Thursday, April 30, 2020

Visual C# Technical Guru - March 2020

Another month as a judge in Microsoft TechNet Guru Awards under Visual C# category. The TechNet Guru Awards celebrate the technical articles on Microsoft TechNet.

Post in Official Blog,
https://techcommunity.microsoft.com/t5/wiki-ninjas-blog/technet-wiki-guru-winners-march-2020/ba-p/1349990
Visual C# Technical Guru - March 2020
Happy Coding.

Regards,
Jaliya

Sunday, April 5, 2020

Basic Azure DevOps Pipeline to deploy an ASP.NET Core Containerized Application and Applying EF Core Database Migrations

In this post, I am going to share a sample azure-pipelines.yml to deploy an ASP.NET Core Containerized Application and Applying Entity Framework Core Database Migrations.

Here the pipeline is based on the following requirement which I believe is common.
  1. When doing the release, we need to apply database migrations in the target database. The migration script will be created on the fly during the execution of the pipeline and will be executed on the target database.
  2. We might need to execute some additional SQL scripts in the target database after the database is migrated, maybe to CREATE/ALTER stored procedures, etc. The pipeline assumes those scripts are residing in scripts/postdeploy folder in the root of the project.
I have left comments in the below azure-pipelines.yml itself, so I don't think any other explanation is necessary. You should be able to changes this as per your needs.

azure-pipelines.yml
trigger:
- master

resources:
repo: self

variables:
  # Container registry service connection established during pipeline creation  
  dockerRegistryServiceConnection: '<dockerRegistryServiceConnection>'

  # Something like xxxxxx.azurecr.io
  containerRegistry: '<containerRegistry>'

  # Docker image name
  imageRepository: '<imageRepository>'

  # The relative localtion of the Dockerfile
  dockerfilePath: '$(Build.SourcesDirectory)/Dockerfile'

  # This docker image will be tagged using this
  tag: '$(Build.BuildId)'

  # Agent to be used
  vmImageName: 'ubuntu-latest'

# We have 2 stages, 
#   1. Build
#   2. Release
stages:

# This stage will and build the docker image and push it to ACR
stage: Build
  displayName: Build and push stage
  jobs:
    - job: Build
      displayName: Build
      pool:
        vmImage: $(vmImageName)
      steps:

      - task: Docker@2
        displayName: Build and push an image to container registry
        inputs:
          command: buildAndPush
          repository: $(imageRepository)
          dockerfile: $(dockerfilePath)
          containerRegistry: $(dockerRegistryServiceConnection)
          tags: |
            $(tag)

# This stage will,
#   1. Create a database migration script named update-database.sql inside scripts folder
#   2. Execute the migration script first
#   3. Then execute all the other SQL scripts inside scripts/postdeploy folder
#   4. Finally spin up the container at the target web app
stage: Release  
  displayName: Release stage
  jobs:
    - job: Release
      displayName: Release
      pool:
        vmImage: $(vmImageName)
      steps:

      # This task is required to run dotnet-ef which is getting installed in the next task
      - task: UseDotNet@2
        inputs:
          version: '3.1.200'

      # Install dotnet-ef
      - task: DotNetCoreCLI@2
        displayName: Install dotnet-ef
        inputs:
          command: 'custom'
          custom: 'tool'
          arguments: 'install --global dotnet-ef --ignore-failed-sources'

      # Generate update-database.sql using dotnet-ef
      - task: PowerShell@2
        displayName: Generate Database Migration Script
        inputs:
          targetType: 'inline'
          script: |
            # Splitted into multiple lines for brevity. Below command needs to be a single line
            dotnet ef migrations script 
              -i 
              -o "$(Build.SourcesDirectory)/scripts/update-database.sql" 
              --project "$(Build.SourcesDirectory)/<ProjectThatContainsTheDbContext.csproj>" 
              --startup-project "$(Build.SourcesDirectory)/<TheStartupProject.csproj>"

    # Install SqlServer module to be able to run Invoke-SqlCmd in the next task
      - task: PowerShell@2
        displayName: PowerShell Install-Module SqlServer
        inputs:
          targetType: 'inline'
          script: 'Install-Module -Name SqlServer -AllowPrerelease -Force -Verbose -Scope CurrentUser'

    # Execute the update-database.sql in the target database
      - task: PowerShell@2
        displayName: PowerShell Invoke-Sqlcmd Database Migration Script
        inputs:
          targetType: 'inline'
          script: |
            # Splitted into multiple lines for brevity. Below command needs to be a single line
            Invoke-Sqlcmd 
              -ServerInstance "<ServerInstance>" 
              -Database "<Database>" 
              -Username "<Username>" 
              -Password "<Password>" 
              -Inputfile "$(Build.SourcesDirectory)/scripts/update-database.sql" 
              -Verbose 
              -ConnectionTimeout 120

      # Execute other SQL scripts in the target database
      - task: PowerShell@2
        displayName: PowerShell Invoke-Sqlcmd Other SQL Scripts
        inputs:
          targetType: 'inline'
          script: |
            $files = Get-ChildItem $(Build.SourcesDirectory)/scripts/postdeploy
            foreach ($f in $files) 
            {
              # Splitted into multiple lines for brevity. Below command needs to be a single line
              Invoke-Sqlcmd 
                -ServerInstance "<ServerInstance>" 
                -Database "<Database>" 
                -Username "<Username>" 
                -Password "<Password>" 
                -Inputfile "$f" 
                -Verbose 
                -ConnectionTimeout 120
            }

      # All good, let's spin up a new container at the target web app
      - task: AzureWebAppContainer@1
        displayName: Spin up the container
        inputs:
          azureSubscription: '<azureSubscription>'
          appName: '<appName>'
          containers: $(containerRegistry)/$(imageRepository):$(tag)

          # Something like dotnet TheStartupProject.dll
          containerCommand: '<containerCommand>'
Hope this helps.

Happy Coding.

Regards,
Jaliya

Friday, April 3, 2020

Invoke Invoke-SqlCmd inside a Linux Agent in Azure DevOps Pipelines

I was trying to execute Invoke-Sqlcmd command inside a Linux Agent in Azure DevOps Pipelines and getting this error.

"The term 'Invoke-Sqlcmd' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again."
The term 'Invoke-Sqlcmd' is not recognized...
Then according to this post: Invoke-Sqlcmd is Now Available Supporting Cross-Platform, installed SqlServer module from another PowerShell@2 task.
- task: PowerShell@2
  inputs:
    targetType: 'inline'
    script: 'Install-Module -Name SqlServer -AllowPrerelease'
That task passed, but still, the PS Invoke-SqlCmd task was throwing the same error. But noticed this warning inside PS Install-Module task.

"WARNING: User declined to install module (SqlServer)."
WARNING: User declined to install module (SqlServer)
Then I modified the PS Install-Module task to pass in an additional parameter -Scope CurrentUser.
- task: PowerShell@2
  inputs:
    targetType: 'inline'
    script: 'Install-Module -Name SqlServer -AllowPrerelease -Force -Verbose -Scope CurrentUser'
This time it got installed successfully.
Install-Module -Name SqlServer
And finally I was able to run Invoke-SqlCmd inside a Linux Agent in Azure DevOps Pipeline.
Invoke-SqlCmd is running
Hope this helps!

Happy Coding.

Regards,
Jaliya

Thursday, April 2, 2020

dotnet ef is Failing in Azure DevOps Pipeline When the Agent is ubuntu-latest

I was trying to run dotnet ef command within Azure DevOps Pipeline and it's failing with the error: Could not execute because the specified command or file was not found. This is even after installing the dotnet ef tool.
trigger:
- master
 
resources:
- repo: self
 
variables:
  vmImageName: 'ubuntu-latest'
 
stages:
 
- stage: Build
  displayName: Build and push stage
  jobs:  
  - job: Build
    displayName: Build
    pool:
      vmImage: $(vmImageName)
    steps:
    - task: DotNetCoreCLI@2
      displayName: Install dotnet-ef
      inputs:
        command: 'custom'
        custom: 'tool'
        arguments: 'install --global dotnet-ef'
    - task: DotNetCoreCLI@2
      displayName: Check dotnet-ef version
      inputs:
        command: 'custom'
        custom: 'ef'
        arguments: '--version'
So here I have 2 tasks, in the first task is I am installing dotnet-ef and in the second task, I am just checking the version.

This is failing with the error: Could not execute because the specified command or file was not found.

The reason turned out to be, we need to use the UseDotnet@2 task first, to install the dotnet sdk and then install the dotnet ef. This will make dotnet-ef installed into same path as of dotnet sdk and will make it able to execute.
Use .NET Core
trigger:
- master
 
resources:
- repo: self
 
variables:
  vmImageName: 'ubuntu-latest'
 
stages:
 
- stage: Build
  displayName: Build
  jobs:  
  - job: Build
    displayName: Build
    pool:
      vmImage: $(vmImageName)
    steps:
    - task: UseDotNet@2
      inputs:
        version: '3.1.200'
    - task: DotNetCoreCLI@2
      displayName: Install dotnet-ef
      inputs:
        command: 'custom'
        custom: 'tool'
        arguments: 'install --global dotnet-ef'
    - task: DotNetCoreCLI@2
      displayName: Check dotnet-ef version
      inputs:
        command: 'custom'
        custom: 'ef'
        arguments: '--version'
So this works. Hope this helps!

Happy Coding.

Regards,
Jaliya

Wednesday, April 1, 2020

IdentityServer4: Adding Additional Claims to the Token

In this post let's see how we can additional claims to the token. This can be either creating tokens or when handling requests to the userinfo or introspection endpoints. In addition, let's have a look at how we can add in additional claims to a client ASP.NET Core application.

IS4, provides an interface IProfileService which we can implement to add in additional claims. It's basically going to be something like this.
public class ProfileService : IProfileService
{
    public ProfileService()
    {
    }
 
    public async Task GetProfileDataAsync(ProfileDataRequestContext context)
    {
        // Get all the claims you need to add into the token by context.Subject
        // Set it to context.IssuedClaims
        // This is expected to be populated
    }
 
    public async Task IsActiveAsync(IsActiveContext context)
    {
        // Check context.Subject is allowed to retrieve additional claims
        // Based on that set context.IsActive
        // This is expected to be set
    }
}
So here one of the important things is, context contains a property named Caller, as the name suggests that determines what triggered this call. Unfortunately, it's a type of string, but there is a set of constants in ID4, that you can use.
public static class ProfileDataCallers
{
    public const string UserInfoEndpoint = "UserInfoEndpoint";
    public const string ClaimsProviderIdentityToken = "ClaimsProviderIdentityToken";
    public const string ClaimsProviderAccessToken = "ClaimsProviderAccessToken";
}
So by checking the context.Caller, you can decide which claims you want to include based on the Caller.

Plugging in ProfileService to IdentityServer is quite simple, we can just do as follows when we are adding IdentityServer.
AddProfileService
It's pretty neat!

Sometimes, you might face a scenario, you want to add in additional claims, not when the token issued from ID4, but from the client ASP.NET Core application. Basically, this is how we protect an ASP.NET Core Web API application with an ID4.
services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
    .AddJwtBearer(options =>
    {
        // set Authority and additional options
    });
Instead of using AddJwtBearer, we can use AddIdentityServerAuthentication authentication handler which is available in IdentityServer4.AccessTokenValidation NuGet package.
services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
    .AddIdentityServerAuthentication(options =>
    {
        // set Authority and additional options

        options.JwtBearerEvents.OnTokenValidated = OnTokenValidated;
    });
There we can handle the OnTokenValidated event. This will be invoked after the security token has passed validation and a ClaimsIdentity has been generated. So here also we can additional claims. But there is a downside with this approach, each time the API is being called with the token, this will get invoked.
private async Task OnTokenValidated(TokenValidatedContext context)
{
    // var identity = context.Principal.Identity as ClaimsIdentity;
    // identity.AddClaim(new Claim("X","Y");
}
So hope this bit of information helps.

Happy Coding.

Regards,
Jaliya