pre-commit-opentofu/README.md

# Collection of git hooks for Terraform to be used with [pre-commit framework](http://pre-commit.com/)

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* [How to install](#how-to-install)
  * [1. Install dependencies](#1-install-dependencies)
    * [MacOS](#macos)
    * [Ubuntu 18.04](#ubuntu-1804)
      * [Ubuntu 20.04](#ubuntu-2004)
  * [2. Install the pre-commit hook globally](#2-install-the-pre-commit-hook-globally)
  * [3. Add configs and hooks](#3-add-configs-and-hooks)
  * [4. Run](#4-run)
* [Available Hooks](#available-hooks)
* [Hooks notes](#hooks-notes)
  * [terraform_docs](#terraform_docs)
  * [terraform_tflint](#terraform_tflint)
  * [terraform_tfsec](#terraform_tfsec)
  * [terraform_validate](#terraform_validate)
* [Notes for contributors](#notes-for-contributors)
  * [Run and debug hooks locally](#run-and-debug-hooks-locally)
* [Authors](#authors)
* [License](#license)

## How to install

### 1. Install dependencies

* [`pre-commit`](https://pre-commit.com/#install)
* [`terraform-docs`](https://github.com/terraform-docs/terraform-docs) required for `terraform_docs` hooks. `GNU awk` is required if using `terraform-docs` older than 0.8.0 with Terraform 0.12.
* [`TFLint`](https://github.com/terraform-linters/tflint) required for `terraform_tflint` hook.
* [`TFSec`](https://github.com/liamg/tfsec) required for `terraform_tfsec` hook.
* [`coreutils`](https://formulae.brew.sh/formula/coreutils) required for `terraform_validate` hook on macOS (due to use of `realpath`).
* [`checkov`](https://github.com/bridgecrewio/checkov) required for `checkov` hook.
* [`terrascan`](https://github.com/accurics/terrascan) required for `terrascan` hook.

or build and use the Docker image locally as mentioned below in the `Run` section.

#### MacOS

```bash
brew install pre-commit gawk terraform-docs tflint tfsec coreutils checkov terrascan
```

#### Ubuntu 18.04

```bash
sudo apt update
sudo apt install -y gawk unzip software-properties-common
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt install -y python3.7 python3-pip
python3 -m pip install --upgrade pip
pip3 install pre-commit
curl -L "$(curl -s https://api.github.com/repos/terraform-docs/terraform-docs/releases/latest | grep -o -E "https://.+?-linux-amd64.tar.gz")" > terraform-docs.tgz && tar xzf terraform-docs.tgz && chmod +x terraform-docs && sudo mv terraform-docs /usr/bin/
curl -L "$(curl -s https://api.github.com/repos/terraform-linters/tflint/releases/latest | grep -o -E "https://.+?_linux_amd64.zip")" > tflint.zip && unzip tflint.zip && rm tflint.zip && sudo mv tflint /usr/bin/
curl -L "$(curl -s https://api.github.com/repos/aquasecurity/tfsec/releases/latest | grep -o -E "https://.+?tfsec-linux-amd64" | head -n 1)" > tfsec && chmod +x tfsec && sudo mv tfsec /usr/bin/
curl -L "$(curl -s https://api.github.com/repos/accurics/terrascan/releases/latest | grep -o -E "https://.+?_Linux_x86_64.tar.gz")" > terrascan.tar.gz && tar -xf terrascan.tar.gz terrascan && rm terrascan.tar.gz && sudo mv terrascan /usr/bin/
python3.7 -m pip install -U checkov
```

##### Ubuntu 20.04

```bash
sudo apt update
sudo apt install -y gawk unzip software-properties-common
sudo apt install -y python3 python3-pip
python3 -m pip install --upgrade pip
pip3 install pre-commit
curl -L "$(curl -s https://api.github.com/repos/terraform-docs/terraform-docs/releases/latest | grep -o -E "https://.+?-linux-amd64.tar.gz")" > terraform-docs.tgz && tar -xzf terraform-docs.tgz terraform-docs && chmod +x terraform-docs && sudo mv terraform-docs /usr/bin/
curl -L "$(curl -s https://api.github.com/repos/terraform-linters/tflint/releases/latest | grep -o -E "https://.+?_linux_amd64.zip")" > tflint.zip && unzip tflint.zip && rm tflint.zip && sudo mv tflint /usr/bin/
curl -L "$(curl -s https://api.github.com/repos/aquasecurity/tfsec/releases/latest | grep -o -E "https://.+?tfsec-linux-amd64" | head -n 1)" > tfsec && chmod +x tfsec && sudo mv tfsec /usr/bin/
curl -L "$(curl -s https://api.github.com/repos/accurics/terrascan/releases/latest | grep -o -E "https://.+?_Linux_x86_64.tar.gz")" > terrascan.tar.gz && tar -xf terrascan.tar.gz terrascan && rm terrascan.tar.gz && sudo mv terrascan /usr/bin/
pip3 install -U checkov
```


### 2. Install the pre-commit hook globally

Note: not needed if you use the Docker image

```bash
DIR=~/.git-template
git config --global init.templateDir ${DIR}
pre-commit init-templatedir -t pre-commit ${DIR}
```

### 3. Add configs and hooks

Step into the repository you want to have the pre-commit hooks installed and run:

```bash
git init
cat <<EOF > .pre-commit-config.yaml
repos:
- repo: git://github.com/antonbabenko/pre-commit-terraform
  rev: <VERSION> # Get the latest from: https://github.com/antonbabenko/pre-commit-terraform/releases
  hooks:
    - id: terraform_fmt
    - id: terraform_docs
EOF
```

### 4. Run

After pre-commit hook has been installed you can run it manually on all files in the repository

```bash
pre-commit run -a
```

or you can also build and use the provided Docker container, which wraps all dependencies by

```bash
# first building it
docker build -t pre-commit .
# and then running it in the folder
# with the terraform code you want to check by executing
docker run -v $(pwd):/lint -w /lint pre-commit run -a
```

## Available Hooks

There are several [pre-commit](https://pre-commit.com/) hooks to keep Terraform configurations (both `*.tf` and `*.tfvars`) and Terragrunt configurations (`*.hcl`) in a good shape:

| Hook name                                        | Description                                                                                                                                      |
| ------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------ |
| `terraform_fmt`                                  | Rewrites all Terraform configuration files to a canonical format. [Hook notes](#terraform_docs)                                                  |
| `terraform_validate`                             | Validates all Terraform configuration files. [Hook notes](#terraform_validate)                                                                   |
| `terraform_docs`                                 | Inserts input and output documentation into `README.md`. Recommended.                                                                            |
| `terraform_docs_without_aggregate_type_defaults` | Inserts input and output documentation into `README.md` without aggregate type defaults.                                                         |
| `terraform_docs_replace`                         | Runs `terraform-docs` and pipes the output directly to README.md                                                                                 |
| `terraform_tflint`                               | Validates all Terraform configuration files with [TFLint](https://github.com/terraform-linters/tflint). [Hook notes](#terraform_tflint).         |
| `terragrunt_fmt`                                 | Rewrites all [Terragrunt](https://github.com/gruntwork-io/terragrunt) configuration files (`*.hcl`) to a canonical format.                       |
| `terragrunt_validate`                            | Validates all [Terragrunt](https://github.com/gruntwork-io/terragrunt) configuration files (`*.hcl`)                                             |
| `terraform_tfsec`                                | [TFSec](https://github.com/liamg/tfsec) static analysis of terraform templates to spot potential security issues. [Hook notes](#terraform_tfsec) |
| `checkov`                                        | [checkov](https://github.com/bridgecrewio/checkov) static analysis of terraform templates to spot potential security issues.                     |
| `terrascan`                                      | [terrascan](https://github.com/accurics/terrascan) Detect compliance and security violations.                                                    |

Check the [source file](https://github.com/antonbabenko/pre-commit-terraform/blob/master/.pre-commit-hooks.yaml) to know arguments used for each hook.

## Hooks notes

### terraform_docs

1. `terraform_docs` and `terraform_docs_without_aggregate_type_defaults` will insert/update documentation generated by [terraform-docs](https://github.com/terraform-docs/terraform-docs) framed by markers:

    ```txt
    <!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->

    <!-- END OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
    ```

    if they are present in `README.md`.

2. `terraform_docs_replace` replaces the entire README.md rather than doing string replacement between markers. Put your additional documentation at the top of your `main.tf` for it to be pulled in. The optional `--dest` argument lets you change the name of the file that gets created/modified.

    Example:

    ```yaml
    hooks:
      - id: terraform_docs_replace
        args: ['--sort-by-required', '--dest=TEST.md']
    ```

3. It is possible to pass additional arguments to shell scripts when using `terraform_docs` and `terraform_docs_without_aggregate_type_defaults`. Send pull-request with the new hook if there is something missing.

### terraform_tflint

1. `terraform_tflint` supports custom arguments so you can enable module inspection, deep check mode etc.

    Example:

    ```yaml
    hooks:
      - id: terraform_tflint
        args: ['--args=--deep']
    ```

    In order to pass multiple args, try the following:

    ```yaml
     - id: terraform_tflint
       args:
          - '--args=--deep'
          - '--args=--enable-rule=terraform_documented_variables'
    ```

3. When you have multiple directories and want to run `tflint` in all of them and share single config file it is impractical to hard-code the path to `.tflint.hcl` file. The solution is to use `__GIT_WORKING_DIR__` placeholder which will be replaced by `terraform_tflint` hooks with Git working directory (repo root) at run time. For example:

    ```yaml
    hooks:
      - id: terraform_tflint
        args:
          - '--args=--config=__GIT_WORKING_DIR__/.tflint.hcl'
    ```


### terraform_tfsec

1. `terraform_tfsec` will consume modified files that pre-commit
    passes to it, so you can perform whitelisting of directories
    or files to run against via [files](https://pre-commit.com/#config-files)
    pre-commit flag

    Example:

    ```yaml
    hooks:
      - id: terraform_tfsec
        files: ^prd-infra/
    ```

    The above will tell pre-commit to pass down files from the `prd-infra/` folder
    only such that the underlying `tfsec` tool can run against changed files in this
    directory, ignoring any other folders at the root level

2. To ignore specific warnings, follow the convention from the
[documentation](https://github.com/liamg/tfsec#ignoring-warnings).

    Example:

    ```hcl
    resource "aws_security_group_rule" "my-rule" {
        type = "ingress"
        cidr_blocks = ["0.0.0.0/0"] #tfsec:ignore:AWS006
    }
    ```

### terraform_validate

1. `terraform_validate` supports custom arguments so you can pass supported no-color or json flags.

    Example:

    ```yaml
    hooks:
      - id: terraform_validate
        args: ['--args=-json']
    ```

    In order to pass multiple args, try the following:

    ```yaml
     - id: terraform_validate
       args:
          - '--args=-json'
          - '--args=-no-color'
    ```

2. `terraform_validate` also supports custom environment variables passed to the pre-commit runtime

    Example:

    ```yaml
    hooks:
      - id: terraform_validate
        args: ['--envs=AWS_DEFAULT_REGION="us-west-2"']
    ```

    In order to pass multiple args, try the following:

    ```yaml
     - id: terraform_validate
       args:
          - '--envs=AWS_DEFAULT_REGION="us-west-2"'
          - '--envs=AWS_ACCESS_KEY_ID="anaccesskey"'
          - '--envs=AWS_SECRET_ACCESS_KEY="asecretkey"'
    ```

3. It may happen that Terraform working directory (`.terraform`) already exists but not in the best condition (eg, not initialized modules, wrong version of Terraform, etc). To solve this problem you can find and delete all `.terraform` directories in your repository using this command:

    ```shell
    find . -type d -name ".terraform" -print0 | xargs -0 rm -r
    ```

   `terraform_validate` hook will try to reinitialize them before running `terraform validate` command.

## Notes for contributors

1. Python hooks are supported now too. All you have to do is:
    1. add a line to the `console_scripts` array in `entry_points` in `setup.py`
    2. Put your python script in the `pre_commit_hooks` folder

Enjoy the clean, valid, and documented code!

### Run and debug hooks locally

```bash
pre-commit try-repo {-a} /path/to/local/pre-commit-terraform/repo {hook_name}
```

I.e.

```bash
pre-commit try-repo /mnt/c/Users/tf/pre-commit-terraform terraform_fmt # Run only `terraform_fmt` check
pre-commit try-repo -a ~/pre-commit-terraform # run all existing checks from repo
```

Running `pre-commit` with `try-repo` ignores all arguments specified in `.pre-commit-config.yaml`.

## Authors

This repository is managed by [Anton Babenko](https://github.com/antonbabenko) with help from [these awesome contributors](https://github.com/antonbabenko/pre-commit-terraform/graphs/contributors).

## License

MIT licensed. See LICENSE for full details.