Hello world samples for Go, Node, and CSharp (#11)

* Add some hierachy

* Clone helloworld samples from serving

* add ignore files

* remove mac hidden files

* Finish readme

* Tweak formatting

* Update instructions

* Updating go

* Update yaml example

* Fix typo in service name.

* Update readme and yaml

* Update app yaml

* Ignore .vscode folder

* Fix missing newline at EOF

* Update sample to read env variable

.gitignore

@@ -0,0 +1 @@
+.DS_Store

serving/samples/helloworld-csharp/.gitignore

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+bin/
+obj/
+.vscode/

serving/samples/helloworld-csharp/Dockerfile

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+FROM microsoft/dotnet:2.1-sdk
+WORKDIR /app
+
+# copy csproj and restore as distinct layers
+COPY *.csproj ./
+RUN dotnet restore
+
+# copy and build everything else
+COPY . ./
+RUN dotnet publish -c Release -o out
+
+EXPOSE 8080
+
+ENTRYPOINT ["dotnet", "out/helloworld-csharp.dll"]

serving/samples/helloworld-csharp/Program.cs

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+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+
+namespace helloworld_csharp
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            CreateWebHostBuilder(args).Build().Run();
+        }
+
+        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
+            WebHost.CreateDefaultBuilder(args)
+                .UseStartup<Startup>().UseUrls("http://0.0.0.0:8080");
+    }
+}

serving/samples/helloworld-csharp/Properties/launchSettings.json

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+{
+  "iisSettings": {
+    "windowsAuthentication": false,
+    "anonymousAuthentication": true,
+    "iisExpress": {
+      "applicationUrl": "http://localhost:39053",
+      "sslPort": 44372
+    }
+  },
+  "profiles": {
+    "IIS Express": {
+      "commandName": "IISExpress",
+      "launchBrowser": true,
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "helloworld_csharp": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "applicationUrl": "https://localhost:5001;http://localhost:5000",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}

serving/samples/helloworld-csharp/README.md

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+# Hello World - .NET Core sample
+
+This sample application shows how to create a hello world application in C# using .NET Core 2.1.
+It reads in an env variable 'TARGET' and prints "Hello World: ${TARGET}!" if
+TARGET is not specified, it will use "NOT SPECIFIED" as the TARGET.
+
+## Prerequisites
+
+* You have a Kubernetes cluster with Knative installed. Follow the [installation instructions](https://github.com/knative/install/) if you need to do this.
+* You have installed and initalized [Google Cloud SDK](https://cloud.google.com/sdk/docs/) and have created a project in Google Cloud.
+* You have `kubectl` configured to connect to the Kubernetes cluster running Knative.
+* You have installed [.NET Core SDK 2.1](https://www.microsoft.com/net/core).
+
+## Steps to recreate the sample code
+
+While you can clone all of the code from this directory, hello world apps are generally more useful if you build them step-by-step. The following instructions recreate the source files from this folder.
+
+1. From the console, create a new empty web project using the dotnet command:
+
+    ```shell
+    dotnet new web -o helloworld-csharp
+    ```
+
+1. Update the `CreateWebHostBuilder` definition in `Program.cs` by adding `.UseUrls("http://0.0.0.0:8080")` to define the serving port:
+
+    ```csharp
+    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
+        WebHost.CreateDefaultBuilder(args)
+            .UseStartup<Startup>().UseUrls("http://0.0.0.0:8080");
+    ```
+
+1. Update the `app.Run(...)` statement in `Startup.cs` to read and return the TARGET environment variable:
+
+    ```csharp
+    app.Run(async (context) =>
+    {
+        var target = Environment.GetEnvironmentVariable("TARGET") ?? "NOT SPECIFIED";
+        await context.Response.WriteAsync($"Hello World: {target}");
+    });
+    ```
+
+1. In your project directory, create a file named `Dockerfile` and copy the code block below into it. For detailed instructions on dockerizing a .NET core app, see [dockerizing a .NET core app](https://docs.microsoft.com/en-us/dotnet/core/docker/docker-basics-dotnet-core#dockerize-the-net-core-application).
+
+    ```docker
+    FROM microsoft/dotnet:2.1-sdk
+    WORKDIR /app
+
+    # copy csproj and restore as distinct layers
+    COPY *.csproj ./
+    RUN dotnet restore
+
+    # copy and build everything else
+    COPY . ./
+    RUN dotnet publish -c Release -o out
+    ENTRYPOINT ["dotnet", "out/helloworld-csharp.dll"]
+    ```
+
+1. Create a new file, `app.yaml` and copy the following service definition into the file. Make sure to replace `{PROJECT_ID}` with the ID of your Google Cloud project. If you are using docker or another container registry instead, replace the entire image path.
+
+    ```yaml
+    apiVersion: serving.knative.dev/v1alpha1
+    kind: Service
+    metadata:
+      name: helloworld-python
+      namespace: default
+    spec:
+      runLatest:
+        configuration:
+          revisionTemplate:
+            spec:
+              container:
+                image: gcr.io/{PROJECT_ID}/helloworld-csharp
+                env:
+                - name: TARGET
+                  value: "C# Sample v1"
+    ```
+
+## Build and deploy this sample
+
+Once you have recreated the sample code files (or used the files in the sample folder) you're ready to build and deploy the sample app.
+
+1. For this example, we'll use Google Cloud Container Builder to build the sample into a container. To use container builder, execute the following gcloud command:
+
+    ```shell
+    gcloud container builds submit --tag gcr.io/${PROJECT_ID}/helloworld-csharp
+    ```
+
+1. After the build has completed, you can deploy the app into your cluster. Ensure that the container image value in `app.yaml` matches the container you build in the previous step. Apply the configuration using kubectl:
+
+    ```shell
+    kubectl apply -f app.yaml
+    ```
+
+1. Now that your service is created, Knative will perform the following steps:
+   * Create a new immutable revision for this version of the app.
+   * Network programming to create a route, ingress, service, and load balance for your app.
+   * Automatically scale your pods up and down (including to zero active pods).
+
+1. To find the URL and IP address for your service, use kubectl to list the ingress points in the cluster:
+
+    ```shell
+    kubectl get ing
+
+    NAME                        HOSTS                                       ADDRESS        PORTS     AGE
+    helloworld-csharp-ingress   helloworld-csharp.default.demo-domain.com   35.232.134.1   80        1m
+    ```
+
+1. Now you can make a request to your app to see the result. Replace `{IP_ADDRESS}` with the address you see returned in the previous step.
+
+    ```shell
+    curl -H "Host: helloworld-csharp.default.demo-domain.com" http://{IP_ADDRESS}
+    Hello World!
+    ```
+
+## Remove the sample app deployment
+
+To remove the sample app from your cluster, delete the service record:
+
+```shell
+kubectl delete -f app.yaml
+```

serving/samples/helloworld-csharp/Startup.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace helloworld_csharp
+{
+    public class Startup
+    {
+        // This method gets called by the runtime. Use this method to add services to the container.
+        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
+        public void ConfigureServices(IServiceCollection services)
+        {
+        }
+
+        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
+        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
+        {
+            if (env.IsDevelopment())
+            {
+                app.UseDeveloperExceptionPage();
+            }
+
+            app.Run(async (context) =>
+            {
+                var target = Environment.GetEnvironmentVariable("TARGET") ?? "NOT SPECIFIED";
+                await context.Response.WriteAsync($"Hello World: {target}");
+            });
+        }
+    }
+}

serving/samples/helloworld-csharp/app.yaml

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+apiVersion: serving.knative.dev/v1alpha1
+kind: Service
+metadata:
+  name: helloworld-csharp
+  namespace: default
+spec:
+  runLatest:
+    configuration:
+      revisionTemplate:
+        spec:
+          container:
+            image: gcr.io/{PROJECT_ID}/helloworld-csharp
+            env:
+            - name: TARGET
+              value: "C# Sample v1"

serving/samples/helloworld-csharp/helloworld-csharp.csproj

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+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Folder Include="wwwroot\" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.AspNetCore.App" />
+  </ItemGroup>
+
+</Project>

serving/samples/helloworld-go/Dockerfile

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+# Start from a Debian image with the latest version of Go installed
+# and a workspace (GOPATH) configured at /go.
+FROM golang
+
+# Copy the local package files to the container's workspace.
+ADD . /go/src/github.com/knative/docs/helloworld
+
+# Build the outyet command inside the container.
+# (You may fetch or manage dependencies here,
+# either manually or with a tool like "godep".)
+RUN go install github.com/knative/docs/helloworld
+
+# Run the outyet command by default when the container starts.
+ENTRYPOINT /go/bin/helloworld
+
+# Document that the service listens on port 8080.
+EXPOSE 8080

serving/samples/helloworld-go/README.md

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+# Hello World - Go
+
+A simple web app written in Go that you can use for testing.
+It reads in an env variable 'TARGET' and prints "Hello World: ${TARGET}!" if
+TARGET is not specified, it will use "NOT SPECIFIED" as the TARGET.
+
+## Prerequisites
+
+* You have a Kubernetes cluster with Knative installed. Follow the [installation instructions](https://github.com/knative/install/) if you need to do this. 
+* You have installed and initalized [Google Cloud SDK](https://cloud.google.com/sdk/docs/) and have created a project in Google Cloud.
+* You have `kubectl` configured to connect to the Kubernetes cluster running Knative.
+
+## Steps to recreate the sample code
+
+While you can clone all of the code from this directory, hello world
+apps are generally more useful if you build them step-by-step. The
+following instructions recreate the source files from this folder.
+
+1. Create a new file named `helloworld.go` and paste the following code. This code creates a basic web server which listens on port 8080:
+
+    ```go
+    package main
+
+    import (
+      "flag"
+      "fmt"
+      "log"
+      "net/http"
+      "os"
+    )
+
+    func handler(w http.ResponseWriter, r *http.Request) {
+      log.Print("Hello world received a request.")
+      target := os.Getenv("TARGET")
+      if target == "" {
+        target = "NOT SPECIFIED"
+      }
+      fmt.Fprintf(w, "Hello World: %s!\n", target)
+    }
+
+    func main() {
+      flag.Parse()
+      log.Print("Hello world sample started.")
+
+      http.HandleFunc("/", handler)
+      http.ListenAndServe(":8080", nil)
+    }
+    ```
+
+1. In your project directory, create a file named `Dockerfile` and copy the code block below into it. For detailed instructions on dockerizing a Go app, see [Deploying Go servers with Docker](https://blog.golang.org/docker).
+
+    ```docker
+    # Start from a Debian image with the latest version of Go installed
+    # and a workspace (GOPATH) configured at /go.
+    FROM golang
+
+    # Copy the local package files to the container's workspace.
+    ADD . /go/src/github.com/knative/docs/helloworld
+
+    # Build the helloworld command inside the container.
+    # (You may fetch or manage dependencies here,
+    # either manually or with a tool like "godep".)
+    RUN go install github.com/knative/docs/helloworld
+
+    # Run the helloworld command by default when the container starts.
+    ENTRYPOINT /go/bin/helloworld
+
+    # Document that the service listens on port 8080.
+    EXPOSE 8080
+    ```
+
+1. Create a new file, `app.yaml` and copy the following service definition into the file. Make sure to replace `{PROJECT_ID}` with the ID of your Google Cloud project. If you are using docker or another container registry instead, replace the entire image path.
+
+    ```yaml
+    apiVersion: serving.knative.dev/v1alpha1
+    kind: Service
+    metadata:
+      name: helloworld-go
+      namespace: default
+    spec:
+      runLatest:
+        configuration:
+          revisionTemplate:
+            spec:
+              container:
+                image: gcr.io/{PROJECT_ID}/helloworld-go
+                env:
+                - name: TARGET
+                  value: "Go Sample v1"
+    ```
+
+## Build and deploy this sample
+
+Once you have recreated the sample code files (or used the files in the sample folder) you're ready to build and deploy the sample app.
+
+1. For this example, we'll use Google Cloud Container Builder to build the sample into a container. To use container builder, execute the following gcloud command:
+
+    ```shell
+    gcloud container builds submit --tag gcr.io/${PROJECT_ID}/helloworld-go
+    ```
+
+1. After the build has completed, you can deploy the app into your cluster. Ensure that the container image value in `app.yaml` matches the container you build in the previous step. Apply the configuration using kubectl:
+
+    ```shell
+    kubectl apply -f app.yaml
+    ```
+
+1. Now that your service is created, Knative will perform the following steps:
+   * Create a new immutable revision for this version of the app.
+   * Network programming to create a route, ingress, service, and load balance for your app.
+   * Automatically scale your pods up and down (including to zero active pods).
+
+1. To find the URL and IP address for your service, use kubectl to list the ingress points in the cluster. You may need to wait a few seconds for the ingress point to be created, if you don't see it right away.
+
+    ```shell
+    kubectl get ing --watch
+
+    NAME                        HOSTS                                                                                   ADDRESS        PORTS     AGE
+    helloworld-go-ingress   helloworld-go.default.demo-domain.com,*.helloworld-go.default.demo-domain.com   35.232.134.1   80        1m
+    ```
+
+1. Now you can make a request to your app to see the result. Replace `{IP_ADDRESS}` with the address you see returned in the previous step.
+
+    ```shell
+    curl -H "Host: helloworld-go.default.demo-domain.com" http://{IP_ADDRESS}
+    Hello World: NOT SPECIFIED
+    ```
+    
+## Remove the sample app deployment
+
+To remove the sample app from your cluster, delete the service record:
+
+```shell
+kubectl delete -f app.yaml
+```

serving/samples/helloworld-go/app.yaml

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+apiVersion: serving.knative.dev/v1alpha1
+kind: Service
+metadata:
+  name: helloworld-go
+  namespace: default
+spec:
+  runLatest:
+    configuration:
+      revisionTemplate:
+        spec:
+          container:
+            image: gcr.io/{PROJECT_ID}/helloworld-go
+            env:
+            - name: TARGET
+              value: "Go Sample v1"

serving/samples/helloworld-go/helloworld.go

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+/*
+Copyright 2018 Google LLC
+
+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
+
+    https://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 main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+)
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	log.Print("Hello world received a request.")
+	target := os.Getenv("TARGET")
+	if target == "" {
+		target = "NOT SPECIFIED"
+	}
+	fmt.Fprintf(w, "Hello World: %s!\n", target)
+}
+
+func main() {
+	flag.Parse()
+	log.Print("Hello world sample started.")
+
+	http.HandleFunc("/", handler)
+	http.ListenAndServe(":8080", nil)
+}

serving/samples/helloworld-go/sample.yaml

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+# Copyright 2018 Google LLC
+#
+# 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
+#
+#     https://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.
+
+apiVersion: serving.knative.dev/v1alpha1
+kind: Configuration
+metadata:
+  name: configuration-example
+  namespace: default
+spec:
+  revisionTemplate:
+    metadata:
+      labels:
+        knative.dev/type: app
+    spec:
+      container:
+        # This is the Go import path for the binary to containerize
+        # and substitute here.
+        image: github.com/knative/serving/sample/helloworld
+        env:
+          - name: TARGET
+            value: shiniestnewestversion
+        readinessProbe:
+          httpGet:
+            path: /
+            port: 8080
+          initialDelaySeconds: 3
+          periodSeconds: 3
+---
+apiVersion: serving.knative.dev/v1alpha1
+kind: Route
+metadata:
+  name: route-example
+  namespace: default
+spec:
+  traffic:
+  - configurationName: configuration-example
+    percent: 100

serving/samples/helloworld-go/updated_configuration.yaml

@@ -0,0 +1,38 @@
+# Copyright 2018 Google LLC
+#
+# 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
+#
+#     https://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.
+
+apiVersion: serving.knative.dev/v1alpha1
+kind: Configuration
+metadata:
+  name: configuration-example
+  namespace: default
+spec:
+  revisionTemplate:
+    metadata:
+      labels:
+        knative.dev/type: app
+    spec:
+      container:
+        # This is the Go import path for the binary to containerize
+        # and substitute here.
+        image: github.com/knative/serving/sample/helloworld
+        env:
+          - name: TARGET
+            value: updatedversion
+        readinessProbe:
+          httpGet:
+            path: /
+            port: 8080
+          initialDelaySeconds: 3
+          periodSeconds: 3

serving/samples/helloworld-nodejs/.gitignore

@@ -0,0 +1 @@
+node_packages/

serving/samples/helloworld-nodejs/Dockerfile

@@ -0,0 +1,19 @@
+FROM node:8
+
+# Create app directory
+WORKDIR /usr/src/app
+
+# Install app dependencies
+# A wildcard is used to ensure both package.json AND package-lock.json are copied
+# where available (npm@5+)
+COPY package*.json ./
+
+RUN npm install --only=production
+# If you are building your code for production
+# RUN npm install --only=production
+
+# Bundle app source
+COPY . .
+
+EXPOSE 8080
+CMD [ "npm", "start" ]

serving/samples/helloworld-nodejs/README.md

@@ -0,0 +1,161 @@
+# Hello World - Node.js
+
+A simple web app in Node that you can use for testing.
+It reads in an env variable 'TARGET' and prints "Hello World: ${TARGET}!" if
+TARGET is not specified, it will use "NOT SPECIFIED" as the TARGET.
+
+## Prerequisites
+
+* You have a Kubernetes cluster with Knative installed. Follow the [installation instructions](https://github.com/knative/install/) if you need to do this.
+* You have installed and initalized [Google Cloud SDK](https://cloud.google.com/sdk/docs/) and have created a project in Google Cloud.
+* You have `kubectl` configured to connect to the Kubernetes cluster running Knative.
+* [Node.js](https://nodejs.org/en/) installed and configured.
+
+## Steps to recreate the sample code
+
+1. Create a new directory and initalize npm. You can accept the defaults, but change the entry point to app.js to be consistent with the sample code here.
+
+    ```shell
+    npm init
+
+    package name: (helloworld-nodejs) 
+    version: (1.0.0) 
+    description: 
+    entry point: (index.js) app.js
+    test command: 
+    git repository: 
+    keywords: 
+    author: 
+    license: (ISC) Apache-2.0
+    ```
+
+1. Install the `express` dependency:
+
+    ```shell
+    npm install express --save
+    ```
+
+1. Create a new file named 'app.js' and paste the following code:
+
+    ```js
+    const express = require('express');
+    const app = express();
+
+    app.get('/', function (req, res) {
+      console.log('Hello world received a request.');
+
+      var target = process.env.TARGET || 'NOT SPECIFIED';
+      res.send('Hello world: ' + target);
+    });
+
+    var port = 8080;
+    app.listen(port, function () {
+      console.log('Hello world listening on port',  port);
+    });
+    ```
+
+1. Modify the package.json file to add a start command to the scripts section:
+
+    ```json
+    {
+      "name": "knative-serving-helloworld",
+      "version": "1.0.0",
+      "description": "",
+      "main": "app.js",
+      "scripts": {
+        "start": "node app.js",
+        "test": "echo \"Error: no test specified\" && exit 1"
+      },
+      "author": "",
+      "license": "Apache-2.0"
+    }
+    ```
+
+1. In your project directory, create a file named `Dockerfile` and paste the following code. For detailed instructions on dockerizing a Node.js app, see [Dockerizing a Node.js web app](https://nodejs.org/en/docs/guides/nodejs-docker-webapp/).
+
+    ```docker
+    FROM node:8
+
+    # Create app directory
+    WORKDIR /usr/src/app
+
+    # Install app dependencies
+    # A wildcard is used to ensure both package.json AND package-lock.json are copied
+    # where available (npm@5+)
+    COPY package*.json ./
+
+    RUN npm install
+    # If you are building your code for production
+    # RUN npm install --only=production
+
+    # Bundle app source
+    COPY . .
+
+    EXPOSE 8080
+    CMD [ "npm", "start" ]
+    ```
+
+1. Create a new file, `app.yaml` and copy the following service definition into the file. Make sure to replace `{PROJECT_ID}` with the ID of your Google Cloud project. If you are using docker or another container registry instead, replace the entire image path.
+
+    ```yaml
+    apiVersion: serving.knative.dev/v1alpha1
+    kind: Service
+    metadata:
+      name: helloworld-nodejs
+      namespace: default
+    spec:
+      runLatest:
+        configuration:
+          revisionTemplate:
+            spec:
+              container:
+                image: gcr.io/{PROJECT_ID}/helloworld-nodejs
+                env:
+                - name: TARGET
+                  value: "Node.js Sample v1"
+    ```
+
+## Build and deploy this sample
+
+Once you have recreated the sample code files (or used the files in the sample folder) you're ready to build and deploy the sample app.
+
+1. For this example, we'll use Google Cloud Container Builder to build the sample into a container. To use container builder, execute the following gcloud command:
+
+    ```shell
+    gcloud container builds submit --tag gcr.io/${PROJECT_ID}/helloworld-nodejs
+    ```
+
+1. After the build has completed, you can deploy the app into your cluster. Ensure that the container image value in `app.yaml` matches the container you build in the previous step. Apply the configuration using kubectl:
+
+    ```shell
+    kubectl apply -f app.yaml
+    ```
+
+1. Now that your service is created, Knative will perform the following steps:
+   * Create a new immutable revision for this version of the app.
+   * Network programming to create a route, ingress, service, and load balance for your app.
+   * Automatically scale your pods up and down (including to zero active pods).
+
+1. To find the URL and IP address for your service, use kubectl to list the ingress points in the cluster. You may need to wait a few seconds for the ingress point to be created, if you don't see it right away.
+
+    ```shell
+    kubectl get ing --watch
+
+    NAME                        HOSTS                                       ADDRESS        PORTS     AGE
+    helloworld-nodejs-ingress   helloworld-nodejs.default.demo-domain.com   35.232.134.1   80        1m
+    ```
+
+1. Now you can make a request to your app to see the result. Replace `{IP_ADDRESS}` with the address you see returned in the previous step.
+
+    ```shell
+    curl -H "Host: helloworld-nodejs.default.demo-domain.com" http://{IP_ADDRESS}
+    Hello World: NOT SPECIFIED
+    ```
+
+## Remove the sample app deployment
+
+To remove the sample app from your cluster, delete the service record:
+
+```shell
+kubectl delete -f app.yaml
+```

serving/samples/helloworld-nodejs/app.js

@@ -0,0 +1,30 @@
+/*
+Copyright 2018 Google LLC
+
+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
+
+    https://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.
+*/
+
+const express = require('express');
+const app = express();
+
+app.get('/', function (req, res) {
+  console.log('Hello world received a request.');
+
+  var target = process.env.TARGET || 'NOT SPECIFIED';
+  res.send('Hello world: ' + target);
+});
+
+var port = 8080;
+app.listen(port, function () {
+  console.log('Hello world listening on port',  port);
+});

serving/samples/helloworld-nodejs/app.yaml

@@ -0,0 +1,15 @@
+apiVersion: serving.knative.dev/v1alpha1
+kind: Service
+metadata:
+  name: helloworld-nodejs
+  namespace: default
+spec:
+  runLatest:
+    configuration:
+      revisionTemplate:
+        spec:
+          container:
+            image: gcr.io/{PROJECT_ID}/helloworld-nodejs
+            env:
+            - name: TARGET
+              value: "Node.js Sample v1"

serving/samples/helloworld-nodejs/package-lock.json

@@ -0,0 +1,373 @@
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+  "lockfileVersion": 1,
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+    },
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+      "resolved": "https://registry.npmjs.org/array-flatten/-/array-flatten-1.1.1.tgz",
+      "integrity": "sha1-ml9pkFGx5wczKPKgCJaLZOopVdI="
+    },
+    "body-parser": {
+      "version": "1.18.2",
+      "resolved": "https://registry.npmjs.org/body-parser/-/body-parser-1.18.2.tgz",
+      "integrity": "sha1-h2eKGdhLR9hZuDGZvVm84iKxBFQ=",
+      "requires": {
+        "bytes": "3.0.0",
+        "content-type": "1.0.4",
+        "debug": "2.6.9",
+        "depd": "1.1.2",
+        "http-errors": "1.6.3",
+        "iconv-lite": "0.4.19",
+        "on-finished": "2.3.0",
+        "qs": "6.5.1",
+        "raw-body": "2.3.2",
+        "type-is": "1.6.16"
+      }
+    },
+    "bytes": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/bytes/-/bytes-3.0.0.tgz",
+      "integrity": "sha1-0ygVQE1olpn4Wk6k+odV3ROpYEg="
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+      "integrity": "sha1-DPaLud318r55YcOoUXjLhdunjLQ="
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+}

serving/samples/helloworld-nodejs/package.json

@@ -0,0 +1,23 @@
+{
+  "name": "knative-serving-helloworld",
+  "version": "1.0.0",
+  "description": "Simple hello world sample in Node",
+  "main": "app.js",
+  "scripts": {
+    "start": "node app.js",
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/knative/serving.git"
+  },
+  "author": "",
+  "license": "Apache-2.0",
+  "bugs": {
+    "url": "https://github.com/knative/serving/issues"
+  },
+  "homepage": "https://github.com/knative/serving#readme",
+  "dependencies": {
+    "express": "^4.16.3"
+  }
+}