pythonnet/src/runtime/Util/PythonEnvironment.cs at v3.2.0-rc1 · pythonnet/pythonnet · GitHub

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using System;

using System.IO;

using System.Collections.Generic;

using System.Linq;

using System.Runtime.InteropServices;

using static System.FormattableString;

namespace Python.Runtime;

internal class PythonEnvironment

{

readonly static string PYDLL_ENV_VAR = "PYTHONNET_PYDLL";

readonly static string PYEXE_ENV_VAR = "PYTHONNET_PYEXE";

readonly static string PYNET_VENV_ENV_VAR = "PYTHONNET_VENV";

readonly static string VENV_ENV_VAR = "VIRTUAL_ENV";

public string? VenvPath { get; private set; }

public string? Home { get; private set; }

public Version? Version { get; private set; }

public string? ProgramName { get; set; }

public string? LibPython { get; set; }

public bool IsValid =>

!string.IsNullOrEmpty(ProgramName) && !string.IsNullOrEmpty(LibPython);

// TODO: Move the lib-guessing step to separate function, use together with

// PYTHONNET_PYEXE or a path lookup as last resort

// Initialize PythonEnvironment instance from environment variables.

// If PYTHONNET_PYEXE and PYTHONNET_PYDLL are set, these always have precedence.

// If PYTHONNET_VENV or VIRTUAL_ENV is set, we interpret the environment as a venv

// and set the ProgramName/LibPython accordingly. PYTHONNET_VENV takes precedence.

public static PythonEnvironment FromEnv()

{

var pydll = Environment.GetEnvironmentVariable(PYDLL_ENV_VAR);

var pydllSet = !string.IsNullOrEmpty(pydll);

var pyexe = Environment.GetEnvironmentVariable(PYEXE_ENV_VAR);

var pyexeSet = !string.IsNullOrEmpty(pyexe);

var pynetVenv = Environment.GetEnvironmentVariable(PYNET_VENV_ENV_VAR);

var pynetVenvSet = !string.IsNullOrEmpty(pynetVenv);

var venv = Environment.GetEnvironmentVariable(VENV_ENV_VAR);

var venvSet = !string.IsNullOrEmpty(venv);

PythonEnvironment? res = new();

if (pynetVenvSet)

res = FromVenv(pynetVenv) ?? res;

else if (venvSet)

res = FromVenv(venv) ?? res;

if (pyexeSet)

res.ProgramName = pyexe;

if (pydllSet)

res.LibPython = pydll;

return res;

}

public static PythonEnvironment? FromVenv(string path)

{

var env = new PythonEnvironment

{

VenvPath = path

};

string venvCfg = Path.Combine(path, "pyvenv.cfg");

if (!File.Exists(venvCfg))

return null;

var settings = TryParse(venvCfg);

if (!settings.ContainsKey("home"))

return null;

env.Home = settings["home"];

var pname = ProgramNameFromPath(path);

if (File.Exists(pname))

env.ProgramName = pname;

if (settings.TryGetValue("version", out string versionStr))

{

_ = Version.TryParse(versionStr, out Version versionObj);

env.Version = versionObj;

}

else if (settings.TryGetValue("version_info", out versionStr))

{

_ = Version.TryParse(versionStr, out Version versionObj);

env.Version = versionObj;

}

env.LibPython = FindLibPython(env.Home, env.Version);

return env;

}

private static Dictionary<string, string> TryParse(string venvCfg)

{

var settings = new Dictionary<string, string>();

string[] lines = File.ReadAllLines(venvCfg);

// The actually used format is really primitive: "<key> = <value>"

foreach (string line in lines)

{

var split = line.Split(new[] { '=' }, 2);

if (split.Length != 2)

continue;

settings[split[0].Trim()] = split[1].Trim();

}

return settings;

}

private static string? FindLibPython(string home, Version? maybeVersion)

{

// TODO: Check whether there is a .dll/.so/.dylib next to the executable

if (maybeVersion is Version version)

{

return FindLibPythonInHome(home, version);

}

return null;

}

private static string? FindLibPythonInHome(string home, Version version)

{

// Probe both — pyvenv.cfg's version field doesn't distinguish free-threaded.

var libPythonNames = new[]

{

GetDefaultDllName(version),

GetDefaultDllName(version, freeThreaded: true),

};

List<string> pathsToCheck = new();

if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))

{

var arch = RuntimeInformation.ProcessArchitecture;

if (arch == Architecture.X64 || arch == Architecture.Arm64)

{

// multilib systems

pathsToCheck.Add("../lib64");

}

pathsToCheck.Add("../lib");

}

else if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))

{

pathsToCheck.Add(".");

}

else

{

pathsToCheck.Add("../lib");

}

return pathsToCheck

.SelectMany(path => libPythonNames.Select(name => Path.Combine(home, path, name)))

.FirstOrDefault(File.Exists);

}

private static string ProgramNameFromPath(string path)

{

if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))

{

return Path.Combine(path, "Scripts", "python.exe");

}

else

{

return Path.Combine(path, "bin", "python");

}

internal static string GetDefaultDllName(Version version, bool freeThreaded = false)

{

string prefix = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "" : "lib";

string ftSuffix = freeThreaded ? "t" : "";

string suffix = RuntimeInformation.IsOSPlatform(OSPlatform.Windows)

? Invariant($"{version.Major}{version.Minor}{ftSuffix}")

: Invariant($"{version.Major}.{version.Minor}{ftSuffix}");

string ext = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? ".dll"

: RuntimeInformation.IsOSPlatform(OSPlatform.OSX) ? ".dylib"

: ".so";

return prefix + "python" + suffix + ext;

}

pythonnet/src/runtime/Util/PythonEnvironment.cs at v3.2.0-rc1 · pythonnet/pythonnet · GitHub

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