build docker image for dotnet core app and pushes to docker registry

azure-pipeline.yml

# Build Docker image for this app using Azure Pipelines

pool:
  name: 'dockerized-vsts-agents'

variables:
  buildConfiguration: 'Release'
  imageName: 'dotnetcore:$(Build.BuildId)'

steps:
- script: |
    dotnet build --configuration $(buildConfiguration)
    dotnet test dotnetcore-tests --configuration $(buildConfiguration) --logger trx
    dotnet publish --configuration $(buildConfiguration) --output out
    docker build -f Dockerfile -t $(dockerId)/$(imageName) .
    docker login -u $(dockerUser) -p $pswd $(dockerId)
    docker push $(dockerId)/$(imageName)
  env:
    pswd: $(dockerPassword)  

- task: PublishTestResults@2
  condition: succeededOrFailed()
  inputs:
    testRunner: VSTest
    testResultsFiles: '**/*.trx'