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 the _PYTHON_VENV_PROMPT_PREFIX altogether:
100 if (Get-Variable -Name "_PYTHON_VENV_PROMPT_PREFIX" -ErrorAction SilentlyContinue) {
101 Remove-Variable -Name _PYTHON_VENV_PROMPT_PREFIX -Scope Global -Force
102 }
103
104 # Leave deactivate function in the global namespace if requested:
105 if (-not $NonDestructive) {
106 Remove-Item -Path function:deactivate
107 }
108 }
109
110 <#
111 .Description
112 Get-PyVenvConfig parses the values from the pyvenv.cfg file located in the
113 given folder, and returns them in a map.
114
115 For each line in the pyvenv.cfg file, if that line can be parsed into exactly
116 two strings separated by `=` (with any amount of whitespace surrounding the =)
117 then it is considered a `key = value` line. The left hand string is the key,
118 the right hand is the value.
119
120 If the value starts with a `'` or a `"` then the first and last character is
121 stripped from the value before being captured.
122
123 .Parameter ConfigDir
124 Path to the directory that contains the `pyvenv.cfg` file.
125 #>
Get-PyVenvConfig()126 function Get-PyVenvConfig(
127 [String]
128 $ConfigDir
129 ) {
130 Write-Verbose "Given ConfigDir=$ConfigDir, obtain values in pyvenv.cfg"
131
132 # Ensure the file exists, and issue a warning if it doesn't (but still allow the function to continue).
133 $pyvenvConfigPath = Join-Path -Resolve -Path $ConfigDir -ChildPath 'pyvenv.cfg' -ErrorAction Continue
134
135 # An empty map will be returned if no config file is found.
136 $pyvenvConfig = @{ }
137
138 if ($pyvenvConfigPath) {
139
140 Write-Verbose "File exists, parse `key = value` lines"
141 $pyvenvConfigContent = Get-Content -Path $pyvenvConfigPath
142
143 $pyvenvConfigContent | ForEach-Object {
144 $keyval = $PSItem -split "\s*=\s*", 2
145 if ($keyval[0] -and $keyval[1]) {
146 $val = $keyval[1]
147
148 # Remove extraneous quotations around a string value.
149 if ("'""".Contains($val.Substring(0, 1))) {
150 $val = $val.Substring(1, $val.Length - 2)
151 }
152
153 $pyvenvConfig[$keyval[0]] = $val
154 Write-Verbose "Adding Key: '$($keyval[0])'='$val'"
155 }
156 }
157 }
158 return $pyvenvConfig
159 }
160
161
162 <# Begin Activate script --------------------------------------------------- #>
163
164 # Determine the containing directory of this script
165 $VenvExecPath = Split-Path -Parent $MyInvocation.MyCommand.Definition
166 $VenvExecDir = Get-Item -Path $VenvExecPath
167
168 Write-Verbose "Activation script is located in path: '$VenvExecPath'"
169 Write-Verbose "VenvExecDir Fullname: '$($VenvExecDir.FullName)"
170 Write-Verbose "VenvExecDir Name: '$($VenvExecDir.Name)"
171
172 # Set values required in priority: CmdLine, ConfigFile, Default
173 # First, get the location of the virtual environment, it might not be
174 # VenvExecDir if specified on the command line.
175 if ($VenvDir) {
176 Write-Verbose "VenvDir given as parameter, using '$VenvDir' to determine values"
177 }
178 else {
179 Write-Verbose "VenvDir not given as a parameter, using parent directory name as VenvDir."
180 $VenvDir = $VenvExecDir.Parent.FullName.TrimEnd("\\/")
181 Write-Verbose "VenvDir=$VenvDir"
182 }
183
184 # Next, read the `pyvenv.cfg` file to determine any required value such
185 # as `prompt`.
186 $pyvenvCfg = Get-PyVenvConfig -ConfigDir $VenvDir
187
188 # Next, set the prompt from the command line, or the config file, or
189 # just use the name of the virtual environment folder.
190 if ($Prompt) {
191 Write-Verbose "Prompt specified as argument, using '$Prompt'"
192 }
193 else {
194 Write-Verbose "Prompt not specified as argument to script, checking pyvenv.cfg value"
195 if ($pyvenvCfg -and $pyvenvCfg['prompt']) {
196 Write-Verbose " Setting based on value in pyvenv.cfg='$($pyvenvCfg['prompt'])'"
197 $Prompt = $pyvenvCfg['prompt'];
198 }
199 else {
200 Write-Verbose " Setting prompt based on parent's directory's name. (Is the directory name passed to venv module when creating the virutal environment)"
201 Write-Verbose " Got leaf-name of $VenvDir='$(Split-Path -Path $venvDir -Leaf)'"
202 $Prompt = Split-Path -Path $venvDir -Leaf
203 }
204 }
205
206 Write-Verbose "Prompt = '$Prompt'"
207 Write-Verbose "VenvDir='$VenvDir'"
208
209 # Deactivate any currently active virtual environment, but leave the
210 # deactivate function in place.
211 deactivate -nondestructive
212
213 # Now set the environment variable VIRTUAL_ENV, used by many tools to determine
214 # that there is an activated venv.
215 $env:VIRTUAL_ENV = $VenvDir
216
217 if (-not $Env:VIRTUAL_ENV_DISABLE_PROMPT) {
218
219 Write-Verbose "Setting prompt to '$Prompt'"
220
221 # Set the prompt to include the env name
222 # Make sure _OLD_VIRTUAL_PROMPT is global
global:_OLD_VIRTUAL_PROMPT()223 function global:_OLD_VIRTUAL_PROMPT { "" }
224 Copy-Item -Path function:prompt -Destination function:_OLD_VIRTUAL_PROMPT
225 New-Variable -Name _PYTHON_VENV_PROMPT_PREFIX -Description "Python virtual environment prompt prefix" -Scope Global -Option ReadOnly -Visibility Public -Value $Prompt
226
global:prompt()227 function global:prompt {
228 Write-Host -NoNewline -ForegroundColor Green "($_PYTHON_VENV_PROMPT_PREFIX) "
229 _OLD_VIRTUAL_PROMPT
230 }
231 }
232
233 # Clear PYTHONHOME
234 if (Test-Path -Path Env:PYTHONHOME) {
235 Copy-Item -Path Env:PYTHONHOME -Destination Env:_OLD_VIRTUAL_PYTHONHOME
236 Remove-Item -Path Env:PYTHONHOME
237 }
238
239 # Add the venv to the PATH
240 Copy-Item -Path Env:PATH -Destination Env:_OLD_VIRTUAL_PATH
241 $Env:PATH = "$VenvExecDir$([System.IO.Path]::PathSeparator)$Env:PATH"
242