WebApi with .NET Core

Samples and resources of how to design WebApi with .NET

• WebApi with .NET Core
  • Support
  • Prerequisites
  • Project Configuration
  • Routing
  • Route templates
    • Route parameters
    • Route constraints
  • Routing pipeline
  • Routing with endpoints
  • Routing with controllers
    • Conventional controllers routing
    • Routing with attributes
  • Links
  • REST
  • The Six Contraints of REST
    • Client-server
    • Stateless
    • Cacheable
    • Layered System
    • Code on demand
    • Uniform interface
    • Identification of resources
    • Manipulation of resources through representations
    • Self-descriptive messages
    • Hypermedia as the engine of application state (HATEOAS)
  • API Versioning
  • Filters
  • Middleware
  • Inversion of Control and Dependency Injection
  • API Testing
  • Projects structure
  • Logging
  • General
    • Log Levels
    • Log Categories
    • Log Scopes
    • Log Events
    • Links
  • Serilog
    • Links
  • NLog
    • Links
  • Elastic Stack - Kibana, LogStash etc.
    • Links
  • CorrelationId
    • Links
  • Docker
  • Sample DOCKERFILE
  • Debugging application inside Docker
  • Links
  • Storage
  • EntityFramework
  • Dapper
  • Azure
  • App Services
    • Links
  • Azure ARM Templates
    • Links
  • Azure Key Vault
    • Links
  • AWS
  • CI/CD
  • Azure DevOps Pipelines
    • Setting up Docker Resources
    • Building and pushing image to Docker Registry
    • Template for building and pushing Docker image
    • Azure Docker Registry
    • Docker Hub
    • Publishing application to App Services
    • Links
    • Links
  • Github Actions
    • Building and pushing image to Docker Registry
    • Docker Hub
      • Links
  • Caching
  • GraphQL
  • Links
  • CQRS
  • OAuth
  • Links

Support

Feel free to create an issue if you have any questions or request for more explanation or samples. I also take Pull Requests!

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👉 Github Sponsors

Prerequisites

1. Install .NET Core SDK 3.1 from link.
2. Install one of IDEs:
   • Visual Studio - link - for Windows only. Community edition is available for free,
   • Visual Studio for Mac - link - for MacOS only. Available for free,
   • Visual Studio Code- link with C# plugin - Cross-platform support. Available for free,
   • Rider - link - cross-platform support. Paid, but there are available free options (for OpenSource, students, user groups etc.)

Project Configuration

Routing

From the documentation: "Routing is responsible for matching incoming HTTP requests and dispatching those requests to the app's executable endpoints."

Saying differently routing is responsible for finding exact endpoint based on the request parameters - usually based on the URL pattern matching.

Endpoint executes the logic that creates an HTTP response based on request.

To use routing and endpoints it's needed to call

UseRouting

UseEndpoints

Startup.Configure

Note that those methods should be registered in the order as presented above. If the order is changed then it won't be registered properly.

Route templates

Templates add flexibility to supported URL definition.

The simplest option is static URL where you have just URL, eg: -

/Reservations/List

/GetUsers

/Orders/ByStatuses/Closed

Route parameters

Static URLs are fine for the list endpoints, but if we'd like to get a list of records.
To allow dynamic matching (eg. reservation by Id) we need to use parameters. They can be added using

{parameterName}

/Reservations/{id}

/users/{id}/orders/{orderId}

They don't need to be only used instead of concrete URL part. You can also do eg.: -

/Reservations?status={reservationStatus}&user={userId}

/Reservations?status=Open&userId=123

status

Open

userId

123

/Download/{fileName}.{extension}

/Download/testFile.txt

fileName

testFile

extension

txt

/Configuration/{entityType}Dictionary

/Configuration/OrderStatusDictionary

entityType

OrderStatus

You can also add catch-all parameters -

{**parameterName}

/Reservations/{id}/{**reservationPath}

/Reservations/123/changeStatus/confirmed

reservationPath

changeStatus/confirmed

It's also possible to make the parameter optional by adding

?

/Reservations/{id?}

/Reservations

/Reservation/123

Route constraints

Route template parameters can contain constraints to narrow down the matched results. To use it you need to add constraint name after parameter name

{prameter:constraintName}

/Reservations/{id:guid}

/Reservations/632863d2-5cbf-4c9f-92e1-749d264d965e

/Reservations/123

/Reservations/top/{limit:int:minlength(1):maxLength(10)

1

10

limit

/Inbox?from={fromEmailAddress:regex(\\[A-Z0-9._%+-][email protected][A-Z0-9.-]+\.[A-Z]{2,4})}

/[email protected]

fromEmailAddress

[email protected]

Note - failing constraint will result with

400 - BadRequest

You can also define your custom constraint. The sample use case would be when you want to provide the validation for your business id format.

See sample that validates if reservation id is built from 3 non-empty parts split by

|

public class ReservationIdConstraint : IRouteConstraint
{
    public bool Match(
        HttpContext httpContext,
        IRouter route,
        string routeKey,
        RouteValueDictionary values,
        RouteDirection routeDirection)
    {
        if (routeKey == null)
        {
            throw new ArgumentNullException(nameof(routeKey));
        }

    if (values == null)
    {
        throw new ArgumentNullException(nameof(values));
    }

    if (!values.TryGetValue(routeKey, out var value) && value != null)
    {
        return false;
    }

    var reservationId = Convert.ToString(value, CultureInfo.InvariantCulture);

    return reservationId.Split("|").Where(part => !string.IsNullOrWhiteSpace(part)).Count() == 3;
}
}

You need to register it in

Startup.ConfigureServices

AddRouting

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        // registers controllers in dependency injection container
        services.AddControllers();

    services.AddRouting(options =>
    {
        options.ConstraintMap.Add("reservationId", typeof(ReservationIdConstraint));
    });
}

// (...)
}

Then you can use it to in route: -

/Reservations/{id:reservationId}

/Reservations/RES|123|01

id

RES|123|01

/Reservations/123

Routing pipeline

Routing is split into the following steps: - request URL parsing - perform matching against registered routes (it's done in parallel, so the order of registration doesn't matter) - from matching routes, remove all that do not match routes constraints (eg. route parameter defined as int was not numeric) - select single best matching (the most concrete one) if possible, from the left routes. If there are still more than one matches - the exception is being thrown. If there was only single match but value does not match constraint then exception will be thrown.

Having eg. following routes:

• /Clients/List

• /Clients/{id}

• /Reservations/{id:alpha}

• /Reservations/{id:int}

• /Reservations/List

and trying to match

/Reservation/List

• /Reservations/{id:alpha}

• /Reservations/{id:int}

• /Reservations/List

It matched the

Reservations

{id}

List

List

Then constraints will be verified and we'll end up with two routes (as

{id:int}

List

• /Reservations/{id:alpha}

• /Reservations/List

From this set both are matching, but

List

Accordingly: - trying to match

Reservations/abcde

/Reservations/{id:alpha}

Reservations/123

/Reservations/{id:int}

Routing with endpoints

ASP.NET Core allows to define raw endpoints without the need to use controllers. They can be defined inside

UseEndpoints

UseGet

UsePost

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
    }

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    // registers routing in middleware pipeline
    app.UseRouting();

    // defines endpoints to be routed
    app.UseEndpoints(endpoints =>
    {
         endpoints.MapGet("/Reservations/{id}", async context =>
         {
             var name = context.Request.RouteValues["id"];
             await context.Response.WriteAsync($"Reservation with {id}!");
         });
    });
}
}

Using endpoints currently requires a lot of bare-bone code. This will change with .NET 5 where it will get a set of useful methods that will make it first-class citizen. See more in accepted API review: link.

Routing with controllers

Http requests can be mapped to controller with two ways: conventional and through attributes

Conventional controllers routing

Conventional is done by calling

MapControllerRoute

UseEndpoints

pattern

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
    }

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    // registers routing in middleware pipeline
    app.UseRouting();

    // defines endpoints to be routed
    app.UseEndpoints(endpoints =>
    {
        // defines concrete routing to single controller action
        endpoints.MapControllerRoute(name: "blog",
            pattern: "Reservations/{id}",
            defaults: new { controller = "Reservations", action = "Get" });

        // defines "catch-all" routing that will route all requests
        // matching `/Controller/Action` or `/Controller/Action/id`
        endpoints.MapControllerRoute(name: "default",
            pattern: "{controller=Home}/{action=Index}/{id?}");
    });
}
}

Important thing to note is controllers should have the

Controller

ReservationsController

Reservations

Routing with attributes

Controllers are derived from the MVC pattern concept. They are responsible for orchestration between requests (inputs) and models. Routing can be defined by putting attributes on top of method and controller definition.

If you want to use Controllers then you should also call

AddControlers

MapControllers

UseEndpoints

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        // registers controllers in dependency injection container
        services.AddControllers();
    }

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    // registers routing in middleware pipeline
    app.UseRouting();

    // defines endpoints to be routed
    app.UseEndpoints(endpoints =>
    {
        // maps controllers routes to endpoints
        endpoints.MapControllers();
    });
}
}

Route attribute

The most generic attribute is

[Route]

public class ReservationsController : Controller
{
    [Route("")]
    [Route("Reservations")]
    [Route("Reservations/List")]
    [Route("Reservations/List/{status?}")]
    public IActionResult List(string status)
    {
        //(...)
    }

[Route("Reservations/Summary")]
[Route("Reservations/Summary/{userId?}")]
public IActionResult Summary(int? userId)
{
    // (...)
}
}

In this example routes: -

/

/Reservations

/Reservations/List

/Reservations/List/Open

List

/Reservations/Summary

Reservations/Summary/123

Summary

Important note is that you should not use

action

area

controller

handler

page

/Reservations/{page}

HTTP methods attributes

ASP.NET Core provides also more specific attributes

[HttpGet]

[HttpPost]

[HttpPut]

[HttpDelete]

[HttpHead]

[HttpPatch]

[Route]

Sample of the most common CRUD controller definition:

[Route("api/[controller]")]
[ApiController]
public class ReservationsController : ControllerBase
{
    [HttpGet]
    public IActionResult List([FromQuery] string filter)
    {
        //(...)
    }

[HttpGet("{id}")]
public IActionResult Get(int id)
{
    // (...)
}

[HttpPost]
public IActionResult Create([FromBody] CreateReservation request)
{
    // (...)
}

[HttpPut("{id}")]
public IActionResult Put(int id, [FromBody] UpdateReservation request)
{
    // (...)
}

[HttpDelete("{id}")]
public IActionResult Delete(int id)
{
    // (...)
}
}

Using

[Route("api/[controller]")]

/api/Reservations

/api

[Route("api/[controller]/open")]

[controller]

[Route("api/reservations")]

Having that: -

GET /api/Reservations

List

filter

[FromQuery]

GET /api/Reservations?filter=open

open

GET /api/Reservations

null

GET /api/Reservations/123

Get

id

POST /api/Reservations/123

Create

request

[FromBody]

PUT /api/Reservations/123

Update

DELETE /api/Reservations/123

Delete

It's not mandatory to use route prefix. Most of the time it's useful, but when you have nesting inside the API then it's worth setting up it manually eg.

[ApiController]
public class UserReservationsController : ControllerBase
{
    [HttpGet("api/users/{userId}/reservations")]
    public IActionResult List(int userId, [FromQuery] string filter)
    {
        //(...)
    }

[HttpGet("api/users/{userId}/reservations/{id}")]
public IActionResult Get(int userId, int id)
{
    // (...)
}

[HttpPost("api/users/{userId}/reservations/{id}")]
public IActionResult Create(int userId, [FromBody] CreateReservation request)
{
    // (...)
}

[HttpPut("api/users/{userId}/reservations/{id}/status")]
public IActionResult Put(int userId, int id, [FromBody] UpdateReservationStatus request)
{
    // (...)
}
}

Links

• Microsoft Documentation - Routing in ASP.NET Core
• Microsoft Documentation - Routing to controller actions in ASP.NET Core
• DotNetMentors - http://dotnetmentors.com/mvc/explain-asp-net-mvc-routing-with-example.aspx
• StrathWeb - Dynamic controller routing in ASP.NET Core 3.0
• Andrew Lock - Accessing route values in endpoint middleware in ASP.NET Core 3.0

REST

Let's go back in time. In 2000 Roy Fielding wrote doctoral dissertation titled "Architectural Styles and the Design of Network-based Software Architectures". This dissertation gave rise to "REpresentational State Transfer" - REST. Roy created REST as an architectural style based on the principles that make the Internet so successful. The World Wide Web runs itself on HTTP, which has a number of conventions that provide the basis for scalability, fault tolerance, and loose coupling. REST and HTTP are not the same thing, but REST fully embraces HTTP. It means that it uses verbs, status codes, headers, and resource identified as URI in order to fulfill the constraints that together compose the so-called RESTful style. What are those constraints?

The Six Contraints of REST

REST, like any other architectural style, describes constraints, that composed together define the basis of RESTful style.

Client-server

This constraint just mainly specifies that there's a distinction between a client and a server. This separation allows the components to evolve independently thus improving portability and scalability.

Stateless

Each request must have all the information necessary for its correct completion. It means that all the state that's contained for a given web request is contained within the request itself as a part of the URI, query string parameters, body, or headers. Since there is no session related dependency, each server can handle any request thus API can be easily scaled. Removing all server-side state synchronization logic also makes REST APIs less complex.

Cacheable

The server should label what data within a response to a request can be cached and what cannot. If a response can be cached, then a client cache is given the rights to reuse that response data for later, equivalent requests. Following this constraint give the potential to partially or completely eliminate some interactions, thus improving performance and scalability and also decrease latency.

Layered System

The client can make a request and the response could come from a web server, a load balancer, a cache, etc. For the client, it doesn't really matter where the data is coming from as long as it gets the requested information. In other words, before the server completes the response, it can perform additional operations that the client does not need to know.

Code on demand

This is the only optional constraint. Most of the time, the server will be sending the static representations of resources in the form of XML or JSON, but on demand, it can send additional code (f.e. javascript) that can be executed on the client side. This simplifies clients by reducing the number of features required to be pre-implemented.

Uniform interface

The server should provide an API that will be well understood by all applications communicating with it. By designing one interface, we should respond to the needs of all applications that use it. In order to obtain such a uniform interface, four additional constraints must be met.

Identification of resources

On the basis of a single request, the server can identify the resource it concerns. For that purpose most often the Uniform Resource Identifier - URI is used. It distinguishes resource from any other, and through it interaction with that resource take place. In the example we have address that is pointing on specific employee with id 123. This address is the URI, which is identifier and the returned employee is the resource.

http
GET http://example.org/employees/123

http
200 OK
{
  "employeeId": 123,
  "firstName": "John",
  "lastName": "Doe"
}

Manipulation of resources through representations

The server can return reponse in various formats (media types) like HTML, XML, JSON etc. That format is the representation of the identified resource, that the client can understand and manipulate. It is possible for the client to request a specific representation that fits it needs. This is accomplished via the Accept header.

http
GET http://example.org/employees/123
Accept: application/xml

http
200 OK


    123
    John
    Doe

http
POST http://example.org/employees
Content-type: application/json
{
  "firstName": "John",
  "lastName": "Doe"
}

http
201 Created
Location: http://example.org/employees/123

Self-descriptive messages

A message, which is a request or a response, is being considered as self-descriptive when it contains all the information necessary to complete the task. In other words it should contains all the information that the recipient needs to understand it. Down bellow is an example of self-descriptive message. It contains information about protocol, host, which type of action need to be performed (HTTP method), and desired resource representation to be returned (Accept header). Such a message will be well understood by the server.

http
GET /employees/123 HTTP/1.1
Host: example.org
Accept: application/json

http
HTTP/1.1 200 OK
Content-Type: application/json
{
  "employeeId": 123,
  "firstName": "John",
  "lastName": "Doe"
}

Hypermedia as the engine of application state (HATEOAS)

Together, the first three uniform interface constraints imply the fourth. It can be summarise as that: sending self-desciptive messages to uniquely identifying resources, using representations, changes the state of the application. This constraint allows to compare the RESTful API to a website. As a website is a collection of links leading to subsequent subpages, HATEOAS informs that the same can be done with API. Also think of it as an situation in the office when you want to start a new business. You can't just go there and "POST" a new company. You must submit an application for creating a new company and then you will receive anwser like "Thank you for submitting an aplication. Here are the next possible steps that you can perform: cancellation of the application, address change, financing".

http
POST http://example.org/companies
{
  "name": "NewOne",
  "address": "Example 5",
  "owner": {
    "firstName": "John",
    "lastName": "Doe"
  }
}

http
HTTP/1.1 201 Created
{
  "companyId": 1234,
  "name": "NewOne",
  "address": "Example 5",
  "owner": {
    "firstName": "John",
    "lastName": "Doe"
  },
  "_links":{
    "self":{
      "href": "http://example.org/companies/1234",
      "method": "GET"
    },
    "cancellation":{
      "href": "http://example.org/companies/1234",
      "method": "DELETE"
    }
  }
}

API Versioning

Filters

Middleware

Inversion of Control and Dependency Injection

API Testing

Projects structure

Logging

General

Log Levels

By default in .NET Core there are six levels of logging (available through LogLevel enum): -

Trace

0

Debug

1

Information

2

Warning

3

Error

4

Critical

5

None

6

It's important to keep in mind that

Trace

Debug

Trace

Log Categories

Each logger instance needs to have an assigned category. Categories allow to group logs messages (as a category will be added to each log entry). By convention category should be passed as the type parameter of ILogger. Usually it's the class that we're injecting logger, eg.

[Route("api/Reservations")]
public class ReservationsController: Controller
{
    private readonly ILogger logger;

public ReservationsController(ILogger<reservationscontroller> logger)
{
    this.logger = logger;
}

[HttpPost]
public async Task<iactionresult> Create([FromBody] CreateReservationRequest request)
{
    var reservationId = Guid.NewGuid();

    // (...) 

    logger.LogInformation("Created reservation with {ReservationId}", reservationId);


    return Created("api/Reservations", reservationId);
}
}

Log category created with type parameter will contain full type name (so eg.

LoggingSamples.Controllers.ReservationController

It's also possible (however not recommended) to define that through ILoggerFactory

CreateLogger(string categoryName)

[Route("api/Reservations")]
public class ReservationsController: Controller
{
    private readonly ILogger logger;

public ReservationsController(ILoggerFactory loggerFactory)
{
    this.logger = logger.CreateLogger("LoggingSamples.Controllers.ReservationController");
}
}

Categories are useful for searching through logs and diagnose issues. As mentioned in the previous section - it's also possible to define in different log levels for configuration.

Eg. if you have a default log level

Information

ReservationsController

Debug

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "LoggingSamples.Controllers.ReservationController": "Debug"
    }
  }
}

Then for all categories but

LoggingSamples.Controllers.ReservationController

Information

Warning

Error

Critical

LoggingSamples.Controllers.ReservationController

Debug

The other example is to disable logs from selected category - eg. - because you noticed that is logging some sensitive information and you need quickly to change that, - you want to mute some unimportant system logs, - you want to make sure that logs from a specific category (eg.

LoggingSamples.Controllers.AuthenticationController

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "LoggingSamples.Controllers.AuthenticationController": "None"
    }
  }
}

Log Scopes

Besides categories, it's possible to define logging scopes. They allow having add set of custom information to each log entry.

Scopes are disabled by default - if you'd like to use them then you need to toggle them on in configuration:

{
  "Logging": {
    "IncludeScopes": true,
    "LogLevel": {
      "Default": "Information"
    }
  }
}

Having that you can use ILogger.BeginScope method to define one or more logging scopes.

The first potential use case is to always add entity type and identifier to all logs in business logic to not need to add it in each entry. Eg. reservation id during its update. You can also create nested scopes.

[HttpPut]
public async Task Create(Guid id, [FromBody] UpdateReservationRequest request)
{
    using(logger.BeginScope("For {EntityType}", "Reservation")
    {
         using(logger.BeginScope("With {EntityId}", id)
         {    
              logger.LogInformation("Starting reservation update process for {request}", request);
              // (...)
         }
    }

return OK();
}

You can create also scopes with aspect programming way - so eg. in middleware to inject scopes globally.

An example would be injecting as logging scope information from request eg. client IP, user id.

Sample below shows how to inject CorellationID into logger scope.

public class CorrelationIdMiddleware
{
    private readonly RequestDelegate next;
    private readonly ILogger logger;

public CorrelationIdMiddleware(RequestDelegate next, ILoggerFactory loggerFactory)
{
    this.next = next;
    logger = loggerFactory.CreateLogger<correlationidmiddleware>();
}

public async Task Invoke(HttpContext context /* other scoped dependencies */)
{
    var correlationID = Guid.NewGuid();

    using (logger.BeginScope($"CorrelationID: {CorrelationID}", correlationID))
    {
        await next(context);
    }
}
}

Log Events

The other option for grouping logs is log events. They are used normally to group them eg. by purpose - eg. updating an entity, starting controller action, not finding entity etc. To define them you need to provide a standardized list of int event ids. Eg.

public class LogEvents
{
    public const int InvalidRequest = 911;
    public const int ConflictState = 112;
    public const int EntityNotFound = 1000;
}

Sample usage:

[HttpPut]
public IActionResult Update([FromBody] UpdateReservation request)
{
    logger.LogInformation("Initiating reservation creation for {seatId}", request?.SeatId);

if (request?.SeatId == null || request?.SeatId == Guid.Empty)
{
    logger.LogWarning(LogEvents.InvalidRequest, "Invalid {SeatId}", request?.SeatId);

    return BadRequest("Invalid SeatId");
}

if (request?.ReservationId == null || request?.ReservationId == Guid.Empty)
{
    logger.LogWarning(LogEvents.InvalidRequest, "Invalid {ReservationId}", request?.ReservationId);

    return BadRequest("Invalid ReservationId");
}

// (...)
return Created("api/Reservations", reservation.Id);
}

Links

• Microsoft Docs - Logging in ASP.NET Core
• Microsoft Docs - High-performance logging with LoggerMessage in ASP.NET Core
• Steve Gordon - High-Performance Logging in .NET Core
• Software Engineering StackExchange - Benefits of Structured Logging vs basic logging
• Message Templates
• Andre Newman - Tools and Techniques for Logging Microservices
• Siva Prasad Rao Janapati - Distributed Logging Architecture for Microservices
• Szymon Warda - Stop trying to mock the ILogger methods
• Andrew Lock - How to include scopes when logging exceptions in ASP.NET Core
• Rico Suter - Logging with ILogger in .NET: Recommendations and best practices
• Stephen Cleary - Microsoft.Extensions.Logging
• Stephen Cleary - A New Pattern for Exception Logging

Serilog

Links

• Serilog Documentation
• Nicholas Blumhardt - Setting up Serilog in ASP.NET Core 3
• Ben Foster - Serilog Best Practices
• Alfus Jaganathan - Scoped logging using Microsoft Logger with Serilog in .Net Core Application

NLog

Links

• NLog Documentation
• NLog Wiki - How to use structured logging

Elastic Stack - Kibana, LogStash etc.

Links

• HumanKode - Logging with ElasticSearch, Kibana, ASP.NET Core and Docker
• Than Le - Building logging system in Microservice Architecture with ELK stack and Serilog .NET Core
• Marco de Sanctis - Monitor ASP.NET Core in ELK through Docker and Azure Event Hubs
• Microsoft Docs - Logging with Elastic Stack
• Ali Mselmi - Structured logging with Serilog and Seq and ElasticSearch under Docker
• Logz.io - Complete Guide to ELK Stack
• Logz.io - Best practices for managing ElasticSearch indices
• Andrew Lock - Writing logs to Elasticsearch with Fluentd using Serilog in ASP.NET Core
• Elastic Documentation - Install ElasticSearch with Docker
• AWS User Group Bengaluru - Log analytics with ELK stack

CorrelationId

Links

• Steve Gordon - ASP.NET Core Correlation IDs
• Steve Gordon - CorrelationId NuGet Package
• Vicenç García - Capturing and forwarding correlation IDs in ASP.NET Core
• Vicenç García - Capturing and forwarding correlation IDs in ASP.NET Core, the easy way

Docker

To setup docker configuration you need to create Dockerfile (usually it's located in the root project folder).

Docker allows to define complete build and runtime setup. It allows also multistage build. Having that, you can use in first stage different tools for building the binaries. Then in the next stage you can just copy the prepared binaries and host them in the final image. Thank to that the final docker image is smaller and more secure as it doesn't contain eg. source codes and build tools.

Microsoft provides docker images that can be used as a base for the Docker configuration. You can choose from various, but usually you're using either: -

mcr.microsoft.com/dotnet/core/sdk:3.1

mcr.microsoft.com/dotnet/core/sdk:3.1-alpine

It's recommended to start with

alpine

Sample DOCKERFILE

See example of

DOCKERFILE

########################################
#  First stage of multistage build
########################################
#  Use Build image with label `builder
########################################
FROM mcr.microsoft.com/dotnet/core/sdk:3.1-alpine AS builder

Setup working directory for project
WORKDIR /app
Copy project files
COPY *.csproj ./
Restore nuget packages
RUN dotnet restore
Copy project files
COPY . ./
Build project with Release configuration
and no restore, as we did it already
RUN dotnet build -c Release --no-restore
Test project with Release configuration
and no build, as we did it already
#RUN dotnet test -c Release --no-build
Publish project to output folder
and no build, as we did it already
RUN dotnet publish -c Release --no-build -o out
########################################
Second stage of multistage build
########################################
Use other build image as the final one
that won't have source codes
########################################
FROM mcr.microsoft.com/dotnet/core/runtime:3.1-alpine
Setup working directory for project
WORKDIR /app
Copy published in previous stage binaries
from the builder image
COPY --from=builder /app/out .
Set URL that App will be exposed
ENV ASPNETCORE_URLS="http://*:5000"
sets entry point command to automatically
run application on docker run
ENTRYPOINT ["dotnet", "DockerContainerRegistry.dll"]

Debugging application inside Docker

All modern IDE allows to debug ASP.NET Core application that are run inside the local docker. See links:

• Rider - Debugging ASP.NET Core apps in a local Docker container
• Visual Studio Code - ASP.NET Core in a container
• Niranjan Singh - How to enable docker support ASP.NET applications in Visual Studio

Links

• Download Docker
• Docker Hub
• Microsoft Docker images
• Vladislav Supalov - Docker ARG, ENV and .env - a Complete Guide

Storage

EntityFramework

Dapper

Azure

App Services

Links

• Microsoft Documentation - Azure CLI - Containers

Azure ARM Templates

Links

• Microsoft Documentation - ARM Templates
• Microsoft Github - Learning ARM
• Microsoft Documentation - Azure CLI - ARM Deployments
• Microsoft Documentation - Tutorial: Build a custom image and run in App Service from a private registry
• Microsoft Documentation - What if deployment
• Microsoft Documentation - ARM Templates Reference

Azure Key Vault

Links

• Microsoft Documentation - Quickstart: Set and retrieve a secret from Azure Key Vault using Azure CLI
• Microsoft Documentation - Use Azure Key Vault to pass secure parameter value during deployment

AWS

CI/CD

Azure DevOps Pipelines

Setting up Docker Resources

Azure Devops has built in

[email protected]

To use it, it's needed to configure Azure Resource Manager comnnection. It's possible to do either with default service principal or by setting up custom one with set of permissions.

To allow new resource group creation you need to add at least

Microsoft.Resources/subscriptions/resourcegroups/write

Access Control (IAM)

Contributor

Sample usage would be, creating new resource group and Azure Container Registry:

parameters:
  vmImageName: 'ubuntu-16.04'
  resourceGroupName: ''
  imageRepository: ''
  subscription: ''

stages:

stage: create_azure_group_and_azure_docker_registry
displayName: Create Azure Group And Azure Docker Registry
jobs:

job: create_azure_group_and_azure_docker_registry
pool:
  vmImageName: ${{ parameters.vmImageName }}
steps:

task: [email protected]
displayName: Create Resource Group
inputs:
  azureSubscription: ${{ parameters.subscription }}
  scriptLocation: 'inlineScript'
  inlineScript: az group create --name ${{ parameters.resourceGroupName }} --location northeurope

task: [email protected]
displayName: Create Azure Container Registry
inputs:
  azureSubscription: ${{ parameters.subscription }}
  scriptLocation: 'inlineScript'
  inlineScript: az acr create --resource-group ${{ parameters.resourceGroupName }} --name ${{ parameters.imageRepository }} --sku Basic

Sample usage of this template would look like:

variables:
vmImageName: 'ubuntu-16.04'
imageRepository: dockercontainerregistrysample
dockerRegistryServiceConnection: AzureDockerRegistry
resourceGroupName: WebApiWithNetCore
subscription: AzureWebApiWithNetCore







stages:

template: AzureDevOps/Stages/CreateAzureGroupAndAzureDockerRegistry.yml
parameters:
  imageRepository: $(imageRepository)
  resourceGroupName: $(resourceGroupName)
  subscription: $(subscription)
  vmImageName: $(vmImageName)

Links:

Building and pushing image to Docker Registry

Template for building and pushing Docker image

Setup the universal template as follows (with eg. filename

BuildAndPublishDocker.yml

parameters:


name: imageRepository

name: dockerRegistryServiceConnection

name: tag
type: string

name: vmImageName
default: 'ubuntu-16.04'

name: dockerfilePath
default: DOCKERFILE


######################################################
Stage definition
######################################################
stages:

stage: build_and_push_docker_image
displayName: Build and push Docker image
jobs:

job: Build
displayName: Build job
pool:
  vmImage: ${{ parameters.vmImageName }}
steps:

checkout: self

task: [email protected]
displayName: Build a Docker image
inputs:
  command: build
  repository: ${{ parameters.imageRepository }}
  dockerfile: ${{ parameters.dockerfilePath }}
  containerRegistry: ${{ parameters.dockerRegistryServiceConnection }}
  tags: |
${{ parameters.tag }}

task: [email protected]
displayName: Push a Docker image to container registry
condition: and(succeeded(), eq(variables['Build.SourceBranch'], 'refs/heads/main'))
inputs:
  command: push
  repository: ${{ parameters.imageRepository }}
  dockerfile: ${{ parameters.dockerfilePath }}
  containerRegistry: ${{ parameters.dockerRegistryServiceConnection }}
  tags: |
${{ parameters.tag }}

Azure Docker Registry

Before running the pipeline, you need to manually using

Azure Cloud Shell

`az group create --name WebApiWithNETCore --location westus`

1. Create Azure Container Registry, eg.

   az acr create --resource-group WebApiWithNETCore --name dockercontainerregistrysample --sku Basic

2. Setup service connection in Azure Devops. See more in documentation

Use defined stage template and define needed variables, eg.:

variables:
  # image version (tag) variables
  major: 1
  minor: 0
  patch: 0
  build: $[counter(variables['minor'], 0)] #this will reset when we bump patch
  tag: $(major).$(minor).$(patch).$(build)
  vmImageName: 'ubuntu-16.04'
  dockerfilePath: CD/DockerContainerRegistry/DOCKERFILE
  imageRepository: dockercontainerregistrysample
  dockerRegistryServiceConnection: AzureDockerRegistry

stages:

template: AzureDevOps/Stages/BuildAndPublishDocker.yml
parameters:
  imageRepository: imageRepository
  dockerRegistryServiceConnection: dockerRegistryServiceConnection
  tag: tag
  vmImageName: vmImageName
  dockerfilePath: dockerfilePath

See more in the pipeline definition: link.

Links: - Microsoft Documentation - Azure Container Registry Authentication

Docker Hub

Before running the pipeline, you need to manually using

Azure Cloud Shell

Use defined stage template and define needed variables, eg.:

variables:
  # image version (tag) variables
  major: 1
  minor: 0
  patch: 0
  build: $[counter(variables['minor'], 0)] #this will reset when we bump patch
  tag: $(major).$(minor).$(patch).$(build)
  vmImageName: 'ubuntu-16.04'
  dockerfilePath: CD/DockerContainerRegistry/DOCKERFILE
  imageRepository: oskardudycz/dockercontainerregistrysample
  dockerRegistryServiceConnection: DockerHubDockerRegistry

stages:

template: AzureDevOps/Stages/BuildAndPublishDocker.yml
parameters:
  imageRepository: imageRepository
  dockerRegistryServiceConnection: dockerRegistryServiceConnection
  tag: tag
  vmImageName: vmImageName
  dockerfilePath: dockerfilePath

Publishing application to App Services

Links

• Microsof Documentation - Quickstart: Use an Azure Resource Manager template to deploy a Linux web app to Azure
• Microsoft Documentation - Azure Resource Group Deployment Task

Links

• AzureDevOps documentation - Service connections
• StackOverflow - Entity Framework Migrations in Azure Pipelines
• Azure DevOps Labs - Deploying a Docker based web application to Azure App Service
• Chris Sainty - Deploying Containerised Apps to Azure Web App for Containers
• Microsoft Documentation - Run a custom Windows container in Azure
• Barbara 4bes - Step by step: Setup a CICD pipeline in Azure DevOps for ARM templates

Github Actions

• Barbara 4bes - Step by step: Test and deploy ARM Templates with GitHub Actions

Building and pushing image to Docker Registry

Docker Hub

Before running the pipeline: 1. Create an account and sign in to Docker Hub. 2. Go to Account Settings => Security: link and click New Access Token. 3. Provide the name of your access token, save it and copy the value (you won't be able to see it again, you'll need to regenerate it). 4. Go to your GitHub secrets settings (Settings => Secrets, url

https://github.com/{your_username}/{your_repository_name}/settings/secrets/actions

DOCKERHUB_USERNAME

DOCKERHUB_TOKEN

Then add new file in the

.github/workflows

name: Build And Publish Docker To DockerHub

on: [push]
jobs:
  build:
    runs-on: ubuntu-latest
steps:
  - name: Check Out Repo
    uses: actions/[email protected]

  - name: Login to DockerHub
    uses: docker/[email protected]
    with:
      # Use secrets defined in GithubRepository
      # Based on the generated in DockerHub token
      username: ${{ secrets.DOCKERHUB_USERNAME }}
      password: ${{ secrets.DOCKERHUB_TOKEN }}

  - name: Set up Docker Buildx
    id: buildx
    uses: docker/[email protected]

  - name: Build and push
    id: docker_build
    uses: docker/[email protected]
    with:
      # build image in pull requests
      # publish only if branch is `main`
      push: ${{ github.ref == 'refs/heads/main'}}
      # define at which tag should be docker image published
      tags: oskardudycz/webapi_net_core_github_actions:latest
      # path to your project subfolder
      context: ./CD/DockerContainerRegistry
      # path to Dockerfile
      file: ./CD/DockerContainerRegistry/DOCKERFILE

  - name: Image digest
    run: echo ${{ steps.docker_build.outputs.digest }}

Links

• Docker - Configure GitHub Actions
• Docker Blog - Ben De St Paer-Gotch - Docker Github Actions
• GitHub - Publishing Docker images
• GitHub Actions MarketPlace - Build and push Docker images

Caching

GraphQL

Links

• Michael Staib - HotChocolate: An Introduction to GraphQL for ASP.NET Core
• Michael Staib - Get started with GraphQL and Entity Framework

CQRS

OAuth

Links

• Microsoft Documentation - Security and Identity
• Identity Server documentation
• Auth0 - SSO for Regular Web Apps: ASP.NET Core Implementation