https://github.com/messense/rjsonnet-py
Python bindings to Rust jrsonnet crate(a Rust implementation of Jsonnet language)
https://github.com/messense/rjsonnet-py
jsonnet
Last synced: 6 months ago
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Python bindings to Rust jrsonnet crate(a Rust implementation of Jsonnet language)
- Host: GitHub
- URL: https://github.com/messense/rjsonnet-py
- Owner: messense
- License: mit
- Created: 2021-06-13T15:35:34.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2025-03-03T04:51:28.000Z (7 months ago)
- Last Synced: 2025-03-28T14:51:12.966Z (7 months ago)
- Topics: jsonnet
- Language: Rust
- Homepage:
- Size: 172 KB
- Stars: 10
- Watchers: 3
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# rjsonnet-py
[](https://pypi.org/project/rjsonnet)
Python bindings to Rust [jrsonnet](https://github.com/CertainLach/jrsonnet) crates (Rust implementation of Jsonnet language).
## Installation
```bash
pip install rjsonnet
```
## Usage
This module provides two functions:
1. `def evaluate_file(filename: str) -> str: ...`
2. `def evaluate_snippet(filename: str, src: str) -> str: ...`
In the latter case, the parameter `filename` is used in stack traces,
because all errors are given with the "filename" containing the code.
Keyword arguments to these functions are used to control the virtual machine. They are:
* `max_stack` (number)
* `gc_min_objects` (number, ignored)
* `gc_growth_trigger` (number, ignored)
* `ext_vars` (dict, string to string)
* `ext_codes` (dict, string to string)
* `tla_vars` (dict, string to string)
* `tla_codes` (dict, string to string)
* `max_trace` (number)
* `import_callback` (see example in [tests/](./tests/))
* `native_callbacks` (see example in [tests/](./tests/))
* `preserve_order` (bool, preserve object field order during manifestification)
* `gc` (bool, default: `True`, run garbage collection automatically)
The argument `import_callback` can be used to pass a callable, to trap the Jsonnet `import` and `importstr` constructs.
This allows, e.g., reading files out of archives or implementing library search paths.
The argument `native_callbacks` is used to allow execution of arbitrary Python code via `std.native(...)`.
This is useful so Jsonnet code can access pure functions in the Python ecosystem, such as compression, encryption, encoding, etc.
If an error is raised during the evaluation of the Jsonnet code, it is formed into a stack trace and thrown as a python `RuntimeError`.
```python
import rjsonnet
# evaluate a jsonnet file
rjsonnet.evaluate_file("filename.jsonnet")
# evalute a jsonnet code snippet
rjsonnet.evaluate_snippet('filename', 'jsonnet code snippet')
# Collect cyclic garbage in current thread created by jrsonnet
# to avoid memory leak, it's not necessary to call this function
# unless you have passed `gc=False` to `evaluate_file` or `evaluate_snippet`
rjsonnet.gc()
```
## License
This work is released under the MIT license. A copy of the license is provided in the [LICENSE](./LICENSE) file.