Summary: Python hints, tips, oneliners and best practices.
Date: 8 December 2024

- task: PythonScript@0
  displayName: "Sort and print all system environments "
  inputs:
    scriptSource: 'inline'
    script: |
      import os
      for name, value in sorted(os.environ.items()):
        print("   " + name + "=" + value)

- task: PythonScript@0
  displayName: "Python version "
  inputs:
    scriptSource: 'inline'
    script: |
      import subprocess
      import os
      if os.environ['AGENT_OS'] == "Linux":
        version = subprocess.getoutput('python3 --version')
      elif os.environ['AGENT_OS'] == "Windows_NT":
        version = subprocess.getoutput('py -3 --version')
      else:
        version = "unknown"
      print(f"Python version is {version}")

- task: PythonScript@0
  displayName: "Pip version "
  inputs:
    scriptSource: 'inline'
    script: |
      import subprocess
      pip = subprocess.getoutput('pip --version')
      print(f"Pip version is {pip}")

- task: PowerShell@2
  displayName: "Python virtual environment"
  inputs:
    pwsh: true
    targetType: 'inline'
    script: |
      Write-Host "`n##[section]Start python script`n"
      # Create virtual environment "env" by running module venv (https://packaging.python.org/en/latest/guides/installing-using-pip-and-virtual-environments/)
      py -m venv env
      .\env\Scripts\activate.ps1 -Verbose
      Write-Host "`n##[section]Verify virtual environment`n"
      Get-Command python.exe
      Write-Host "`n##[section]Install packages`n"
      $scriptDir = "$(BUILD.SourcesDirectory)\$(BUILD.REPOSITORY.NAME)\src\$module"
      Write-Host "Locatie: $(Get-Location); Script dir: $scriptDir"
      if (Test-Path $scriptDir\requirements.txt){
          Write-Host "Directory: $scriptDir; Requirements file: Present"
          py -m pip install -r $scriptDir\requirements.txt
      }else {
          Write-Host "Directory: $scriptDir; Requirements file: Not present. Installing from code."
          # install a package
          py -m pip install requests
          # install a specific version
          py -m pip install pandas==1.5.2
      }
      Write-Host "`n##[section]Run python script`n"
      if (Test-Path $scriptDir\main.py){
          Write-Host "Script: $scriptDir\main.py; Status: Present"
          py $scriptDir\main.py
      }else{
          Throw "Script: not found in $scriptDir"
      }
 
      Write-Host "`n##[section]Install packages`n"
      # install a package
      py -m pip install requests
      # install a specific version
      py -m pip install pandas==1.5.2