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Install python silently on Windows container and add to PATH

A container is a standard unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another.

In this article we will examine how we can silently install python on a container running windows and add it to path. By doing so we can run python scripts inside our container and perform various tests, or even create webservices that will be hosted as containers inside a Cloud provider.

In order to host python inside a windows system I am using the below Dockerfile. A file named configuration.ps1 could exist inside your building directory and contain other instructions like modules installation. If you do not want this step you can remove the last two lines of the Dockerfile.

FROM mcr.microsoft.com/dotnet/framework/sdk:4.8-windowsservercore-ltsc2019
 RUN Invoke-WebRequest -UseBasicParsing https://www.python.org/ftp/python/3.10.7/python-3.10.7-amd64.exe -OutFile python.exe; `
    Start-Process python.exe -Wait -ArgumentList /PrependPath=1, /quiet; `
    Remove-Item -Force python.exe
COPY ./configuration.ps1 .
CMD .\configuration.ps1

When python is installed inside your container you will need to add it on PATH in order to use the verb python. This is done by appending the installation directory on windows PATH.

In order to do you will need to get an interactive session with your container.

docker exec -it container_name powershell

With the below command you can find where is the python installation located. You will need to change python version to the one that you installed. If you had installed the version 3.5 then you would need to change 3.10 to 3.5.

py -3.10 -c "import sys; print(sys.executable[:-10])"

The last step would be to set this location in the PATH. You can do that using the command below.

setx path "%path%;C:\Users\ContainerAdministrator\AppData\Local\Programs\Python\Python310\"

Then you can just press python and voilà.

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Push multiple docker container images using a loop – Azure DevOps

On a pipeline that I was creating I wanted to push multiple docker images on an Azure container registry based on a list. In order to do that I used the docker@2 task on a loop providing the images that I had to push as a parameter. Code is attached below.

trigger:
– none
pr: none
parameters:
– name: containerlist
type: object
default: ["core/image1","core/image2","core/image3","core/image4"]
– name: DockerPushID
type: string
pool:
name: demo-app
stages:
– stage: containers
displayName: Push containers to container registry $(registry)
jobs:
– job: pushcontainers
displayName: Push containers on testexample.azurecr.io
steps:
– checkout: none
– ${{ each container in parameters.containerlist }}:
– task: Docker@2
displayName: pushing image ${{container}}
inputs:
containerRegistry: 'registryconnection'
repository: '${{container}}'
command: 'push'
tags: |
current-${{parameters.DockerPushID}}
current-latest

This task will run steps based on the images you provide on the parameters list. An important note is that you need to have the image named accordingly in order to get a successful result. For example if you need to push on geralexgr.azurecr.io you will need to have your images named as below.

geralexgr.azurecr.io/image1:current-latest
geralexgr.azurecr.io/image2:current-latest

Else you may notice some failures indicating the below.

The push refers to repository [***/kati/image1] 
An image does not exist locally with the tag: ***/kati/image1

A successful run of the pipeline.

Additional information regarding loops and expressions on Azure DevOps pipelines:

https://docs.microsoft.com/en-us/azure/devops/pipelines/process/expressions?view=azure-devops#functions

Video tutorial on YouTube: