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pyhcl

Implements a parser for HCL (HashiCorp Configuration Language) in Python. This implementation aims to be compatible with the original golang version of the parser.

pyhcl does not support HCL2 (which is what modern terraform uses). You might try https://pypi.org/project/python-hcl2/ instead (though I've never personally tried it).

The grammar and many of the tests/fixtures were copied/ported from the golang parser into pyhcl. All releases are tested with a variety of python versions from Python 2.7 onward.

This version has been modified to work with terraform 0.12 syntax. It should be backward compatible with earlier versions. It doesn't cover every situation. See discussion in pull request: #57

Installation

pip install pyhcl

Usage

This module is intended to be used in mostly the same way that one would use the json module in python, and load/loads/dumps are implemented.

import hcl

with open('file.hcl', 'r') as fp:
    obj = hcl.load(fp)

Currently the dumps function outputs JSON, and not HCL.

Convert HCL to JSON

pyhcl comes with a script that you can use to easily convert HCL to JSON, similar to the json.tool that comes with python:

hcltool INFILE [OUTFILE]

Structure Validation

Similar to JSON, the output of parsing HCL is a python dictionary with no defined structure. The golang library for HCL implements support for parsing HCL according to defined objects, but this implementation does not currently support such constructs.

Instead, I recommend that you use tools designed to validate JSON, such as the schematics library.

Syntax

  • Single line comments start with # or //
  • Multi-line comments are wrapped in /* and */
  • Values are assigned with the syntax key = value (whitespace doesn't matter). The value can be any primitive: a string, number, boolean, object, or list.
  • Strings are double-quoted and can contain any UTF-8 characters. Example: "Hello, World"
  • Numbers are assumed to be base 10. If you prefix a number with 0x, it is treated as a hexadecimal. If it is prefixed with 0, it is treated as an octal. Numbers can be in scientific notation: "1e10".
  • Boolean values: true, false
  • Arrays can be made by wrapping it in []. Example: ["foo", "bar", 42]. Arrays can contain primitives and other arrays, but cannot contain objects. Objects must use the block syntax shown below.

Objects and nested objects are created using the structure shown below:

variable "ami" {
    description = "the AMI to use"
}

Testing

To run the tests:

pip install -r testing-requirements.txt
tests/run_tests.sh

Debug Mode

To enable debug mode:

import hcl
hcl.parser.DEBUG = True

Authors

Dustin Spicuzza ([email protected])

Note: This project is not associated with Hashicorp