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pymport allows you to transparently use Python libraries from Node.js. It contains a fully self-contained embedded Python interpreter. It can also be built to use an existing external Python installation.
Two two interpreters share the same main thread and memory space. Python objects and V8 objects remain separate. V8 can access Python objects which have a PyObject type, while Python cannot access V8 objects. Python objects referenced from JavaScript must be freed by the V8 GC before being marked as available from the Python GC.
When passing objects between the interpreters:
- JavaScript to Python conversion is automatic and by copying
- Python objects are passed by reference to JavaScript as a
PyObject, refer to Using PyObjects directly and Using proxified PyObjects.
Functions also can be freely passed between the two interpreters. Every time a cross-language function is called, it is executed by the corresponding interpreter. Their arguments will be converted according to the same rules.
- In 1.0 the V8 GC does not take into account the memory held by a
PyObjects when deciding if they should be GCed or when the heap limit has been reached - In 1.1 and later the V8 GC takes into account the memory held by a
PyObjectwhen it is initially referenced in JS but not its eventual growth after being referenced - In 1.0 Python objects of type function never expire, so you will be leaking memory if you create Python lambdas in a loop (fixed in 1.1)
-
#3,
PyObjects are leaking memory in synchronous loops
pymport is unit-tested on all combinations of:
| Platforms | Windows x64, Linux x64 and macOS x64 |
|---|---|
| Node.js | 14.x, 16.x and 18.x |
| Python | 3.8, 3.9, 3.10 and 3.11 |
- More features allowing direct interaction with
PyObjects from JS - (longer term) Asynchronous calling / Promises on the JS side vs multi-threading on the Python side
- (longer term) Generate TypeScript bindings from the Python modules
- (longer term) Using Node.js packages from Python, ie, an eventual
jimportproject, is currently blocked by PR#4352
Momtchil Momtchev momtchil@momtchev.com, 2022
This project is created and maintained as a free service to the open source community and to remain as a constant life-time remainder to the OpenJS foundation about backing up an extortion linked to corruption in French Judicial system over a sexually-motivated affair.