yes" or selecting an option, or it could be a more sophisticated interactive process.

Detailed Breakdown

  • Change Summary: Terraform would generate its normal plan, but instead of immediately applying it, it would present the user with a human-readable summary of the proposed changes. This should be as clear and concise as possible, highlighting what resources are being added, modified, or deleted.
  • Prompt for Input: The system would then prompt the user for confirmation. The exact method of prompting (e.g., command-line input, a GUI, or integration with CI/CD tools) could be flexible, depending on the environment.
  • Confirmation Options: The confirmation options could vary. At a minimum, there would be an option to confirm the apply (e.g., typing "yes" or pressing a specific key). There could also be options to view more details about the plan, cancel the apply, or save the plan for later review.
  • Flexibility: The feature should be flexible enough to allow for disabling the prompt in certain scenarios (e.g., in fully automated deployments where user interaction isn't possible or desirable).

This feature enhances the safety of your deployments. Ensuring that changes are reviewed and approved before implementation is a critical step in a robust deployment process. Let’s talk about why it's a great idea, the issues it tackles, and how it might work in practice.

Problem Statement: Avoiding Unintentional Changes

So, why do we need this? Well, the main problem this feature tackles is preventing accidental or unwanted changes to your infrastructure. We've all been there: you run a terraform apply, and something unexpected happens. Maybe you made a typo in a configuration file, or maybe you didn't fully understand the implications of the changes. This feature acts as a safety net, catching these kinds of errors before they cause problems. It prevents unintended deployments, especially in complex environments where changes can have far-reaching consequences.

The Risks of Unchecked Applies

  • Configuration Errors: Simple mistakes in your Terraform code can lead to significant problems. Requiring user input gives you a chance to catch these errors before they're applied.
  • Misunderstandings: Infrastructure as code can be complex. The terraform plan output can sometimes be difficult to understand fully. The confirmation step gives users a chance to review the changes and clarify any uncertainties.
  • Automated Pipelines: In automated CI/CD pipelines, changes are often applied automatically. This feature allows you to introduce a manual review step, even in automated workflows.
  • Collaboration: When multiple people are working on the same infrastructure, this feature helps prevent conflicts and ensures that everyone is on the same page before changes are applied.

This is all about adding a layer of protection against the most common risks associated with infrastructure deployments. It is a safeguard against human error and miscommunication.

Proposed Solution: Implementing Interactive Confirmation

Here’s how we could see this implemented. When a user runs terraform apply, Terraform would first generate a plan as it currently does. However, instead of immediately applying the changes, it would present the plan to the user in a clear, concise format. This could be a summary of what's being added, modified, or deleted, along with any relevant details.

Interactive Prompting

After presenting the plan, Terraform would prompt the user for confirmation. The exact implementation of this could vary. Here are a few options:

  • Command-Line Input: A simple "yes/no" prompt, where the user types "yes" to confirm or "no" to cancel.
  • Interactive Menu: A more sophisticated menu that allows users to review the plan in more detail, see specific resource changes, or choose different options.
  • GUI Integration: Integration with a GUI, such as the Terraform Cloud UI, to provide a more visual and interactive confirmation experience.
  • CI/CD Integration: Options for integrating with CI/CD systems, such as Jenkins or GitLab CI, to allow for approvals and notifications.

Configuration Options

The feature would need to be configurable. You might want to disable the prompt in certain situations (e.g., in a fully automated CI/CD pipeline). This could be achieved through a command-line flag (e.g., --confirm=false) or through a configuration setting in your Terraform code.

Example Implementation

terraform apply

Terraform will perform the actions above.  Only 'yes' will be accepted to apply.

Enter a value: yes

Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

This approach provides flexibility and control, allowing users to tailor the behavior to their specific needs. It’s all about creating a safer, more reliable deployment process.

Alternative Solutions: Exploring Other Approaches

While requiring user input is a direct solution, let's look at other ways to achieve similar goals. Other solutions could complement or even replace this feature depending on the specific use case and infrastructure setup.

Terraform Cloud

Terraform Cloud already provides some of these features, like the ability to review plans and require approvals before applying changes. However, this is a paid service and requires using Terraform Cloud.

Automated Testing

Implementing robust automated testing can catch many of the errors that a user confirmation would. This involves writing tests that validate your Terraform code and ensure that your infrastructure behaves as expected.

Code Reviews

Another approach is to implement a code review process. This means that before any Terraform code is merged and applied, it is reviewed by another team member. This provides a second pair of eyes to catch any potential errors or issues.

Combining Solutions

The best approach might be to combine these solutions. For example, you could use automated testing to catch common errors, code reviews to ensure quality, and user input before applying changes to provide an extra layer of safety. The ideal solution depends on the size and complexity of your infrastructure and your team's workflows. Each approach has its pros and cons, and the best choice depends on the specific context.

Use Case: Real-World Scenarios

Let’s look at some real-world examples to show why this feature is useful. Here's how this feature would shine in practical situations:

Scenario 1: Preventing Production Outages

Imagine you're making a change to a production environment. A small mistake in your Terraform code could lead to a major outage. By requiring user input, you get a chance to review the plan and catch the error before it affects your users. This confirmation step acts as a critical safeguard against unintentional production outages.

Scenario 2: Collaborative Environments

In a team environment, multiple people might be working on the same infrastructure. Requiring user input ensures that everyone is on the same page before changes are applied. It provides a shared understanding of what changes are being made and reduces the risk of conflicts or misunderstandings.

Scenario 3: Automated CI/CD Pipelines

Even in automated pipelines, there are times when you might want to introduce a manual review step. Maybe you're deploying a critical change, or maybe you want to ensure that a specific person approves the changes before they're applied. This feature would allow you to integrate a manual approval step into your automated workflows.

Scenario 4: Complex Infrastructure

When dealing with complex infrastructure, it can be easy to miss something in the terraform plan output. The user input step gives you an extra opportunity to review the changes and make sure you understand the implications before they're applied. This is particularly important when dealing with critical systems.

These scenarios illustrate how this feature can be valuable in various situations, from preventing outages to improving collaboration and managing complex deployments. These are just a few examples, and the specific use cases will vary depending on your specific infrastructure and workflows.

Additional Context: Enhancements and Considerations

Let’s talk about some additional things to think about to make this feature even better. Here are some extra ideas and considerations:

Plan Review Tools

Integrate the feature with existing plan review tools or add the ability to export the plan to a file for external review. This could include options to:

  • Integrate with existing tools: allow users to pipe the plan output to tools like terraform-docs or other linters.
  • Export plans: allow users to save the terraform plan to a file. This is especially helpful if someone needs to review it offline or share it for a second opinion.

Customizable Prompts

Allow users to customize the prompt message or even add their own custom validation steps. This could include options for:

  • Custom messages: the ability to provide a more specific prompt tailored to the changes being made.
  • Custom validations: the ability to run custom scripts or checks before the apply command is executed.

Integration with Automation

Make sure the feature plays nicely with automation tools, like CI/CD systems. This could include options for:

  • Environment variables: using environment variables to control the confirmation behavior in automated environments.
  • CI/CD plugins: developing plugins or integrations for popular CI/CD systems, such as Jenkins or GitLab CI.

Accessibility

Ensure that the feature is accessible to users with disabilities. This is all about:

  • Keyboard navigation: making sure that all the interactive elements can be controlled using a keyboard.
  • Screen reader compatibility: ensuring that the feature works well with screen readers.

These additions would make the feature even more powerful and versatile. They would make the Terraform apply process safer, more flexible, and better suited for a wide range of use cases.