venv/bin/Activate.ps1

   1 <#
   2 .Synopsis
   3 Activate a Python virtual environment for the current PowerShell session.
   4
   5 .Description
   6 Pushes the python executable for a virtual environment to the front of the
   7 $Env:PATH environment variable and sets the prompt to signify that you are
   8 in a Python virtual environment. Makes use of the command line switches as
   9 well as the `pyvenv.cfg` file values present in the virtual environment.
  10
  11 .Parameter VenvDir
  12 Path to the directory that contains the virtual environment to activate. The
  13 default value for this is the parent of the directory that the Activate.ps1
  14 script is located within.
  15
  16 .Parameter Prompt
  17 The prompt prefix to display when this virtual environment is activated. By
  18 default, this prompt is the name of the virtual environment folder (VenvDir)
  19 surrounded by parentheses and followed by a single space (ie. '(.venv) ').
  20
  21 .Example
  22 Activate.ps1
  23 Activates the Python virtual environment that contains the Activate.ps1 script.
  24
  25 .Example
  26 Activate.ps1 -Verbose
  27 Activates the Python virtual environment that contains the Activate.ps1 script,
  28 and shows extra information about the activation as it executes.
  29
  30 .Example
  31 Activate.ps1 -VenvDir C:\Users\MyUser\Common\.venv
  32 Activates the Python virtual environment located in the specified location.
  33
  34 .Example
  35 Activate.ps1 -Prompt "MyPython"
  36 Activates the Python virtual environment that contains the Activate.ps1 script,
  37 and prefixes the current prompt with the specified string (surrounded in
  38 parentheses) while the virtual environment is active.
  39
  40 .Notes
  41 On Windows, it may be required to enable this Activate.ps1 script by setting the
  42 execution policy for the user. You can do this by issuing the following PowerShell
  43 command:
  44
  45 PS C:\> Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
  46
  47 For more information on Execution Policies:
  48 https://go.microsoft.com/fwlink/?LinkID=135170
  49
  50 #>
  51 Param(
  52     [Parameter(Mandatory = $false)]
  53     [String]
  54     $VenvDir,
  55     [Parameter(Mandatory = $false)]
  56     [String]
  57     $Prompt
  58 )
  59
  60 <# Function declarations --------------------------------------------------- #>
  61
  62 <#
  63 .Synopsis
  64 Remove all shell session elements added by the Activate script, including the
  65 addition of the virtual environment's Python executable from the beginning of
  66 the PATH variable.
  67
  68 .Parameter NonDestructive
  69 If present, do not remove this function from the global namespace for the
  70 session.
  71
  72 #>
  73 function global:deactivate ([switch]$NonDestructive) {
  74     # Revert to original values
  75
  76     # The prior prompt:
  77     if (Test-Path -Path Function:_OLD_VIRTUAL_PROMPT) {
  78         Copy-Item -Path Function:_OLD_VIRTUAL_PROMPT -Destination Function:prompt
  79         Remove-Item -Path Function:_OLD_VIRTUAL_PROMPT
  80     }
  81
  82     # The prior PYTHONHOME:
  83     if (Test-Path -Path Env:_OLD_VIRTUAL_PYTHONHOME) {
  84         Copy-Item -Path Env:_OLD_VIRTUAL_PYTHONHOME -Destination Env:PYTHONHOME
  85         Remove-Item -Path Env:_OLD_VIRTUAL_PYTHONHOME
  86     }
  87
  88     # The prior PATH:
  89     if (Test-Path -Path Env:_OLD_VIRTUAL_PATH) {
  90         Copy-Item -Path Env:_OLD_VIRTUAL_PATH -Destination Env:PATH
  91         Remove-Item -Path Env:_OLD_VIRTUAL_PATH
  92     }
  93
  94     # Just remove the VIRTUAL_ENV altogether:
  95     if (Test-Path -Path Env:VIRTUAL_ENV) {
  96         Remove-Item -Path env:VIRTUAL_ENV
  97     }
  98
  99     # Just remove VIRTUAL_ENV_PROMPT altogether.
 100     if (Test-Path -Path Env:VIRTUAL_ENV_PROMPT) {
 101         Remove-Item -Path env:VIRTUAL_ENV_PROMPT
 102     }
 103
 104     # Just remove the _PYTHON_VENV_PROMPT_PREFIX altogether:
 105     if (Get-Variable -Name "_PYTHON_VENV_PROMPT_PREFIX" -ErrorAction SilentlyContinue) {
 106         Remove-Variable -Name _PYTHON_VENV_PROMPT_PREFIX -Scope Global -Force
 107     }
 108
 109     # Leave deactivate function in the global namespace if requested:
 110     if (-not $NonDestructive) {
 111         Remove-Item -Path function:deactivate
 112     }
 113 }
 114
 115 <#
 116 .Description
 117 Get-PyVenvConfig parses the values from the pyvenv.cfg file located in the
 118 given folder, and returns them in a map.
 119
 120 For each line in the pyvenv.cfg file, if that line can be parsed into exactly
 121 two strings separated by `=` (with any amount of whitespace surrounding the =)
 122 then it is considered a `key = value` line. The left hand string is the key,
 123 the right hand is the value.
 124
 125 If the value starts with a `'` or a `"` then the first and last character is
 126 stripped from the value before being captured.
 127
 128 .Parameter ConfigDir
 129 Path to the directory that contains the `pyvenv.cfg` file.
 130 #>
 131 function Get-PyVenvConfig(
 132     [String]
 133     $ConfigDir
 134 ) {
 135     Write-Verbose "Given ConfigDir=$ConfigDir, obtain values in pyvenv.cfg"
 136
 137     # Ensure the file exists, and issue a warning if it doesn't (but still allow the function to continue).
 138     $pyvenvConfigPath = Join-Path -Resolve -Path $ConfigDir -ChildPath 'pyvenv.cfg' -ErrorAction Continue
 139
 140     # An empty map will be returned if no config file is found.
 141     $pyvenvConfig = @{ }
 142
 143     if ($pyvenvConfigPath) {
 144
 145         Write-Verbose "File exists, parse `key = value` lines"
 146         $pyvenvConfigContent = Get-Content -Path $pyvenvConfigPath
 147
 148         $pyvenvConfigContent | ForEach-Object {
 149             $keyval = $PSItem -split "\s*=\s*", 2
 150             if ($keyval[0] -and $keyval[1]) {
 151                 $val = $keyval[1]
 152
 153                 # Remove extraneous quotations around a string value.
 154                 if ("'""".Contains($val.Substring(0, 1))) {
 155                     $val = $val.Substring(1, $val.Length - 2)
 156                 }
 157
 158                 $pyvenvConfig[$keyval[0]] = $val
 159                 Write-Verbose "Adding Key: '$($keyval[0])'='$val'"
 160             }
 161         }
 162     }
 163     return $pyvenvConfig
 164 }
 165
 166
 167 <# Begin Activate script --------------------------------------------------- #>
 168
 169 # Determine the containing directory of this script
 170 $VenvExecPath = Split-Path -Parent $MyInvocation.MyCommand.Definition
 171 $VenvExecDir = Get-Item -Path $VenvExecPath
 172
 173 Write-Verbose "Activation script is located in path: '$VenvExecPath'"
 174 Write-Verbose "VenvExecDir Fullname: '$($VenvExecDir.FullName)"
 175 Write-Verbose "VenvExecDir Name: '$($VenvExecDir.Name)"
 176
 177 # Set values required in priority: CmdLine, ConfigFile, Default
 178 # First, get the location of the virtual environment, it might not be
 179 # VenvExecDir if specified on the command line.
 180 if ($VenvDir) {
 181     Write-Verbose "VenvDir given as parameter, using '$VenvDir' to determine values"
 182 }
 183 else {
 184     Write-Verbose "VenvDir not given as a parameter, using parent directory name as VenvDir."
 185     $VenvDir = $VenvExecDir.Parent.FullName.TrimEnd("\\/")
 186     Write-Verbose "VenvDir=$VenvDir"
 187 }
 188
 189 # Next, read the `pyvenv.cfg` file to determine any required value such
 190 # as `prompt`.
 191 $pyvenvCfg = Get-PyVenvConfig -ConfigDir $VenvDir
 192
 193 # Next, set the prompt from the command line, or the config file, or
 194 # just use the name of the virtual environment folder.
 195 if ($Prompt) {
 196     Write-Verbose "Prompt specified as argument, using '$Prompt'"
 197 }
 198 else {
 199     Write-Verbose "Prompt not specified as argument to script, checking pyvenv.cfg value"
 200     if ($pyvenvCfg -and $pyvenvCfg['prompt']) {
 201         Write-Verbose "  Setting based on value in pyvenv.cfg='$($pyvenvCfg['prompt'])'"
 202         $Prompt = $pyvenvCfg['prompt'];
 203     }
 204     else {
 205         Write-Verbose "  Setting prompt based on parent's directory's name. (Is the directory name passed to venv module when creating the virtual environment)"
 206         Write-Verbose "  Got leaf-name of $VenvDir='$(Split-Path -Path $venvDir -Leaf)'"
 207         $Prompt = Split-Path -Path $venvDir -Leaf
 208     }
 209 }
 210
 211 Write-Verbose "Prompt = '$Prompt'"
 212 Write-Verbose "VenvDir='$VenvDir'"
 213
 214 # Deactivate any currently active virtual environment, but leave the
 215 # deactivate function in place.
 216 deactivate -nondestructive
 217
 218 # Now set the environment variable VIRTUAL_ENV, used by many tools to determine
 219 # that there is an activated venv.
 220 $env:VIRTUAL_ENV = $VenvDir
 221
 222 if (-not $Env:VIRTUAL_ENV_DISABLE_PROMPT) {
 223
 224     Write-Verbose "Setting prompt to '$Prompt'"
 225
 226     # Set the prompt to include the env name
 227     # Make sure _OLD_VIRTUAL_PROMPT is global
 228     function global:_OLD_VIRTUAL_PROMPT { "" }
 229     Copy-Item -Path function:prompt -Destination function:_OLD_VIRTUAL_PROMPT
 230     New-Variable -Name _PYTHON_VENV_PROMPT_PREFIX -Description "Python virtual environment prompt prefix" -Scope Global -Option ReadOnly -Visibility Public -Value $Prompt
 231
 232     function global:prompt {
 233         Write-Host -NoNewline -ForegroundColor Green "($_PYTHON_VENV_PROMPT_PREFIX) "
 234         _OLD_VIRTUAL_PROMPT
 235     }
 236     $env:VIRTUAL_ENV_PROMPT = $Prompt
 237 }
 238
 239 # Clear PYTHONHOME
 240 if (Test-Path -Path Env:PYTHONHOME) {
 241     Copy-Item -Path Env:PYTHONHOME -Destination Env:_OLD_VIRTUAL_PYTHONHOME
 242     Remove-Item -Path Env:PYTHONHOME
 243 }
 244
 245 # Add the venv to the PATH
 246 Copy-Item -Path Env:PATH -Destination Env:_OLD_VIRTUAL_PATH
 247 $Env:PATH = "$VenvExecDir$([System.IO.Path]::PathSeparator)$Env:PATH"