Azure pipeline not applying label to Docker build container - azure

Question

As the title says, I am trying to apply a label to my docker container so I can then reference said container in a further step in my pipeline. My end result that I am going for is to be able to copy my test results out of the container and publish and display those results.
azure-pipeline.yml
# Docker
# Build a Docker image
# https://learn.microsoft.com/azure/devops/pipelines/languages/docker
trigger:
- main
- develop
resources:
- repo: self
variables:
tag: '$(Build.BuildId)'
stages:
- stage: Build
displayName: Build image
jobs:
- job: Build
displayName: Build
pool:
name: default
steps:
- task: Docker#2
displayName: Build an image
inputs:
command: build
arguments: '--build-arg BuildId=$(Build.BuildId)'
dockerfile: '$(Build.SourcesDirectory)/Dockerfile'
tags: |
$(tag)
- powershell: |
$id=docker images --filter "label=test=$(Build.BuildId)" -q | Select-Object -First 1
docker create --name testcontainer $id
docker cp testcontainer:/testresults ./testresults
docker rm testcontainer
displayName: 'Copy test results'
- task: PublishTestResults#2
displayName: 'Publish test results'
inputs:
testResultsFormat: 'xUnit'
testResultsFiles: '**/*.trx'
searchFolder: '$(System.DefaultWorkingDirectory)/testresults'
Dockerfile
#See https://aka.ms/containerfastmode to understand how Visual Studio uses this Dockerfile to build your images for faster debugging.
FROM mcr.microsoft.com/dotnet/aspnet:6.0-bullseye-slim-amd64 AS base
WORKDIR /app
EXPOSE 80
FROM mcr.microsoft.com/dotnet/sdk:6.0-bullseye-slim-amd64 AS build
WORKDIR /src
COPY ["Forecast/Forecast.csproj", "Forecast/"]
WORKDIR "/src/Forecast"
RUN dotnet restore "Forecast.csproj"
COPY Forecast/ .
RUN dotnet build "Forecast.csproj" -c Release -o /app/build
FROM build AS publish
WORKDIR /src
RUN dotnet publish "Forecast/Forecast.csproj" --no-restore -c Release -o /app/publish
FROM build as test
ARG BuildId
LABEL test=${BuildId}
WORKDIR /src
COPY ["ForecastXUnitTest/ForecastXUnitTest.csproj", "ForecastXUnitTest/"]
WORKDIR "/src/ForecastXUnitTest"
RUN dotnet restore "ForecastXUnitTest.csproj"
COPY ForecastXUnitTest/ .
RUN dotnet build "ForecastXUnitTest.csproj" -c Release -o /app
RUN dotnet test -c Release --results-directory /testresults --logger "trx;LogFileName=test_results.trx" "ForecastXUnitTest.csproj"
FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "Forecast.dll"]
I can see that the label hasn't been applied upon inspection of the build steps. The powershell step specifically the line docker create --name testcontainer $id the variable $id is empty and is telling me that the label is never applied so I'm not able to go any further.

Answer 1

I ended up figuring out where my issue lay. I end up with cache'd ephemeral container images. With these in place Docker no longer runs those steps so along the way I added in the steps but with what had preceded in builds I wasn't getting anything from subsequent calls.
On top of this I had been referring to a previous image with the directive FROM that was preventing my directory from being found.