# Terraformer — Reverse-Engineer Existing Cloud Infrastructure to Terraform

> Terraformer is a CLI tool by Google that reads live cloud resources from AWS, GCP, Azure, and 30+ other providers and generates corresponding Terraform HCL files and state, enabling infrastructure-as-code adoption on brownfield environments.

## Install

Save as a script file and run:

# Terraformer — Reverse-Engineer Existing Cloud Infrastructure to Terraform

## Quick Use
```bash
# Install
brew install terraformer
# Import all AWS EC2 resources in us-east-1
export AWS_DEFAULT_REGION=us-east-1
terraformer import aws --resources=ec2_instance --regions=us-east-1
# Output: generated/ directory with .tf and terraform.tfstate
```

## Introduction
Terraformer bridges the gap between manually provisioned cloud infrastructure and infrastructure-as-code. It reads existing resources from any supported provider and generates clean Terraform HCL files plus a matching state file, so teams can adopt Terraform without rebuilding from scratch.

## What Terraformer Does
- Imports live cloud resources into Terraform HCL and state files automatically
- Supports 30+ providers including AWS, GCP, Azure, Kubernetes, Datadog, and GitHub
- Filters imports by resource type, tags, or specific resource IDs
- Generates modular output with separate files per resource type
- Preserves resource relationships and inter-resource references in the generated code

## Architecture Overview
Terraformer uses the Terraform provider plugin system to discover and read resources. It invokes the provider's Read and List APIs, constructs an in-memory resource graph, and serializes the result to HCL files and a JSON state file. Each provider has a dedicated adapter that maps API responses to Terraform resource schemas.

## Self-Hosting & Configuration
- Install via Homebrew, Go install, or download prebuilt binaries from GitHub Releases
- Requires the matching Terraform provider plugin installed in your PATH or plugin directory
- Cloud credentials are read from standard environment variables (AWS_PROFILE, GOOGLE_CREDENTIALS, etc.)
- Use `--resources` and `--filter` flags to scope imports to specific resource types or IDs
- Output directory structure can be customized with `--path-pattern` and `--path-output`

## Key Features
- Broadest provider support among import tools with 30+ cloud and SaaS integrations
- Generates human-readable HCL rather than raw JSON state, making the output editable
- Tag-based filtering lets you import only resources matching specific labels
- Parallel resource discovery speeds up imports on large accounts
- Works with Terraform 0.12+ and OpenTofu for state compatibility

## Comparison with Similar Tools
- **Terraform import** — Built-in but only imports one resource at a time and generates no HCL; Terraformer bulk-imports with full code generation
- **Former2** — AWS-only CloudFormation generator; Terraformer covers 30+ providers and outputs HCL
- **Pulumi import** — Pulumi's import works only within the Pulumi ecosystem; Terraformer stays in vanilla Terraform
- **Spacelift** — SaaS platform with import features; Terraformer is free, open-source, and runs locally
- **driftctl** — Detects drift but does not generate code; Terraformer produces ready-to-use .tf files

## FAQ
**Q: Does Terraformer modify my existing cloud resources?**
A: No. Terraformer only reads resources via provider APIs. It never creates, updates, or deletes anything.

**Q: Can I import a specific subset of resources?**
A: Yes. Use `--filter` to target specific resource IDs or `--resources` to pick resource types.

**Q: Does it work with OpenTofu?**
A: Yes. The generated HCL and state files are compatible with both Terraform and OpenTofu.

**Q: How do I handle large AWS accounts with thousands of resources?**
A: Use region and resource type filters to break imports into manageable batches, and leverage the parallel discovery feature.

## Sources
- https://github.com/GoogleCloudPlatform/terraformer
- https://github.com/GoogleCloudPlatform/terraformer/blob/master/README.md

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Source: https://tokrepo.com/en/workflows/5d7b3271-39c9-11f1-9bc6-00163e2b0d79
Author: Script Depot