Add support for linux virtual environments

Author: glopesdev

src/Bonsai.Scripting.Python/EnvironmentHelper.cs

@@ -1,62 +1,105 @@
 using System;
 using System.IO;
-using System.Linq;
+using System.Runtime.InteropServices;
 using Python.Runtime;
 
 namespace Bonsai.Scripting.Python
 {
     static class EnvironmentHelper
     {
-        public static string GetPythonDLL(string path)
+        public static string GetPythonDLL(string pythonVersion)
         {
-            return Directory
-                .EnumerateFiles(path, searchPattern: "python3?*.*")
-                .Select(Path.GetFileNameWithoutExtension)
-                .Where(match => match.Length > "python3".Length)
-                .Select(match => match.Replace(".", string.Empty))
-                .FirstOrDefault();
+            return RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
+                ? $"python{pythonVersion.Replace(".", string.Empty)}.dll"
+                : $"libpython{pythonVersion}.so";
         }
 
         public static void SetRuntimePath(string pythonHome)
         {
-            var path = Environment.GetEnvironmentVariable("PATH", EnvironmentVariableTarget.Process).TrimEnd(Path.PathSeparator);
-            path = string.IsNullOrEmpty(path) ? pythonHome : pythonHome + Path.PathSeparator + path;
-            Environment.SetEnvironmentVariable("PATH", path, EnvironmentVariableTarget.Process);
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                var path = Environment.GetEnvironmentVariable("PATH", EnvironmentVariableTarget.Process).TrimEnd(Path.PathSeparator);
+                path = string.IsNullOrEmpty(path) ? pythonHome : pythonHome + Path.PathSeparator + path;
+                Environment.SetEnvironmentVariable("PATH", path, EnvironmentVariableTarget.Process);
+            }
+        }
+
+        public static string GetVirtualEnvironmentPath(string path)
+        {
+            if (string.IsNullOrEmpty(path))
+            {
+                path = Environment.GetEnvironmentVariable("VIRTUAL_ENV", EnvironmentVariableTarget.Process);
+                if (path == null) return path;
+            }
+
+            return Path.GetFullPath(path);
         }
 
-        public static string GetPythonHome(string path)
+        public static string GetPythonHome(string path, out string pythonVersion)
         {
+            var pythonHome = path;
+            pythonVersion = string.Empty;
             var configFileName = Path.Combine(path, "pyvenv.cfg");
             if (File.Exists(configFileName))
             {
                 using var configReader = new StreamReader(File.OpenRead(configFileName));
                 while (!configReader.EndOfStream)
                 {
                     var line = configReader.ReadLine();
-                    if (line.StartsWith("home"))
+                    static string GetConfigValue(string line)
                     {
                         var parts = line.Split('=');
-                        return parts[parts.Length - 1].Trim();
+                        return parts.Length > 1 ? parts[1].Trim() : string.Empty;
+                    }
+
+                    if (line.StartsWith("home"))
+                    {
+                        pythonHome = GetConfigValue(line);
+                    }
+                    else if (line.StartsWith("version"))
+                    {
+                        pythonVersion = GetConfigValue(line);
+                        if (!string.IsNullOrEmpty(pythonVersion))
+                        {
+                            pythonVersion = pythonVersion.Substring(0, pythonVersion.LastIndexOf('.'));
+                        }
                     }
                 }
             }
 
-            return path;
+            return pythonHome;
         }
 
-        public static string GetPythonPath(string pythonHome, string path)
+        public static string GetPythonPath(string pythonHome, string pythonVersion, string path)
         {
+            string sitePackages;
             var basePath = PythonEngine.PythonPath;
-            if (string.IsNullOrEmpty(basePath))
+            var baseDirectory = AppDomain.CurrentDomain.BaseDirectory;
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
             {
-                var pythonZip = Path.Combine(pythonHome, Path.ChangeExtension(Runtime.PythonDLL, ".zip"));
-                var pythonDLLs = Path.Combine(pythonHome, "DLLs");
-                var pythonLib = Path.Combine(pythonHome, "Lib");
-                var baseDirectory = AppDomain.CurrentDomain.BaseDirectory;
-                basePath = string.Join(Path.PathSeparator.ToString(), pythonZip, pythonDLLs, pythonLib, baseDirectory);
+                if (string.IsNullOrEmpty(basePath))
+                {
+                    var pythonZip = Path.Combine(pythonHome, Path.ChangeExtension(Runtime.PythonDLL, ".zip"));
+                    var pythonDLLs = Path.Combine(pythonHome, "DLLs");
+                    var pythonLib = Path.Combine(pythonHome, "Lib");
+                    basePath = string.Join(Path.PathSeparator.ToString(), pythonZip, pythonDLLs, pythonLib, baseDirectory);
+                }
+
+                sitePackages = Path.Combine(path, "Lib", "site-packages");
+            }
+            else
+            {
+                if (string.IsNullOrEmpty(basePath))
+                {
+                    var pythonBase = Path.GetDirectoryName(pythonHome);
+                    pythonBase = Path.Combine(pythonBase, "lib", $"python{pythonVersion}");
+                    var pythonLibDynload = Path.Combine(pythonBase, "lib-dynload");
+                    basePath = string.Join(Path.PathSeparator.ToString(), pythonBase, pythonLibDynload, baseDirectory);
+                }
+
+                sitePackages = Path.Combine(path, "lib", $"python{pythonVersion}", "site-packages");
             }
 
-            var sitePackages = Path.Combine(path, "Lib", "site-packages");
             return $"{basePath}{Path.PathSeparator}{path}{Path.PathSeparator}{sitePackages}";
         }
     }

src/Bonsai.Scripting.Python/RuntimeManager.cs

@@ -115,21 +115,15 @@ static void Initialize(string path)
         {
             if (!PythonEngine.IsInitialized)
             {
-                if (string.IsNullOrEmpty(path))
-                {
-                    path = Environment.GetEnvironmentVariable("VIRTUAL_ENV", EnvironmentVariableTarget.Process);
-                    if (string.IsNullOrEmpty(path)) path = Environment.CurrentDirectory;
-                }
-
-                path = Path.GetFullPath(path);
-                var pythonHome = EnvironmentHelper.GetPythonHome(path);
-                Runtime.PythonDLL = EnvironmentHelper.GetPythonDLL(pythonHome);
+                path = EnvironmentHelper.GetVirtualEnvironmentPath(path);
+                var pythonHome = EnvironmentHelper.GetPythonHome(path, out string pythonVersion);
+                Runtime.PythonDLL = EnvironmentHelper.GetPythonDLL(pythonVersion);
                 EnvironmentHelper.SetRuntimePath(pythonHome);
                 PythonEngine.PythonHome = pythonHome;
                 if (pythonHome != path)
                 {
                     var version = PythonEngine.Version;
-                    PythonEngine.PythonPath = EnvironmentHelper.GetPythonPath(pythonHome, path);
+                    PythonEngine.PythonPath = EnvironmentHelper.GetPythonPath(pythonHome, pythonVersion, path);
                 }
                 PythonEngine.Initialize();
             }