当程序集和调用应用程序具有相同依赖项的不同版本时，AssemblyLoadContext 和依赖项解析

问题描述 投票：0回答：1

我相信我已经用尽了与该主题相关的答案和评论。 我用来演示该问题的项目的完整源代码可以在这里找到：https://github.com/jchristn/DependencyExample

假设有一个包含三个项目的解决方案。 第一个是依赖 RestWrapper v3.0.19 的控制台应用程序 (

Runner
)。 第二个是依赖 RestWrapper v3.0.20 的类库 (
Module1
)。 第三个是类库（
Module2
），依赖于 RestWrapper v3.0.18.

所有这三个都尝试对在 

Runner
中检索到的用户指定的 URL 执行 HTTP GET。 
Runner
然后使用 
AssemblyLoadContext
、
LoadFromAssemblyPath
、
Resolving
和 
Activator.CreateInstance
创建并调用 
Process
中的 
Runner1
方法，然后使用 
Runner2
，执行相同的 HTTP GET，例如

实例化模块

AssemblyLoadContext ctx1 = new AssemblyLoadContext("module1", false);
Assembly asm1 = ctx1.LoadFromAssemblyPath(Path.GetFullPath("module1/Module1.dll"));

ctx1.Resolving += (ctx, assemblyName) =>
{
    Console.WriteLine("| Module 1 loading assembly " + assemblyName.FullName);
    var parts = assemblyName.FullName.Split(',');
    string name = parts[0];
    var version = Version.Parse(parts[1].Split('=')[1]);
    string filename = new FileInfo(Path.GetFullPath("module1/" + name + ".dll")).FullName;
    Console.WriteLine("| Module 1 loading from file " + filename);

    Assembly asm = Assembly.LoadFrom(filename);
    Console.WriteLine("| Module 1 loaded assembly " + filename);
    return asm;
};

Type type1 = asm1.GetType("Module1.Processor", true);
dynamic instance1 = Activator.CreateInstance(type1);
instance1.Process(url);

简单的 RESTful 请求

using (RestRequest req = new RestRequest(url))
{
    using (RestResponse resp = req.Send())
    {
        Console.WriteLine("| Status (runner) : " + resp.StatusCode + " " + resp.ContentLength + " bytes");
    }
}

我可以确认这些文件确实存在：

C:\Code\Misc\DependencyExample\Runner\bin\Debug\net8.0>dir module1
 Volume in drive C is OS
 Volume Serial Number is 541C-D54E

 Directory of C:\Code\Misc\DependencyExample\Runner\bin\Debug\net8.0\module1

05/24/2024  08:22 AM    <DIR>          .
05/24/2024  08:22 AM    <DIR>          ..
05/24/2024  08:17 AM            37,648 Module1.deps.json
05/24/2024  08:17 AM             4,608 Module1.dll
05/24/2024  08:17 AM            10,548 Module1.pdb
05/20/2024  10:26 PM            29,184 RestWrapper.dll
05/20/2024  10:12 PM            11,776 Timestamps.dll
               5 File(s)         93,764 bytes
               2 Dir(s)  51,069,906,944 bytes free

C:\Code\Misc\DependencyExample\Runner\bin\Debug\net8.0>dir module2
 Volume in drive C is OS
 Volume Serial Number is 541C-D54E

 Directory of C:\Code\Misc\DependencyExample\Runner\bin\Debug\net8.0\module2

05/24/2024  08:22 AM    <DIR>          .
05/24/2024  08:22 AM    <DIR>          ..
05/24/2024  08:17 AM            37,648 Module2.deps.json
05/24/2024  08:17 AM             4,608 Module2.dll
05/24/2024  08:17 AM            10,548 Module2.pdb
05/20/2024  10:26 PM            29,184 RestWrapper.dll
05/20/2024  10:12 PM            11,776 Timestamps.dll
               5 File(s)         93,764 bytes
               2 Dir(s)  51,069,906,944 bytes free


Module1
和
Module2
在其
.csproj
中都有条目，用于将依赖文件复制到输出目录中：

<CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
<PublishSingleFile>true</PublishSingleFile>
<SelfContained>true</SelfContained>

我的操作假设是，通过将它们加载到具有自己的 

AssemblyLoadContext
功能的单独 
Resolving
中，他们将能够加载这些不同的版本，但在尝试运行时会失败并出现 
System.IO.FileLoadException: Could not load file or assembly 'RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null'. Could not find or load a specific file. (0x80131621)
异常
Runner1
。

控制台输出

C:\Code\Misc\DependencyExample\Runner\bin\Debug\net8.0>runner

URL: https://www.google.com
| Status (runner) : 200 57841 bytes
| Module 1 loading assembly RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null
| Module 1 loading from file C:\Code\Misc\DependencyExample\Runner\bin\Debug\net8.0\module1\RestWrapper.dll
System.IO.FileLoadException: Could not load file or assembly 'RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null'. Could not find or load a specific file. (0x80131621)
File name: 'RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null'
 ---> System.IO.FileLoadException: Could not load file or assembly 'RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null'.
   at System.Runtime.Loader.AssemblyLoadContext.LoadFromAssemblyPath(String assemblyPath)
   at System.Reflection.Assembly.LoadFrom(String assemblyFile)
   at DependencyExample.Program.<>c.<Main>b__0_0(AssemblyLoadContext ctx, AssemblyName assemblyName) in C:\Code\Misc\DependencyExample\Runner\Program.cs:line 49
   at System.Runtime.Loader.AssemblyLoadContext.GetFirstResolvedAssemblyFromResolvingEvent(AssemblyName assemblyName)
   at System.Runtime.Loader.AssemblyLoadContext.ResolveUsingEvent(AssemblyName assemblyName)
   at System.Runtime.Loader.AssemblyLoadContext.ResolveUsingResolvingEvent(IntPtr gchManagedAssemblyLoadContext, AssemblyName assemblyName)
   at Module1.Processor.Process(String url)
   at System.Dynamic.UpdateDelegates.UpdateAndExecuteVoid2[T0,T1](CallSite site, T0 arg0, T1 arg1)
   at DependencyExample.Program.Main(String[] args) in C:\Code\Misc\DependencyExample\Runner\Program.cs:line 56

我已经在上面的链接上传了完整的源代码（故意省略了

.gitignore
）。 
bin/Debug/net8.0
和
Module1
的
Module2
输出被复制到
module1/
的
module2/
目录中的子目录
Runner
和
bin/Debug/net8.0
中。

此外，问题的另一个问题是我需要在 Ubuntu 和 Windows 上运行它。

任何帮助将不胜感激！

编辑1

我也尝试过使用

AssemblyDependencyResolver
（示例来自https://tsuyoshiushio.medium.com/understand-advanced-assembleloadcontext-with-c-16a9d0cfeae3和https://gist.github.com/TsuyoshiUshio/ 551cb0f71c704aca75209552af50fc7a#file-pluginloadcontext-cs），它可以工作，但是 
Runner
、
Module1
和 
Module2
中的所有三个都以某种方式加载相同版本的 
RestWrapper
依赖项，而不是打包在每个输出目录中的版本.

编辑2

要求将代码粘贴到此处。

Runner 中的 Program.cs

namespace DependencyExample
{
    using RestWrapper;
    using System;
    using System.IO;
    using System.Reflection;
    using System.Runtime.Loader;

    internal class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                Console.Write(Environment.NewLine + "URL: ");
                string url = Console.ReadLine();
                if (String.IsNullOrEmpty(url)) continue;

                try
                {
                    #region Local

                    using (RestRequest req = new RestRequest(url))
                    {
                        using (RestResponse resp = req.Send())
                        {
                            Console.WriteLine("| Status (runner) : " + resp.StatusCode + " " + resp.ContentLength + " bytes");
                        }
                    }

                    #endregion

                    #region Module1

                    PluginLoadContext ctx1 = new PluginLoadContext("module1/");
                    Assembly asm1 = ctx1.LoadFromAssemblyPath(Path.GetFullPath("module1/Module1.dll"));

                    ctx1.Resolving += (ctx, assemblyName) =>
                    {
                        Console.WriteLine("| Module 1 loading assembly " + assemblyName.FullName);
                        var parts = assemblyName.FullName.Split(',');
                        string name = parts[0];
                        var version = Version.Parse(parts[1].Split('=')[1]);
                        string filename = new FileInfo(Path.GetFullPath("module1/" + name + ".dll")).FullName;
                        Console.WriteLine("| Module 1 loading from file " + filename);

                        Assembly asm = Assembly.LoadFrom(filename);
                        Console.WriteLine("| Module 1 loaded assembly " + filename);
                        return asm;
                    };

                    Type type1 = asm1.GetType("Module1.Processor", true);
                    dynamic instance1 = Activator.CreateInstance(type1);
                    instance1.Process(url);

                    #endregion

                    #region Module2

                    PluginLoadContext ctx2 = new PluginLoadContext("module2/");
                    Assembly asm2 = ctx2.LoadFromAssemblyPath(Path.GetFullPath("module2/Module2.dll"));

                    ctx1.Resolving += (ctx, assemblyName) =>
                    {
                        Console.WriteLine("| Module 2 loading assembly " + assemblyName.FullName);
                        var parts = assemblyName.FullName.Split(',');
                        string name = parts[0];
                        var version = Version.Parse(parts[1].Split('=')[1]);
                        string filename = new FileInfo(Path.GetFullPath("module2/" + name + ".dll")).FullName;
                        Console.WriteLine("| Module 2 loading from file " + filename);

                        Assembly asm = Assembly.LoadFrom(filename);
                        Console.WriteLine("| Module 2 loaded assembly " + filename);
                        return asm;
                    };

                    Type type2 = asm2.GetType("Module2.Processor", true);
                    dynamic instance2 = Activator.CreateInstance(type2);
                    instance2.Process(url);

                    #endregion

                    Console.WriteLine("Finished URL " + url);
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                }
            }
        }
        private class PluginLoadContext : AssemblyLoadContext
        {
            private AssemblyDependencyResolver _Resolver;

            public PluginLoadContext(string baseDirectory)
            {
                _Resolver = new AssemblyDependencyResolver(Path.GetFullPath(baseDirectory));
            }

            protected override Assembly? Load(AssemblyName name)
            {
                Console.WriteLine("  | Loading assembly: " + name);
                string path = _Resolver.ResolveAssemblyToPath(name);
                if (path != null)
                {
                    return LoadFromAssemblyPath(path);
                }
                return null;
            }

            protected override IntPtr LoadUnmanagedDll(string name)
            {
                Console.WriteLine("  | Loading unmanaged assembly: " + name);
                string path = _Resolver.ResolveUnmanagedDllToPath(name);
                if (path != null)
                {
                    return LoadUnmanagedDllFromPath(path);
                }
                return IntPtr.Zero;
            }
        }
    }
}

Module1 中的Processor.cs

namespace Module1
{
    using RestWrapper;
    using System;

    public class Processor
    {
        public Processor()
        {

        }

        public void Process(string url)
        {
            using (RestRequest req = new RestRequest(url))
            {
                using (RestResponse resp = req.Send())
                {
                    Console.WriteLine("| Status (module1): " + resp.StatusCode + " " + resp.ContentLength + " bytes");
                }
            }
        }
    }
}

Module2 中的Processor.cs

namespace Module2
{
    using RestWrapper;
    using System;

    public class Processor
    {
        public Processor()
        {

        }

        public void Process(string url)
        {
            using (RestRequest req = new RestRequest(url))
            {
                using (RestResponse resp = req.Send())
                {
                    Console.WriteLine("| Status (module2): " + resp.StatusCode + " " + resp.ContentLength + " bytes");
                }
            }
        }
    }
}
c# system.reflection activator
1个回答
0
投票

我认为问题在于您正在使用 Assembly.LoadFrom 加载依赖项（在 AssemblyLoadContext.Resolving 事件处理程序内）。由于其行为而失败。

我认为正确的方法是调用 AssemblyLoadContext.LoadFromAssemblyPath 方法。

ctx1.Resolving += (ctx, assemblyName) =>
{
    Console.WriteLine("| Module 1 loading assembly " + assemblyName.FullName);
    var parts = assemblyName.FullName.Split(',');
    string name = parts[0];
    var version = Version.Parse(parts[1].Split('=')[1]);
    string filename = new FileInfo(Path.GetFullPath("module1/" + name + ".dll")).FullName;
    Console.WriteLine("| Module 1 loading from file " + filename);

    //Assembly asm = Assembly.LoadFrom(filename); This line is replaced with the one below
    Assembly asm = ctx.LoadFromAssemblyPath(filename);

    Console.WriteLine("| Module 1 loaded assembly " + filename);
    return asm;
};

同样适用于

ctx2
。请注意，加载 Module2 时，您仍然使用 
ctx1
而不是 
ctx2
，因此这也需要修复。

AssemblyLoadContext ctx2 = new AssemblyLoadContext("module2", false);
Assembly asm2 = ctx2.LoadFromAssemblyPath(Path.GetFullPath("module2/Module2.dll")); // Replaced ctx1 with ctx2

ctx2.Resolving += (ctx, assemblyName) => // Replaced ctx1 with ctx2
{
    Console.WriteLine("| Module 2 loading assembly " + assemblyName.FullName);
    var parts = assemblyName.FullName.Split(',');
    string name = parts[0];
    var version = Version.Parse(parts[1].Split('=')[1]);
    string filename = new FileInfo(Path.GetFullPath("module2/" + name + ".dll")).FullName;
    Console.WriteLine("| Module 2 loading from file " + filename);

    //Assembly asm = Assembly.LoadFrom(filename); This line is replaced with the one below
    Assembly asm = ctx.LoadFromAssemblyPath(filename);

    Console.WriteLine("| Module 2 loaded assembly " + filename);
    return asm;
};
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