Add .NET Core container debugging support

docs/content/en/docs/workflows/debug.md

@@ -30,6 +30,7 @@ Debugging is currently supported for:
   - NodeJS (runtime ID: `nodejs`)
   - Java and JVM languages (runtime ID: `jvm`)
   - Python (runtime ID: `python`)
+  - .NET Core (runtime ID: `netcore`)
 
 Note that many debuggers may require additional information for the location of source files.
 We are looking for ways to identify this information and to pass it back if found.
@@ -101,6 +102,53 @@ The DAP is supported by Visual Studio Code, [Eclipse LSP4e](https://projects.ecl
 [and other editors and IDEs](https://microsoft.github.io/debug-adapter-protocol/implementors/tools/).
 DAP is not yet supported by JetBrains IDEs like PyCharm.
 
+#### .NET Core
+
+.NET Core applications are configured to be deployed along with `vsdbg`.
+
+In order to configure your application for debugging, your app must be:
+
+- Identified as being dotnet-based by having an entrypoint using [dotnet](https://github.com/dotnet/sdk) cli
+  or one of the following environment variables `ASPNETCORE_URLS`, `DOTNET_RUNNING_IN_CONTAINER`,
+  `DOTNET_SYSTEM_GLOBALIZATION_INVARIANT`.
+- Built with the `--configuration Debug` options to disable optimizations.
+
+**Note for users of [VS Code's debug adapter for C#](https://github.com/OmniSharp/omnisharp-vscode):**
+the following configuration can be used to debug a container. It assumes that your code is deployed
+in `/app` or `/src` folder in the container. If that is not the case, the `sourceFileMap` property
+should be changed to match the correct folder. `processId` is usually 1 but might be different if you
+have an unusual entrypoint. You can also use `"${command:pickRemoteProcess}"` instead if supported by
+your base image.  (`//` comments must be stripped.)
+```json
+{
+    "name": "Skaffold Debug",
+    "type": "coreclr",
+    "request": "attach",
+    "processId" : 1, 
+    "justMyCode": true, // set to `true` in debug configuration and `false` in release configuration
+    "pipeTransport": {
+        "pipeProgram": "kubectl",
+        "pipeArgs": [
+            "exec",
+            "-i",
+            "<NAME OF YOUR POD>", // name of the pod you debug.
+            "--"
+        ],
+        "pipeCwd": "${workspaceFolder}",
+        "debuggerPath": "/dbg/netcore/vsdbg", // location where vsdbg binary installed.
+        "quoteArgs": false
+    },
+    "sourceFileMap": {
+        // Change this mapping if your app in not deployed in /src or /app in your docker image
+        "/src": "${workspaceFolder}",
+        "/app": "${workspaceFolder}"
+        // May also be like this, depending of your repository layout
+        // "/src": "${workspaceFolder}/src",
+        // "/app": "${workspaceFolder}/src/<YOUR PROJECT TO DEBUG>"
+    }
+}
+```
+
 ## IDE Support via Events and Metadata
 
 `debug` provides additional support for IDEs to detect the debuggable containers and to determine

integration/debug_test.go

@@ -39,19 +39,19 @@ func TestDebug(t *testing.T) {
 		{
 			description: "kubectl",
 			deployments: []string{"java"},
-			pods:        []string{"nodejs", "npm", "python3", "go"},
+			pods:        []string{"nodejs", "npm", "python3", "go", "netcore"},
 		},
 		{
 			description: "kustomize",
 			args:        []string{"--profile", "kustomize"},
 			deployments: []string{"java"},
-			pods:        []string{"nodejs", "npm", "python3", "go"},
+			pods:        []string{"nodejs", "npm", "python3", "go", "netcore"},
 		},
 		{
 			description: "buildpacks",
 			args:        []string{"--profile", "buildpacks"},
 			deployments: []string{"java"},
-			pods:        []string{"nodejs", "npm", "python3", "go"},
+			pods:        []string{"nodejs", "npm", "python3", "go", "netcore"},
 		},
 	}
 	for _, test := range tests {

integration/testdata/debug/.gitignore

@@ -1,2 +1,4 @@
 node_modules
 *.swp
+netcore/**/obj
+netcore/**/bin

integration/testdata/debug/kustomization.yaml

@@ -4,3 +4,4 @@ resources:
   - npm/k8s/pod.yaml
   - python3/k8s/pod.yaml
   - go/k8s/pod.yaml
+  - netcore/k8s/pod.yaml

integration/testdata/debug/netcore/Dockerfile

@@ -0,0 +1,23 @@
+# See https://aka.ms/containerfastmode to understand how Visual Studio uses this Dockerfile
+# to build your images for faster debugging.
+
+FROM mcr.microsoft.com/dotnet/core/aspnet:3.1-buster-slim AS base
+WORKDIR /app
+EXPOSE 80
+EXPOSE 443
+
+FROM mcr.microsoft.com/dotnet/core/sdk:3.1-buster AS build
+COPY ["src/HelloWorld/HelloWorld.csproj", "src/HelloWorld/"]
+RUN dotnet restore "src/HelloWorld/HelloWorld.csproj"
+COPY . .
+WORKDIR "/src/HelloWorld"
+RUN ls -al 
+RUN dotnet build "HelloWorld.csproj" --configuration Debug -o /app/build
+
+FROM build AS publish
+RUN dotnet publish "HelloWorld.csproj" --configuration Debug -o /app/publish
+
+FROM base AS final
+WORKDIR /app
+COPY --from=publish /app/publish .
+ENTRYPOINT ["dotnet", "HelloWorld.dll"]

integration/testdata/debug/netcore/k8s/pod.yaml

@@ -0,0 +1,26 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: netcore
+spec:
+  containers:
+  - name: dotnet-web
+    image: skaffold-debug-netcore
+    ports:
+      - name: http
+        containerPort: 80
+        protocol: TCP
+    livenessProbe:
+      httpGet:
+        path: /
+        port: http
+      initialDelaySeconds: 5
+      failureThreshold: 4
+      timeoutSeconds: 5
+    readinessProbe:
+      httpGet:
+        path: /
+        port: http
+      initialDelaySeconds: 5
+      failureThreshold: 30
+      timeoutSeconds: 5

integration/testdata/debug/netcore/src/HelloWorld/Controllers/HomeController.cs

@@ -0,0 +1,15 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace HelloWorld.Controllers
+{
+    [ApiController]
+    [Route("/")]
+    public class HomeController : ControllerBase
+    {
+        [HttpGet]
+        public string Get()
+        {
+            return "Ok";
+        }
+    }
+}

integration/testdata/debug/netcore/src/HelloWorld/HelloWorld.csproj

@@ -0,0 +1,7 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+  </PropertyGroup>
+
+</Project>

integration/testdata/debug/netcore/src/HelloWorld/Program.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace HelloWorld
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            CreateHostBuilder(args).Build().Run();
+        }
+
+        public static IHostBuilder CreateHostBuilder(string[] args) =>
+            Host.CreateDefaultBuilder(args)
+                .ConfigureWebHostDefaults(webBuilder =>
+                {
+                    webBuilder.UseStartup<Startup>();
+                });
+    }
+}

integration/testdata/debug/netcore/src/HelloWorld/Startup.cs

@@ -0,0 +1,39 @@
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+
+namespace HelloWorld
+{
+    public class Startup
+    {
+        public Startup(IConfiguration configuration)
+        {
+            Configuration = configuration;
+        }
+
+        public IConfiguration Configuration { get; }
+
+        // This method gets called by the runtime. Use this method to add services to the container.
+        public void ConfigureServices(IServiceCollection services)
+        {
+            services.AddControllers();
+        }
+
+        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
+        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
+        {
+            if (env.IsDevelopment())
+            {
+                app.UseDeveloperExceptionPage();
+            }
+
+            app.UseRouting();
+            app.UseEndpoints(endpoints =>
+            {
+                endpoints.MapControllers();
+            });
+        }
+    }
+}

integration/testdata/debug/netcore/src/HelloWorld/appsettings.json

@@ -0,0 +1,10 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  },
+  "AllowedHosts": "*"
+}

integration/testdata/debug/skaffold.yaml

@@ -15,6 +15,8 @@ build:
     context: python3
   - image: skaffold-debug-go
     context: go
+  - image: skaffold-debug-netcore
+    context: netcore
 
 deploy:
   kubectl:
@@ -24,6 +26,7 @@ deploy:
     - npm/k8s/pod.yaml
     - python3/k8s/pod.yaml
     - go/k8s/pod.yaml
+    - netcore/k8s/pod.yaml
 
 profiles:
 - name: kustomize
@@ -54,3 +57,7 @@ profiles:
       context: go
       buildpacks:
         builder: "gcr.io/buildpacks/builder:v1"
+    - image: skaffold-debug-netcore
+      context: netcore
+      buildpacks:
+        builder: "gcr.io/buildpacks/builder:v1"

pkg/skaffold/debug/transform.go

@@ -71,7 +71,7 @@ import (
 type ContainerDebugConfiguration struct {
 	// Artifact is the corresponding artifact's image name used in the skaffold.yaml
 	Artifact string `json:"artifact,omitempty"`
-	// Runtime represents the underlying language runtime (`go`, `jvm`, `nodejs`, `python`)
+	// Runtime represents the underlying language runtime (`go`, `jvm`, `nodejs`, `python`, `netcore`)
 	Runtime string `json:"runtime,omitempty"`
 	// WorkingDir is the working directory in the image configuration; may be empty
 	WorkingDir string `json:"workingDir,omitempty"`

pkg/skaffold/debug/transform_netcore.go

@@ -0,0 +1,76 @@
+/*
+Copyright 2020 The Skaffold Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package debug
+
+import (
+	"strings"
+
+	"github.com/sirupsen/logrus"
+	v1 "k8s.io/api/core/v1"
+)
+
+type netcoreTransformer struct{}
+
+func init() {
+	containerTransforms = append(containerTransforms, netcoreTransformer{})
+}
+
+// isLaunchingNetcore determines if the arguments seems to be invoking dotnet
+func isLaunchingNetcore(args []string) bool {
+	if len(args) < 2 {
+		return false
+	}
+
+	if args[0] == "dotnet" || strings.HasSuffix(args[0], "/dotnet") {
+		return true
+	}
+
+	if args[0] == "exec" && (args[1] == "dotnet" || strings.HasSuffix(args[1], "/dotnet")) {
+		return true
+	}
+
+	return false
+}
+
+func (t netcoreTransformer) IsApplicable(config imageConfiguration) bool {
+	// Some official base images (eg: dotnet/core/runtime-deps) contain the following env vars
+	for _, v := range []string{"ASPNETCORE_URLS", "DOTNET_RUNNING_IN_CONTAINER", "DOTNET_SYSTEM_GLOBALIZATION_INVARIANT"} {
+		if _, found := config.env[v]; found {
+			return true
+		}
+	}
+
+	if len(config.entrypoint) > 0 && !isEntrypointLauncher(config.entrypoint) {
+		return isLaunchingNetcore(config.entrypoint)
+	}
+
+	if len(config.arguments) > 0 {
+		return isLaunchingNetcore(config.arguments)
+	}
+
+	return false
+}
+
+// Apply configures a container definition for vsdbg.
+// Returns a simple map describing the debug configuration details.
+func (t netcoreTransformer) Apply(container *v1.Container, config imageConfiguration, portAlloc portAllocator) (ContainerDebugConfiguration, string, error) {
+	logrus.Infof("Configuring %q for netcore debugging", container.Name)
+
+	return ContainerDebugConfiguration{
+		Runtime: "netcore",
+	}, "netcore", nil
+}