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
41 #>
42 Param(
43 [Parameter(Mandatory = $false)]
44 [String]
45 $VenvDir,
46 [Parameter(Mandatory = $false)]
47 [String]
48 $Prompt
49 )
50
51 <# Function declarations --------------------------------------------------- #>
52
53 <#
54 .Synopsis
55 Remove all shell session elements added by the Activate script, including the
56 addition of the virtual environment's Python executable from the beginning of
57 the PATH variable.
58
59 .Parameter NonDestructive
60 If present, do not remove this function from the global namespace for the
61 session.
62
63 #>
global:deactivate([switch]$NonDestructive)64 function global:deactivate ([switch]$NonDestructive) {
65 # Revert to original values
66
67 # The prior prompt:
68 if (Test-Path -Path Function:_OLD_VIRTUAL_PROMPT) {
69 Copy-Item -Path Function:_OLD_VIRTUAL_PROMPT -Destination Function:prompt
70 Remove-Item -Path Function:_OLD_VIRTUAL_PROMPT
71 }
72
73 # The prior PYTHONHOME:
74 if (Test-Path -Path Env:_OLD_VIRTUAL_PYTHONHOME) {
75 Copy-Item -Path Env:_OLD_VIRTUAL_PYTHONHOME -Destination Env:PYTHONHOME
76 Remove-Item -Path Env:_OLD_VIRTUAL_PYTHONHOME
77 }
78
79 # The prior PATH:
80 if (Test-Path -Path Env:_OLD_VIRTUAL_PATH) {
81 Copy-Item -Path Env:_OLD_VIRTUAL_PATH -Destination Env:PATH
82 Remove-Item -Path Env:_OLD_VIRTUAL_PATH
83 }
84
85 # Just remove the VIRTUAL_ENV altogether:
86 if (Test-Path -Path Env:VIRTUAL_ENV) {
87 Remove-Item -Path env:VIRTUAL_ENV
88 }
89
90 # Just remove the _PYTHON_VENV_PROMPT_PREFIX altogether:
91 if (Get-Variable -Name "_PYTHON_VENV_PROMPT_PREFIX" -ErrorAction SilentlyContinue) {
92 Remove-Variable -Name _PYTHON_VENV_PROMPT_PREFIX -Scope Global -Force
93 }
94
95 # Leave deactivate function in the global namespace if requested:
96 if (-not $NonDestructive) {
97 Remove-Item -Path function:deactivate
98 }
99 }
100
101 <#
102 .Description
103 Get-PyVenvConfig parses the values from the pyvenv.cfg file located in the
104 given folder, and returns them in a map.
105
106 For each line in the pyvenv.cfg file, if that line can be parsed into exactly
107 two strings separated by `=` (with any amount of whitespace surrounding the =)
108 then it is considered a `key = value` line. The left hand string is the key,
109 the right hand is the value.
110
111 If the value starts with a `'` or a `"` then the first and last character is
112 stripped from the value before being captured.
113
114 .Parameter ConfigDir
115 Path to the directory that contains the `pyvenv.cfg` file.
116 #>
Get-PyVenvConfig([String] $ConfigDir)117 function Get-PyVenvConfig(
118 [String]
119 $ConfigDir
120 ) {
121 Write-Verbose "Given ConfigDir=$ConfigDir, obtain values in pyvenv.cfg"
122
123 # Ensure the file exists, and issue a warning if it doesn't (but still allow the function to continue).
124 $pyvenvConfigPath = Join-Path -Resolve -Path $ConfigDir -ChildPath 'pyvenv.cfg' -ErrorAction Continue
125
126 # An empty map will be returned if no config file is found.
127 $pyvenvConfig = @{ }
128
129 if ($pyvenvConfigPath) {
130
131 Write-Verbose "File exists, parse `key = value` lines"
132 $pyvenvConfigContent = Get-Content -Path $pyvenvConfigPath
133
134 $pyvenvConfigContent | ForEach-Object {
135 $keyval = $PSItem -split "\s*=\s*", 2
136 if ($keyval[0] -and $keyval[1]) {
137 $val = $keyval[1]
138
139 # Remove extraneous quotations around a string value.
140 if ("'""".Contains($val.Substring(0,1))) {
141 $val = $val.Substring(1, $val.Length - 2)
142 }
143
144 $pyvenvConfig[$keyval[0]] = $val
145 Write-Verbose "Adding Key: '$($keyval[0])'='$val'"
146 }
147 }
148 }
149 return $pyvenvConfig
150 }
151
152
153 <# Begin Activate script --------------------------------------------------- #>
154
155 # Determine the containing directory of this script
156 $VenvExecPath = Split-Path -Parent $MyInvocation.MyCommand.Definition
157 $VenvExecDir = Get-Item -Path $VenvExecPath
158
159 Write-Verbose "Activation script is located in path: '$VenvExecPath'"
160 Write-Verbose "VenvExecDir Fullname: '$($VenvExecDir.FullName)"
161 Write-Verbose "VenvExecDir Name: '$($VenvExecDir.Name)"
162
163 # Set values required in priority: CmdLine, ConfigFile, Default
164 # First, get the location of the virtual environment, it might not be
165 # VenvExecDir if specified on the command line.
166 if ($VenvDir) {
167 Write-Verbose "VenvDir given as parameter, using '$VenvDir' to determine values"
168 } else {
169 Write-Verbose "VenvDir not given as a parameter, using parent directory name as VenvDir."
170 $VenvDir = $VenvExecDir.Parent.FullName.TrimEnd("\\/")
171 $VenvDir = $VenvDir.Insert($VenvDir.Length, "/")
172 Write-Verbose "VenvDir=$VenvDir"
173 }
174
175 # Next, read the `pyvenv.cfg` file to determine any required value such
176 # as `prompt`.
177 $pyvenvCfg = Get-PyVenvConfig -ConfigDir $VenvDir
178
179 # Next, set the prompt from the command line, or the config file, or
180 # just use the name of the virtual environment folder.
181 if ($Prompt) {
182 Write-Verbose "Prompt specified as argument, using '$Prompt'"
183 } else {
184 Write-Verbose "Prompt not specified as argument to script, checking pyvenv.cfg value"
185 if ($pyvenvCfg -and $pyvenvCfg['prompt']) {
186 Write-Verbose " Setting based on value in pyvenv.cfg='$($pyvenvCfg['prompt'])'"
187 $Prompt = $pyvenvCfg['prompt'];
188 }
189 else {
190 Write-Verbose " Setting prompt based on parent's directory's name. (Is the directory name passed to venv module when creating the virutal environment)"
191 Write-Verbose " Got leaf-name of $VenvDir='$(Split-Path -Path $venvDir -Leaf)'"
192 $Prompt = Split-Path -Path $venvDir -Leaf
193 }
194 }
195
196 Write-Verbose "Prompt = '$Prompt'"
197 Write-Verbose "VenvDir='$VenvDir'"
198
199 # Deactivate any currently active virtual environment, but leave the
200 # deactivate function in place.
201 deactivate -nondestructive
202
203 # Now set the environment variable VIRTUAL_ENV, used by many tools to determine
204 # that there is an activated venv.
205 $env:VIRTUAL_ENV = $VenvDir
206
207 if (-not $Env:VIRTUAL_ENV_DISABLE_PROMPT) {
208
209 Write-Verbose "Setting prompt to '$Prompt'"
210
211 # Set the prompt to include the env name
212 # Make sure _OLD_VIRTUAL_PROMPT is global
global:_OLD_VIRTUAL_PROMPT()213 function global:_OLD_VIRTUAL_PROMPT { "" }
214 Copy-Item -Path function:prompt -Destination function:_OLD_VIRTUAL_PROMPT
215 New-Variable -Name _PYTHON_VENV_PROMPT_PREFIX -Description "Python virtual environment prompt prefix" -Scope Global -Option ReadOnly -Visibility Public -Value $Prompt
216
global:prompt()217 function global:prompt {
218 Write-Host -NoNewline -ForegroundColor Green "($_PYTHON_VENV_PROMPT_PREFIX) "
219 _OLD_VIRTUAL_PROMPT
220 }
221 }
222
223 # Clear PYTHONHOME
224 if (Test-Path -Path Env:PYTHONHOME) {
225 Copy-Item -Path Env:PYTHONHOME -Destination Env:_OLD_VIRTUAL_PYTHONHOME
226 Remove-Item -Path Env:PYTHONHOME
227 }
228
229 # Add the venv to the PATH
230 Copy-Item -Path Env:PATH -Destination Env:_OLD_VIRTUAL_PATH
231 $Env:PATH = "$VenvExecDir$([System.IO.Path]::PathSeparator)$Env:PATH"
232