https://github.com/open-policy-agent/rego-python

Python library for interacting with Rego ASTs.
https://github.com/open-policy-agent/rego-python

Last synced: 3 months ago
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Python library for interacting with Rego ASTs.

• Host: GitHub
• URL: https://github.com/open-policy-agent/rego-python
• Owner: open-policy-agent
• License: apache-2.0
• Created: 2018-06-28T22:54:19.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2021-07-15T18:21:36.000Z (over 3 years ago)
• Last Synced: 2024-08-04T21:07:11.661Z (6 months ago)
• Language: Python
• Size: 10.7 KB
• Stars: 47
• Watchers: 11
• Forks: 16
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-opa - Rego Python - Python package for interacting with Rego (Language and Platform Integrations / Python)

README

        
# rego-python

This repository contains a Python package for interacting with the [Open Policy Agent](https://github.com/open-policy-agent/opa) project's policy language: [Rego](https://www.openpolicyagent.org/docs/how-do-i-write-policies.html).

## Overview

module | description

--- | ---

`ast` | contains types representing Abstract Syntax Tree (AST) nodes in Rego.

`walk` | contains a visitor pattern implementation for `ast` types.

## Example: Load Rego AST from JSON

```python

import json

import requests

from rego import ast, walk

# Load some pi into OPA as data (yum!)

requests.put("http://localhost:8181/v1/data", data=json.dumps({

    "pi": 3.14,

}))

# Use OPA's Compile API to partially evaluate a query. Treat 'input.radius' as unknown.

resp = requests.post("http://localhost:8181/v1/compile", json.dumps({

    "query": "(data.pi * input.radius * 2) >= input.min_radius",

    "input": {

        "min_radius": 4,

    },

    "unknowns": ["input.radius"],

}))

# Load the resulting set of query ASTs out of the JSON response.

tree = resp.json()["result"]["queries"]

qs = ast.QuerySet.from_data(tree)

# Pretty print the ASTs.

walk.pretty_print(qs)

```

In a new terminal:

```

$ opa run --server

```

In another terminal, run the example.

```bash

$ git clone https://github.com/open-policy-agent/rego-python.git

$ cd rego-python

$ virtualenv env

$ source env/bin/activate

$ pip install -r example-requirements.txt

$ pip install -e .

$ python example.py

```

Example output.

```bash

QuerySet (1 queries)

  Query (1 exprs)

    Expr

      Term

        Ref

          Term

            Var(gte)

      Term

        Call

          Term

            Ref

              Term

                Var(mul)

          Term

            Call

              Term

                Ref

                  Term

                    Var(mul)

              Term

                Scalar(3.14)

              Term

                Ref

                  Term

                    Var(input)

                  Term

                    Scalar(radius)

          Term

            Scalar(2)

      Term

        Scalar(4)

```