python-native-libs

Helpers for setting up an embedded Python interpreter

Overview

The canonical use case is to help set up ScalaPy to point to a specific Python installation by attempting to infer the correct configuration properties used by ScalaPy during the initialization of the embedded Python interpreter. This could potentially see usage outside of ScalaPy too since these properties are relevant to embedded Python in general.

Usage

By default Python checks for the python3 executable (or python if python3 is not found) on PATH

import ai.kien.python.Python

val python = Python()
// python: Python = ai.kien.python.Python@5eb35f5d

python.nativeLibrary
// res0: util.Try[String] = Success(value = "python3.9")

python.nativeLibraryPaths
// res1: util.Try[Seq[String]] = Success(
//   value = ArraySeq(
//     "/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib/python3.9/config-3.9-darwin",
//     "/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib"
//   )
// )

python.scalapyProperties
// res2: util.Try[Map[String, String]] = Success(
//   value = Map(
//     "jna.library.path" -> "/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib/python3.9/config-3.9-darwin:/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib",
//     "scalapy.python.library" -> "python3.9",
//     "scalapy.python.programname" -> "/usr/local/opt/[email protected]/bin/python3.9"
//   )
// )

python.ldflags
// res3: util.Try[Seq[String]] = Success(
//   value = ArraySeq(
//     "-L/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib/python3.9/config-3.9-darwin",
//     "-L/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib",
//     "-lpython3.9",
//     "-ldl",
//     "-framework",
//     "CoreFoundation"
//   )
// )

You can point it towards a specific Python installation by passing the path to the interpreter executable to Python

val python = Python("/usr/bin/python3")
// python: Python = ai.kien.python.Python@eb0b5d0

python.nativeLibrary
// res4: util.Try[String] = Success(value = "python3.9")

python.nativeLibraryPaths
// res5: util.Try[Seq[String]] = Success(
//   value = ArraySeq(
//     "/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib/python3.9/config-3.9-darwin",
//     "/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib"
//   )
// )

python.scalapyProperties
// res6: util.Try[Map[String, String]] = Success(
//   value = Map(
//     "jna.library.path" -> "/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib/python3.9/config-3.9-darwin:/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib",
//     "scalapy.python.library" -> "python3.9",
//     "scalapy.python.programname" -> "/usr/local/opt/[email protected]/bin/python3.9"
//   )
// )

python.ldflags
// res7: util.Try[Seq[String]] = Success(
//   value = ArraySeq(
//     "-L/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib/python3.9/config-3.9-darwin",
//     "-L/usr/local/opt/[email protected]/Frameworks/Python.framework/Versions/3.9/lib",
//     "-lpython3.9",
//     "-ldl",
//     "-framework",
//     "CoreFoundation"
//   )
// )

See docs/details.md to see the full list of these properties and what they mean.

scalapyProperties contains the system properties used by ScalaPy. For example, to set up ScalaPy to use the Python located at /usr/bin/python3 in Ammonite or Almond run

import $ivy.`ai.kien::python-native-libs:<version>`
import $ivy.`me.shadaj::scalapy-core:<scalapy_version>`

import ai.kien.python.Python

Python("/usr/bin/python3").scalapyProperties.fold(
  ex => println(s"Error while getting ScalaPy properties: $ex"),
  props => props.foreach { case(k, v) => System.setProperty(k, v) }
)

import me.shadaj.scalapy.py

println(py.module("sys").version)