Add PsTypeName post #14

Merged
OCram85 merged 12 commits from PSType into master 2022-03-17 11:43:18 +01:00
7 changed files with 278 additions and 5 deletions

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@ -53,11 +53,25 @@ steps:
repo: ocram85/blog repo: ocram85/blog
tags: "next" tags: "next"
dockerfile: Dockerfile dockerfile: Dockerfile
build_args:
- NODE_BASE=lts-buster-slim
- NGINX_BASE=1.21.6-alpine
- name: "Trivy (next)" - name: "Trivy (next)"
image: aquasec/trivy image: aquasec/trivy
failure: ignore
commands: commands:
- "trivy image --exit-code 1 --no-progress ocram85/blog:next" - |
trivy image \
--severity UNKNOWN,LOW,MEDIUM \
--no-progress \
ocram85/blog:next
- |
trivy image \
--exit-code 1 \
--severity HIGH,CRITICAL \
--no-progress \
ocram85/blog:next
- name: "Trigger Service Update" - name: "Trigger Service Update"
image: ocram85/portainer-serviceupdate image: ocram85/portainer-serviceupdate
@ -100,11 +114,24 @@ steps:
repo: ocram85/blog repo: ocram85/blog
auto_tag: true auto_tag: true
dockerfile: Dockerfile dockerfile: Dockerfile
build_args:
- NODE_BASE=lts-buster-slim
- NGINX_BASE=1.21.6-alpine
- name: "Trivy (latest)" - name: "Trivy (latest)"
image: aquasec/trivy image: aquasec/trivy
commands: commands:
- "trivy image --exit-code 1 --no-progress ocram85/blog:latest" - |
trivy image \
--severity UNKNOWN,LOW,MEDIUM \
--no-progress \
ocram85/blog:latest
- |
trivy image \
--exit-code 1 \
--severity HIGH,CRITICAL \
--no-progress \
ocram85/blog:latest
- name: "Trigger Service Update" - name: "Trigger Service Update"
image: ocram85/portainer-serviceupdate image: ocram85/portainer-serviceupdate

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@ -1,4 +1,8 @@
FROM node:lts-buster-slim as builder # Build ARGS for base image versions
ARG NODE_BASE=lts-buster-slim
ARG NGINX_BASE=1.21.6-alpine
FROM node:${NODE_BASE} as builder
COPY . /src COPY . /src
#RUN ls -la #RUN ls -la
WORKDIR /src WORKDIR /src
@ -6,7 +10,7 @@ WORKDIR /src
RUN npm install \ RUN npm install \
&& npm run build && npm run build
FROM nginx:1.21.5-alpine FROM nginx:${NGINX_BASE} as prod
LABEL maintainer="marco.blessing@googlemail.com" LABEL maintainer="marco.blessing@googlemail.com"
HEALTHCHECK --interval=15s --timeout=5s \ HEALTHCHECK --interval=15s --timeout=5s \
CMD wget --no-verbose --tries=1 --spider http://localhost:80/ || exit 1 CMD wget --no-verbose --tries=1 --spider http://localhost:80/ || exit 1

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@ -3,6 +3,9 @@ title: "{{ replace .Name "-" " " | title }}"
date: {{ .Date }} date: {{ .Date }}
draft: true draft: true
categories: ['']
tags: ['']
# lastmod: {{ .Date}} # lastmod: {{ .Date}}
# showDateUpdated: true # showDateUpdated: true

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@ -47,6 +47,7 @@ dateFormat = "2 January 2006"
# { slack = "https://workspace.url/team/userid" }, # { slack = "https://workspace.url/team/userid" },
# { snapchat = "https://snapchat.com/add/username" }, # { snapchat = "https://snapchat.com/add/username" },
# { soundcloud = "https://soundcloud.com/username" }, # { soundcloud = "https://soundcloud.com/username" },
{ stack-overflow = "https://stackoverflow.com/users/5222635/ocram85" },
# { steam = "https://steamcommunity.com/profiles/userid" }, # { steam = "https://steamcommunity.com/profiles/userid" },
# { telegram = "https://t.me/username" }, # { telegram = "https://t.me/username" },
# { tiktok = "https://tiktok.com/@username" }, # { tiktok = "https://tiktok.com/@username" },

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@ -0,0 +1,238 @@
---
title: 'Parameter Validation with PSTypeName'
date: 2022-03-16T09:24:56+01:00
#draft: true
categories: ['PowerShell']
tags: ['parameter', 'validation', 'PSTypeName']
# lastmod: 2022-03-16T09:24:56+01:00
# showDateUpdated: true
# custom overrides for pages
# showDate: false
# showAuthor: false
# showWordCount: false
# showReadingTime: false
# showTableOfContents: false
# showTaxonomies: true
# showEdit: false
# sharingLinks: [null]
---
![ship](ship.jpg 'Photo by [Rod Long](https://unsplash.com/@rodlong) on [Unsplash](https://unsplash.com)')
## 🖼️ Intro
This post explains how to use `PSCustomObject`s as function parameters. We compare the basic usage with an
advanced one using the `[PSTypeName()]` parameter attribute.
## 🗑️ Well-Known Workflow
So let's start with a common object definition how it is used with a function:
```powershell
$Rocinante = [PSCustomObject]@{
Owner = 'Martian Congressional Republic Navy'
Type = 'Light Frigate'
Class = 'Corvette'
Registry = 'ECF-270'
HullNumber = '158'
LengthInMeter = 46
Name = 'Rocinante'
}
```
As you can see, a `PSCustomObject` has still the the same class type and just differs by its note properties.
```bash
> $Rocinante | Get-Member
TypeName: System.Management.Automation.PSCustomObject
Name MemberType Definition
---- ---------- ----------
Equals Method bool Equals(System.Object obj)
GetHashCode Method int GetHashCode()
GetType Method type GetType()
ToString Method string ToString()
Class NoteProperty string Class=Corvette
HullNumber NoteProperty string HullNumber=158
LengthInMeter NoteProperty int LengthInMeter=46
Name NoteProperty string Name=Rocinante
Owner NoteProperty string Owner=Martian Congressional Republic Navy
Registry NoteProperty string Registry=ECF-270
Type NoteProperty string Type=Light Frigate
> $Rocinante.PSObject.TypeNames
System.Management.Automation.PSCustomObject
System.Object
```
So we can use the out object as an function parameter.
```powershell
function Invoke-Launch {
[CmdletBinding()]
param (
[Parameter(Mandatory = $true)]
[ValidateNotNullOrEmpty()]
[PSCustomObject]$Ship
)
begin {}
process {
# Manual input validation for $Ship
# test if all needed properties are present.
$DockLength = 50
if ($Ship.LengthInMeter -gt $DockLength) {
Write-Error -Message "Ship doesn't fit in the docking station." -ErrorAction 'Stop'
}
# ...
# ...
}
end {}
}
```
This common pattern could fail whenever someone changes your object properties. If the _LengthInMeter_ property is missing you ran into an error. E.g.:
```console
> $Rocinante = [PSCustomObject]@{ foo = 'bar' }
> Invoke-Launch -Ship $Rocinante
```
{{< note >}}
Keep in mind - Because we are using here custom objects and not class instances, we can not use `Rocinante` as a parameter type like `[Rocinante]$Ship` which would solve this immediately.
{{< /note >}}
To fix this we can use the `[PSTypeName()]` parameter attribute, to ensure an object with the correct type name is used. This doesn't verify your parameters but minimize the risk for using invalid parameter objects.
## 🛡️ PSTypeName Usage
Let's first modify the object creation and use a custom type name.
```powershell
$Rocinante = [PSCustomObject]@{
# You can use special property 'PSTypeName'
# to set it implicit within the creation.
PSTypeName = 'Ship.Corvette.LightFrigate'
Owner = 'Martian Congressional Republic Navy'
Type = 'Light Frigate'
Class = 'Corvette'
Registry = 'ECF-270'
HullNumber = '158'
LengthInMeter = 46
Name = 'Rocinante'
}
# Legacy syntax for injection a custom type name
# $Rocinante.PSObject.TypeNames.insert(0,'Ship.Corvette.LightFrigate')
```
```bash
> $Rocinante | Get-Member
TypeName: Ship.Corvette.LightFrigate
Name MemberType Definition
---- ---------- ----------
Equals Method bool Equals(System.Object obj)
GetHashCode Method int GetHashCode()
GetType Method type GetType()
ToString Method string ToString()
Class NoteProperty string Class=Corvette
HullNumber NoteProperty string HullNumber=158
LengthInMeter NoteProperty int LengthInMeter=46
Name NoteProperty string Name=Rocinante
Owner NoteProperty string Owner=Martian Congressional Republic Navy
Registry NoteProperty string Registry=ECF-270
Type NoteProperty string Type=Light Frigate
> $Rocinante.PSObject.TypeNames
Ship.Corvette.LightFrigate
System.Management.Automation.PSCustomObject
System.Object
```
Now we can replace the `[PSCustomObject]` parameter type by `[PSTypeName()]`
```powershell
function Invoke-Launch {
[CmdletBinding()]
param (
[Parameter(Mandatory = $true)]
[ValidateNotNullOrEmpty()]
[PSTypeName('Ship.Corvette.LightFrigate')]$Ship
)
begin {}
process {
$DockLength = 50
if ($Ship.LengthInMeter -gt $DockLength) {
Write-Error -Message "Ship doesn't fit in the docking station." -ErrorAction 'Stop'
}
# ...
# ...
}
end {}
}
```
## 💭 Final Thoughts
Over time, your PowerShell functions become more and more complex. You will reach a point where you start using
objects as parameters. This is where the PSTypeName parameter attribute shown can help you.
In my experience, the ability to create custom classes _(introduced in PowerShell 5)_ is rarely used for this.
Most PowerShell users I know have a SysOp or DevOps background. Few come from software development and try to use
OOP paradigms and patterns.
Therefore I would also avoid using complex classes, especially if they use not only properties but also methods.
Like already mentioned `PSTypeName` just tests the used type name and not your definition details.
You should consider creating a your objects within a wrapper function to mimic a class constructor:
```powershell
function New-LightFrigate {
[CmdletBinding()]
[OutputType('Ship.Corvette.LightFrigate')]
param (
[Parameter(Mandatory = $true)]
[ValidateNotNullOrEmpty()]
[string]$Registry,
[Parameter(Mandatory = $true)]
[ValidateNotNullOrEmpty()]
[string]$HullNumber,
[Parameter(Mandatory = $true)]
[ValidateNotNullOrEmpty()]
[string]$Name
)
begin {}
process {
$Ship = [PSCustomObject]@{
PSTypeName = 'Ship.Corvette.LightFrigate'
Owner = 'Martian Congressional Republic Navy'
Type = 'Light Frigate'
Class = 'Corvette'
Registry = $Registry
HullNumber = $HullNumber
LengthInMeter = 46
Name = $Name
}
Write-Output $Ship
}
end {}
}
$Rocinante = New-LightFrigate -Name 'Rocinante' -Registry 'DE-MB2' -HullNumber '158'
```

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Subproject commit 480492a976a577d5ee563a69b57c7b45b519a23c Subproject commit 56fc286336c136cbc5cc094769721b4393dd7863