title: Azure Function Docker image and the dependencies being restored
body: <p>We're building Azure Durable Function that uses Python as the main language. The Docker image we found in GitHub and use now takes .NET Core SDK 3.1 as a base image and restores the 'WebJobs.Script.WebHost' project. The question is, why do we need .NET SDK/Runtime here if the Function is Python-based:</p>
  <pre><code>FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS runtime-image
  ARG HOST_VERSION
  
  ENV PublishWithAspNetCoreTargetManifest=false
  
  RUN BUILD_NUMBER=$(echo ${HOST_VERSION} | cut -d'.' -f 3) &amp;&amp; \
      git clone --branch v${HOST_VERSION} https://github.com/Azure/azure-functions-host /src/azure-functions-host &amp;&amp; \
      cd /src/azure-functions-host &amp;&amp; \
      HOST_COMMIT=$(git rev-list -1 HEAD) &amp;&amp; \
      dotnet publish -v q /p:BuildNumber=$BUILD_NUMBER /p:CommitHash=$HOST_COMMIT src/WebJobs.Script.WebHost/WebJobs.Script.WebHost.csproj -c Release --output /azure-functions-host --runtime linux-x64 &amp;&amp; \
      mv /azure-functions-host/workers /workers &amp;&amp; mkdir /azure-functions-host/workers &amp;&amp; \
      rm -rf /root/.local /root/.nuget /src
  </code></pre>
  <p><a href="https://github.com/Azure/azure-functions-docker/blob/master/host/3.0/buster/amd64/python/python37/python37.Dockerfile" rel="nofollow noreferrer">Link to a GitHub project that contains Docker images for Python</a>.
  The Docker manifest also takes Python later in the manifest and restores its dependencies as it should be. However, it seems like an enormous overhead which results in a container of almost 2Gb in size.</p>
  <p>At the same time, whenever I create a project via the CLI (with the Docker image included) it generates a manifest like this:</p>
  <pre><code>FROM mcr.microsoft.com/azure-functions/python:3.0-python3.7
  
  ENV AzureWebJobsScriptRoot=/home/site/wwwroot \
      AzureFunctionsJobHost__Logging__Console__IsEnabled=true
  
  COPY requirements.txt /
  RUN pip install -r /requirements.txt
  
  COPY . /home/site/wwwroot
  </code></pre>
  <p>Yes, Azure Durable Functions for Python is in preview now. But is this a reason for the huge Docker manifest file with .NET Core and restoring  'WebJobs.Script.WebHost'? What's the fundamental diff between these manifests? Or my understanding is entirely wrong?</p>