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 $Prompt
58 )
59
60 <# Function declarations --------------------------------------------------- #>
61
62 <#
63 .Synopsis
64 Remove all shell session elements added by the Activate script, including the
65 addition of the virtual environment's Python executable from the beginning of
66 the PATH variable.
67
68 .Parameter NonDestructive
69 If present, do not remove this function from the global namespace for the
70 session.
71
72 #>
global:deactivate([switch]$NonDestructive)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 #>
Get-PyVenvConfig([String] $ConfigDir)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
global:_OLD_VIRTUAL_PROMPT()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 $Prompt
231
global:prompt()232 function global:prompt {
233 Write-Host -NoNewline -ForegroundColor Green "($_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"
248