ci(): Add linter check (#27)

Run the linter over the powershell code.

Author: donny-dont

.drone.yml

@@ -21,6 +21,14 @@ steps:
     status:
     - failure
 
+- name: linter
+  image: mcr.microsoft.com/powershell:alpine-3.14
+  commands:
+  - pwsh ./Invoke-Linter.ps1 -exitCodeOnError
+  environment:
+    # Disable debugging and profiling
+    COMPlus_EnableDiagnostics: 0
+
 trigger:
   ref:
   - refs/heads/master

Invoke-Linter.ps1

@@ -0,0 +1,71 @@
+param(
+    [switch]$exitCodeOnError = $false,
+    [string]$moduleRoot
+)
+
+$ErrorActionPreference = 'Stop';
+
+# Import the PowerShell modules locally
+if (-not ($moduleRoot)) {
+    $moduleRoot = Join-Path $PSScriptRoot -ChildPath 'psmodules';
+}
+
+if (-not (Test-Path -Path $moduleRoot)) {
+    New-Item -Path $moduleRoot -ItemType 'directory' | Out-Null;
+}
+
+function Import-ModuleLocally {
+    param(
+        [string]$name,
+        [string]$version
+    )
+
+    Write-Information -MessageData ('Importing {0} v{1}' -f $name,$version) -InformationAction Continue;
+    if (Get-Module -Name $name) {
+        Remove-Module -Name $name;
+    }
+
+    $importModule = Join-Path $moduleRoot -ChildPath $name | `
+         Join-Path -ChildPath $version | `
+         Join-Path -ChildPath ($name + '.psd1');
+
+    if (-not (Test-Path -Path $importModule)) {
+        Write-Information -MessageData ('Saving module {0}' -f $name) -InformationAction Continue;
+        Save-Module $name -Path $moduleRoot -Repository PSGallery -RequiredVersion $version;
+    }
+
+    Import-Module $importModule;
+}
+
+Import-ModuleLocally -Name PSScriptAnalyzer -Version 1.20.0;
+
+# Use Invoke-Formatter on all code
+# Using -Exclude breaks the -Filter functionality so a regex using Where-Object is used instead
+$psScripts = Get-ChildItem -Path $PSScriptRoot -Exclude 'psmodules' | `
+     Get-ChildItem -Recurse | `
+     Where-Object { $_.FullName -match '.*\.ps1$' }
+$issues = 0;
+$files = 0;
+
+foreach ($script in $psScripts) {
+    $files++;
+    $scriptPath = $script.FullName;
+
+    $records = Invoke-ScriptAnalyzer -Path $scriptPath `
+         -Exclude PSUseSingularNouns,PSAvoidUsingInvokeExpression,PSUseShouldProcessForStateChangingFunctions `
+
+    Write-Information -MessageData ('Analyzing {0}' -f $scriptPath) -InformationAction Continue;
+
+    if ($records) {
+        foreach ($record in $records) {
+            $issues++;
+            Write-Information -MessageData ('{0}:{1}: {2} {3}' -f $record.ScriptName,$record.Line,$record.RuleName,$record.Message) -InformationAction Continue;
+        }
+    }
+}
+
+Write-Information -MessageData ('Found {0} issues across {1} files' -f $issues,$files) -InformationAction Continue;
+
+if ($issues -gt 0 -and $exitCodeOnError) {
+    exit -1;
+}