I have a file with a group of function definitions and variable assignments, some of which are only used to help other functions or definitions. Is it possible to hide these from the Import-Module command such that the user cannot see them?
Alternatively, is there a method for manually declaring exports?
It seems you haven't been exporting your module members manually. Use the Export-ModuleMember Cmdlet to do so. If you do not export a member, it won't be seen by the user.
To export a function/cmdlet/alias/variable, write
Export-ModuleMember -Function MyFunction -Alias MyAlias -Cmdlet MyCmdlet -Variable MyVariable
at the bottom of your module file.
Related
I've defined a variable in a psm1 file but when I try to access it in another script, after importing the module, I'm not seeing the value set in the psm1 file.
globals.psm1
$blah = "hello world"
my-script.ps1
Import-Module "$PSScriptRoot\globals.psm1" -Force -Verbose
Write-Output "blah: ${blah}"
output
PS C:\blah> .\my-script.ps1
VERBOSE: Loading module from path 'C:\blah\globals.psm1'.
blah: ''
I thought all variables get exported by default. I must be interrupting this wrong:
Specifies the variables that the module exports to the caller's session state. Wildcard characters are permitted. By default, all variables ('*') are exported
source: MSFT Docs -> How to write a PowerShell module manifest
(CTRL + F on 'VariablesToExport' to find the quoted text)
And yes, if I export the variable, I can access it but the documentation says: 'By default, all varialbes ('*') are exported so what am I doing wrong or misunderstanding? 🤔
globals.psm1
$blah = "hello world"
Export-ModuleMember -Variable blah
Your module is not using a module manifest (a companion .psd1 file whose RootModule entry points to your .psm1 file in the case of script modules), whereas the documentation you quote pertains to module manifest-based modules.
If a module consists only of a .psm1 file, and that file contains no Export-ModuleMember calls, the following rule applies:
Only functions and aliases are automatically exported.
Conversely, this means: in order to also export variables, you must use an Export-ModuleMember call - and if you do, the slate is wiped clean, so to speak, and you must explicitly specify all definitions you want to export (in the simplest case, use Export-ModuleMember -Function * -Alias * -Variable *).
Also, be sure to place this call at the end of your .psm1 file, to ensure that all definitions to export have already been defined.
Caveat, if a manifest (.psd1) is used:
The manifest's *ToExport keys apply on top of what the .psm1 file - implicitly or explicitly - exports, i.e. you can use it to further narrow what is to be exported, by explicitly enumerating the elements to export, which not only makes the module more self-describing, but also helps performance when PowerShell auto-discovers the commands in available, but not-(yet)-imported modules.
Therefore, if a manifest-based module wants to export variables, it too must have an explicit Export-ModuleMember call in its .psm1 file, with the manifest potentially narrowing down what variables are ultimately to be exported.
Generally, exporting variables from modules is best avoided, because:
it increases the risk of name collisions with variables of the same name defined elsewhere.
discovering which variables are exported by what module isn't as well-known as use of Get-Command is in order to determine what module a given function, cmdlet, or alias comes from. This is because (a) modules that export variables are rare and users generally don't expect it, and (b) the Get-Variable cmdlet - which can tell you what module a variable is defined in - isn't often used in practice.
To see which definitions a given module exports, pass -Verbose to the Import-Module call that imports it. Additionally, pass -Force in order to force re-loading of an already imported module.
I'm new with PowerShell and I've just started to create my own module.
I created the script & manifest files and placed them into the directory C:\Program Files\WindowsPowerShell\Modules\ who is one listed of the $env:PSModulePath command.
I can import and remove the module as well but it's not recognized as an applet or command when I try to call one of the function.
I use the Import-Module command :
Import-Module MyModule
My script file is something like this :
function MyFunction() {}
Export-ModuleMember -Function *
And my manifest looks like this :
FunctionsToExport = '*'
Do I need to write all of the exported functions into the manifest ?
Thank you for your help.
Ok so after a few hours I found the answer :
ExportedCommand empty custom module PowerShell
You need to put RootModule = 'MyModule.psm1' into the manifest.
Have a nice day !
for me, the following ( based on Mica's answer) worked:
Change the RootModule as Mica suggested in the psd1 file to the psm1 file.
Use the Import-Module -Force MyModule command
(with the '-Force' flag:
"This parameter causes a module to be loaded, or reloaded, over top of the current one." as said at https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/import-module?view=powershell-7.1#examples)
To export everything:
Module manifest (.psd1):
FunctionsToExport = '*'
Module script file (.psm1):
Export-ModuleMember -Function *
To restrict what gets exported:
Module manifest (.psd1):
FunctionsToExport = 'Foo', 'Bar'
Module script file (.psm1):
Export-ModuleMember -Function Foo, Bar
Note that if quotes are not used in this specific way, it will not work, and no error will be reported.
I have a psm1 module with several functions. I only want to expose some of the functions, so I used "Export-ModuleMember -Function " and everything was fine.
Now I want to add a manifest, so I removed the Export-ModuleMember cmdlet and put the function names under the FunctionsToExport section of the psd1 file.
When I import the module, I can tab-complete the functions, but when I try to use them, ps says:
Test-Function : The term 'Test-Function' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
I also tried putting Export-ModuleMember -Function * into the psm1, but that didn't help.
The psm1 and psd1 files are named the same and are in the root of the module.
Thoughts? Thanks.
I found the answer. I had forgotten to un-comment the RooteModule node. Once I did that (and had module.psm1 as the value), the exported commands showed up in the "Get-Module module" output.
I would suspect that PowerShell caching mechanism is involved here. Try to run:
Get-Module -ListAvailable -Refresh
I recommend very good article on that subject written by PowerShell MVP Tobias Weltner.
How do I retrieve a variable exported from my module after an import?
# in mymodule.psm1
$myVar = New-Object VarClass
#assume a function or two here.
Export-Modulemember -Function * -Variable *
# in myScript.ps1 after module import
# how do I reference this variable?
$myScriptVar = $myVar
Sorry for the basic question, I cannot find any examples on this simple problem.
You must explicitly state the functions and variables in the export module-member cmdlet when exporting both. My problem was that I had a functions as well.
From powershell documentation:
If you want to export a variable, in addition to exporting the
functions in a module, the Export-ModuleMember command must include
the names of all of the functions and the name of the variable.
In this instance I have to have the following in my module:
Export-Modulemember -Function Verb-Noun -Variable myVar
I got stuck because the same is true in the manifest, you cannot use a wildcard if you're exporting both.
# Functions to export from this module
FunctionsToExport = 'Verb-Noun'
# Variables to export from this module
VariablesToExport = 'myVar'
Steps to reproduce:
Create a TestAlias module in \WindowsPowerShell\Modules\TestAlias\TestAlias.psm1 with the following function and alias:
function foo
{ write-output 'foo' }
New-Alias -name bar -value foo
From a PowerShell session:
import-module TestAlias
bar
The term 'bar' is not recognized as the name of a cmdlet, function, script file, or operable program...
You can use
Export-ModuleMember -Function * -Alias *
to export all functions and aliases.
By default, Windows PowerShell modules only export commands (functions or cmdletS), and not variables or aliases.
I'll go into a little more detail about why this is.
The short answers is that aliases, while convenient when writing one liners, are a barrier to understanding a script or a module. They are icing on the cake of a good cmdlet, but the core thing to expose is the good cmdlet. Aliases make it more difficult for a user reading your script to figure out what you're trying to do (Set-Content is a lot easier to understand than sc). Variables can be even worse to expose, as they can easily be set to unexpected values and as there is very little to help a user of your module figure out that they are there. Because commands are easily discoverable (Get-Command -Module FOO) and easier to explore (with Get-Help), the default that a module will export is only commands. As with most other things in PowerShell, you can override it if you choose, but by default commands are the only thing that are exported from a module.
Hope this Helps
Use Export-ModuleMember in the PSM1 file to export the Alias
Export-ModuleMember -function foo -Alias bar