sg-tirith 1.0.0a1
Tirith simplifies defining Policy as Code.
License: Apache
Requires Python: >=3.8.*
Keywords: iac,policy,terraform,policy as code

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# Tirith (StackGuardian Policy Framework)

## A call for contributors

We are calling for contributors to help build out new features, review pull requests, fix bugs, and maintain overall code quality. If you're interested, please email us at team[at]stackguardian.io or get started by reading the [contributing.md](./CONTRIBUTING.md).

Tirith scans declarative Infrastructure as Code (IaC) configurations like Terraform against policies defined using JSON.

## Content

<!-- - [Feature Road-Map](#feature-road-map) -->
<!-- - [Local Development Environment](#local-development-environment) -->
- [Features](#features)
- [Usage](#usage)
- [Example Tirith policies](#example-tirith-policies)
- [Want to contribute?](#want-to-contribute)
  - [Getting an issue assigned](#getting-an-issue-assigned)
  - [A bug report](#a-bug-report)
  - [Opening a Pull Request and getting it merged](#opening-a-pull-request-and-getting-it-merged)
- [Submitting a feedback](#submitting-a-feedback)
- [Support](#support)
- [License](#license)

## Features

- An easy to read and simple way to define policy as code against structured formats.
- Use providers to define policies for terraform plan, infracost or any abstract JSON.
- Easily evaluate inputs against policy using pre-defined evaluators like ContainedIn, Equals, RegexMatch etc.
- Write your own provider (plugin) by leveraging a highly extensible and pluggable architecture to support any input formats.

<!-- ## Feature Road-map

This is only a list of approved features that will be included in Tirith over the next iterations.

- Extended support for Terraform Plan
- Support for Cloudformation and ARM
- Extended library of evaluator functions -->

## Usage
```
usage: tirith [-h] [-policy-path PATH] [-input-path SOURCE-TYPE] [--json] [--verbose] [--version]

Tirith (StackGuardian Policy Framework)

optional arguments:
  -h, --help               show this help message and exit
  -policy-path PATH        Path containing Tirith policy as code
  -input-path SOURCE-TYPE  Input file path
  --json                   Only print the result in JSON form (useful for passing output to other programs)
  --verbose                Show detailed logs of from the run
  --version                show program's version number and exit
```

## Example Tirith policies

[Examples using various providers](tests/providers)

1. VPC and EC2 instance policy (using Terraform plan provider)
- AWS VPC instance_tenancy is "default"
- EC2 instance cannot be destroyed

```json
{
  "meta": {
    "required_provider": "stackguardian/terraform_plan",
    "version": "v1"
  },
  "evaluators": [
    {
      "id": "check2",
      "provider_args": {
        "operation_type": "attribute",
        "terraform_resource_type": "aws_vpc",
        "terraform_resource_attribute": "instance_tenancy"
      },
      "condition": {
        "type": "Equals",
        "value": "default"
      }
    },
    {
      "provider_args": {
        "operation_type": "action",
        "terraform_resource_type": "aws_instance"
      },
      "condition": {
        "type": "ContainedIn",
        "value": ["destroy"]
      },
      "id": "destroy_ec2"
    }
  ],
  "eval_expression": "check_ec2_tags_are_present && !destroy_ec2"
}
```

2. Cost control policy (using Terraform plan provider)
- EC2 instance cost is lower than 100 USD per month

```json
{
  "meta": {
    "required_provider": "stackguardian/infracost",
    "version": "v1"
  },
  "evaluators": [
    {
      "provider_args": {
        "operation_type": "total_monthly_cost",
        "resource_type": ["aws_ec2"]
      },
      "condition": {
        "type": "LessThanEqualTo",
        "value": 100
      },
      "id": "ec2_cost_below_100_per_month"
    }
  ],
  "eval_expression": "ec2_cost_below_100_per_month"
}
```

3. StackGuardian Workflow Policy (using Terraform plan provider)
- Terraform Workflow should require an approval to create or destroy resources

```json
{
  "meta": {
    "required_provider": "stackguardian/sg_workflow",
    "version": "v1"
  },
  "evaluators": [
    {
      "provider_args": {
        "operation_type": "attribute",
        "workflow_attribute": "approvalPreApply"
      },
      "condition": {
        "type": "Equals",
        "value": true
      },
      "id": "require_approval_before_creating_ec2"
    }
  ],
  "eval_expression": "require_approval_before_creating_ec2"
}
```

<!-- ## Local Development Environment

- [Python 3.6 or higher](https://www.python.org/downloads/) is required.
- [pip](https://pip.pypa.io/en/stable/) is required. -->

<!-- ## Publish Package on test.pypi.org
* Use the following command to install the latest version of the setuptools package.
  ```
    python -m pip install --user --upgrade setuptools
  ```

* Make sure you are at the same directory where setup.py is located and run this command.
  ```
    python setup.py sdist
  ```
* Visit <a href="https://test.pypi.org/">test.pypi.org</a> and create a new account if not already.
* Install Twine package using following command.
  ```
    pip install twine
  ```
* Upload you package to test.pypi using following command.
  ```
    twine upload --repository-url https://test.pypi.org/legacy/ dist/*
  ``` -->

## Want to contribute?

If you're interested, please email us at team[at]stackguardian.io or get started by reading the [contributing.md](./CONTRIBUTING.md).

### Getting an issue assigned

Go to the <a href="https://github.com/StackGuardian/tirith">Tirith Repository</a> and in the <a href="https://github.com/stackguardian/tirith/issues">issues</a> tab describe any bug or feature you want to add. If found relevant, the maintainers will assign the issue to you and you may start working on it as mentioned in the next section.

<p>The kinds of issues a contributor can open:</p>
 <ul>
	<li>Report Bugs</li>
	<li>Feature Enhancement</li>
	<li>If any "help" is needed with using Tirith</li>
 </ul>

### A bug report

Head over to the <a href="https://github.com/StackGuardian/tirith">Tirith repository</a> and in the <a href="https://github.com/stackguardian/tirith/issues">issues</a> tab describe the bug you encountered and we will be happy to take a look into it.

### Opening a Pull Request and getting it merged?

1.  Go to the <a href ="https://github.com/StackGuardian/tirith">repository</a> and fork it.
2.  Clone the repository in your local machine.
3.  Open your terminal and `cd tirith`
4.  Create your own branch to work on the changes you intend to perform. For e.g. if you want some changes or bug fix to any function in the evaluators, name your branch with something relevant like, `git branch bug-fix-equals-evaluator`
5.  After necessary changes, `git push --set-upstream origin bug-fix-equals-evaluator`, `git checkout main` and `git merge bug-fix-equals-evaluator` or use the GUI to create a "Pull Request" after pushing it in the respective branch.
6.  A review request will be sent to the repository maintainers and your changes will be merged if found relevant.

## Submitting a Feedback

Wanna submit a feedback? It's as simple as writing and posting it in the <a href="https://github.com/StackGuardian/feedback/discussions/8">feedback section</a>.

<p>Your feedback will help us improve</p>

## Support

## License

<i>Apache License 2.0</i>

<p>The Apache License is a permissive free software license written by the Apache Software Foundation (ASF). It allows all users to use the software for any purpose, to distribute it, to modify it, and to distribute modified versions of the software under the terms of the license, without concern for royalties.</p>

# Changelog

All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [1.0.0-alpha.1] - 2022-10-04

- Initial realease of Tirith (StackGuardian Policy Framework)
- Adopted Covenant Code of Conduct
- cli wrapper for calling tirith


## Types of changes

**Added**: for new features.

**Changed**: for changes in existing functionality.

**Deprecated**: for soon-to-be removed features.

**Removed**: for now removed features.

**Fixed**: for any bug fixes.

**Security**: in case of vulnerabilities.

[unreleased]: https://github.com/StackGuardian/tirith/compare/1.0.0-alpha.1...HEAD
[1.0.0-alpha.1]: https://github.com/StackGuardian/tirith/compare/1.0.0-alpha.1