Getting started with .NET

This tutorial is intended for those new to building apps in the cloud, such as engineers and web developers, who want to learn key app development concepts as they apply to Google Cloud.

Objectives

For other language-specific tutorials for building your apps, see the following guides:

Costs

This tutorial uses the following billable components of Google Cloud:

The tutorial is designed to keep your resource usage within the limits of Google Cloud's Always Free tier. To generate a cost estimate based on your projected usage, use the pricing calculator. New Google Cloud users might be eligible for a free trial.

When you finish this tutorial, you can avoid continued billing by deleting the resources you created. For more information, see Cleaning up.

Before you begin

  1. Sign in to your Google Account.

    If you don't already have one, sign up for a new account.

  2. In the Cloud Console, on the project selector page, select or create a Cloud project.

    Go to the project selector page

  3. Make sure that billing is enabled for your Google Cloud project. Learn how to confirm billing is enabled for your project.

  4. To create a Firestore database in Native mode, complete the following steps:
    1. In the Cloud Console, go to the Firestore viewer page.
      Go to the Firestore viewer
    2. From the Select a Firestore mode screen, click Select Native Mode.
    3. Select a location for your Firestore database. This location setting is the default Google Cloud resource location for your Cloud project . This location is used for Google Cloud services in your Cloud project that require a location setting, specifically, your default Cloud Storage bucket and your App Engine app.
    4. Click Create Database.
  5. Enable the Cloud Run, Cloud Storage JSON, Cloud Logging, and Error Reporting APIs.

    Enable the APIs

  6. In Cloud Shell, open the app's source code.
    Go to Cloud Shell

    Cloud Shell provides command-line access to your Google Cloud resources directly from the browser.

  7. To download the sample code and change into the app directory, click Proceed.
  8. In Cloud Shell, configure the gcloud tool to use your new Google Cloud project:

    # Configure gcloud for your project
    gcloud config set project PROJECT_ID
    

    Replace PROJECT_ID with the Google Cloud project ID that you created using the Cloud Console.

    The gcloud command-line tool is the primary way you interact with your Google Cloud resources from the command line. In this tutorial, you use the gcloud tool to deploy and monitor your app.

Running your app

  1. Run the app:
    GOOGLE_CLOUD_PROJECT=PROJECT_ID dotnet run
    
    Replace PROJECT_ID with the Google Cloud project ID that you created.
  2. In Cloud Shell, click Web preview , and select Preview on port 8080. This opens a new window with your running app.

Deploying your app to Cloud Run

Google Cloud offers several options for running your code. For this example, you use Cloud Run to deploy a scalable app to Google Cloud. With zero server management, Cloud Run lets you focus on writing code. Plus, Cloud Run automatically scales to support sudden traffic spikes.

The Dockerfile tells Cloud Run how to run your app:

FROM mcr.microsoft.com/dotnet/core/aspnet:2.1
COPY . /app
WORKDIR /app
ENTRYPOINT ["dotnet", "Bookshelf.dll"]

Dockerfiles can be richer, but this configuration works for a lot of apps.

Cloud Run tells your app which port to listen to by setting the PORT environment variable. Bookshelf's Program.cs contains code to observe the PORT variable and listen on that port:

using Google.Cloud.Diagnostics.AspNetCore;
using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using System;

namespace Bookshelf
{
    public class Program
    {
        public static void Main(string[] args)
        {
            CreateWebHostBuilder(args).Build().Run();
        }

        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseGoogleDiagnostics(Startup.GetProjectId(), "Bookshelf", "0.01")
                .UseStartup<Startup>().UsePortEnvironmentVariable();
    }

    static class ProgramExtensions
    {
        // Google Cloud Run sets the PORT environment variable to tell this
        // process which port to listen to.
        public static IWebHostBuilder UsePortEnvironmentVariable(
            this IWebHostBuilder builder)
        {
            string port = Environment.GetEnvironmentVariable("PORT");
            if (!string.IsNullOrEmpty(port))
            {
                builder.UseUrls($"http://0.0.0.0:{port}");
            }
            return builder;
        }
    }
}

In your terminal window, deploy the app to Cloud Run using the gcloud tool:

  1. Build the app locally.
    dotnet publish -c Release
    
  2. Use Cloud Build to build a Docker container and publish to Container Registry.
    gcloud builds submit --tag gcr.io/PROJECT_ID/bookshelf \
        bin/Release/netcoreapp2.1/publish
    
  3. Run the container with Cloud Run (fully managed).
    gcloud run deploy bookshelf --region us-central1 --platform managed \
        --image gcr.io/PROJECT_ID/bookshelf --allow-unauthenticate
    
    Your app is now viewable at the URL displayed in the output of gcloud run:
    Service [bookshelf] revision [bookshelf-00001] has been deployed and is serving traffic at
    https://bookshelf-lwuhslogjlnpofsxugoc.a.run.app
    
  4. Copy the URL into your web browser to view the app. Bookshelf app homepage

For more information on deploying to Cloud Run, see the Cloud Run documentation.

Persisting your data with Firestore

You cannot store information on your Cloud Run instances, because it is lost if the instance is restarted, and doesn't exist when new instances are created. Instead, you use a database that all your instances read from and write to.

Google Cloud offers several options for storing your data. In this example, you use Firestore to store the data for each book. Firestore is a fully managed, serverless, NoSQL document database that lets you store and query data. Firestore auto scales to meet your app needs, and scales to zero when you're not using it. Add your first book now.

  1. To create a book for your deployed app, click Add book.

    Add a book to the Bookshelf app
  2. In the Title field, enter Moby Dick.
  3. In the Author field, enter Herman Melville.
  4. Click Save. There is now an entry to your Bookshelf app.

    Moby Dick Bookshelf app entry
  5. In the Cloud Console, go to Cloud Firestore. Go to Cloud Firestore

    The data appears in Firestore. The Bookshelf app stores each book as a Firestore document with a unique ID, and all these documents are stored in a Firestore collection. For the purposes of this tutorial, the collection is called books.

    Example of a Firestore document

Firestore stores the books by using the Firestore Client Library. Here is an example of fetching a Firestore document:

using Google.Cloud.Firestore;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Bookshelf.Models
{
    class FirestoreBookStore : IBookStore
    {
        private FirestoreDb _firestore;
        private CollectionReference _books;

        public FirestoreBookStore(string projectId)
        {
            _firestore = FirestoreDb.Create(projectId);
            _books = _firestore.Collection("Books");
        }

For more information on using Firestore, see Adding data to Firestore.

Storing file uploads in Cloud Storage

Now that you've added a book, it's time to add the book cover image. You cannot store files on your instances. A database isn't the right choice for image files. Instead, you use Cloud Storage.

Cloud Storage is the primary blob store for Google Cloud. You can use Cloud Storage to host app assets that you want to share across Google Cloud. To use Cloud Storage, you need to create a Cloud Storage bucket, a basic container to hold your data.

  1. In the Cloud Console, go to the Cloud Storage Browser page.

    Go to the Cloud Storage Browser page

  2. Click Create bucket.
  3. In the Create bucket dialog, enter a name for your bucket by appending your Google Cloud project ID to the string _bucket so the name looks like YOUR_PROJECT_ID_bucket. This name is subject to the bucket name requirements. All other fields can remain at their default values.
  4. Click Create.
  5. After your bucket is created, objects must be made publicly accessible to be viewed by users. To make your objects publicly accessible see Making Data Public.
  6. Click Edit book, and select an image to upload as your book's cover. For example, you can use this public domain image:
    Moby Dick book cover
  7. Click Save. You're redirected to the homepage, where there is an entry to your Bookshelf app.
    Moby Dick Bookshelf app entry

The bookshelf app sends uploaded files to Cloud Storage by using the Cloud Storage Client Library.

using Google.Cloud.Storage.V1;
using Microsoft.AspNetCore.Http;
using System;
using System.Threading.Tasks;
using System.Web;

namespace Bookshelf.Services
{
    public class ImageUploader
    {
        private readonly string _bucketName;
        private readonly StorageClient _storageClient;

        public ImageUploader(string bucketName)
        {
            _bucketName = bucketName;
            _storageClient = StorageClient.Create();
        }

For more information on using Cloud Storage, see the list of how-to guides.

Monitoring your app using Google Cloud's operations suite

You've deployed your app and created and modified books. To monitor these events for your users, use Application Performance Management.

Monitor logs with Cloud Logging

  1. In the Google Cloud, go to the Logs Viewer

    Go to Logs Viewer

    You can monitor your app in real time. If you have any issues with your app, this is one of the first places to look.

    Stackdriver Log Viewer
  2. In the Resource drop-down list, select Cloud Run Revision, bookshelf.

Monitor errors with Error Reporting

  1. In the Cloud Console, go to the Error Reporting page.
    Go to Error Reporting page
    Error Reporting highlights errors and exceptions in your app and lets you set up alerting around them.
  2. In your browser, go to the /Home/Throw URL in your app.
    For example, if your app is hosted at https://bookshelf-lwuhslogjlnpofsxugoc.a.run.app, then go to https://bookshelf-lwuhslogjlnpofsxugoc.a.run.app/Home/Throw.

    This generates a new test exception and sends it to Google Cloud's operations suite.

  3. In the Cloud Console, return to the Error Reporting page, and in a few moments the new error is visible. Click Auto Reload so you don't need to manually refresh the page.

    Error message from Error Reporting.

Cleaning up

To avoid incurring charges to your Google Cloud Platform account for the resources used in this tutorial:

Delete the project

  1. In the Cloud Console, go to the Manage resources page.

    Go to the Manage resources page

  2. In the project list, select the project that you want to delete and then click Delete .
  3. In the dialog, type the project ID and then click Shut down to delete the project.

What's next