94 lines
3.7 KiB
PowerShell
94 lines
3.7 KiB
PowerShell
#!/usr/bin/env pwsh
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# CASAN L5 Drift Detector - PowerShell port of drift-detect.sh
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# Usage:
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# drift-detect.ps1 <golden-file> <candidate-file> <report-json>
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#
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# Exit codes: 0=pass/warn, 2=drift-fail
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param(
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[Parameter(Mandatory=$true, Position=0)][string]$GoldenFile,
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[Parameter(Mandatory=$true, Position=1)][string]$CandidateFile,
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[Parameter(Mandatory=$true, Position=2)][string]$ReportFile
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)
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$ErrorActionPreference = "Stop"
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$scriptDir = Split-Path $MyInvocation.MyCommand.Path -Parent
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$projectRoot = (Resolve-Path (Join-Path $scriptDir "../../..")).Path
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$l5LogDir = Join-Path $projectRoot ".specify/logs/level5"
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foreach ($d in @($l5LogDir, (Split-Path $ReportFile -Parent))) {
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if ($d -and !(Test-Path $d)) { New-Item -ItemType Directory -Force -Path $d | Out-Null }
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}
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if (!(Test-Path $GoldenFile)) { Write-Error "Golden file not found: $GoldenFile"; exit 1 }
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if (!(Test-Path $CandidateFile)) { Write-Error "Candidate file not found: $CandidateFile"; exit 1 }
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function Get-Sha256 ([string]$text) {
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$bytes = [System.Text.Encoding]::UTF8.GetBytes($text)
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$hash = [System.Security.Cryptography.SHA256]::Create().ComputeHash($bytes)
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return ($hash | ForEach-Object { $_.ToString("x2") }) -join ""
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}
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# Levenshtein-inspired similarity via longest common subsequence on words
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function Get-SimilarityRatio ([string]$a, [string]$b) {
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$wordsA = $a -split '\s+' | Where-Object { $_ }
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$wordsB = $b -split '\s+' | Where-Object { $_ }
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if ($wordsA.Count -eq 0 -and $wordsB.Count -eq 0) { return 1.0 }
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if ($wordsA.Count -eq 0 -or $wordsB.Count -eq 0) { return 0.0 }
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# Simple Jaccard similarity on word sets (fast, portable, no python needed)
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$setA = [System.Collections.Generic.HashSet[string]]$wordsA
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$setB = [System.Collections.Generic.HashSet[string]]$wordsB
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$intersection = ($setA | Where-Object { $setB.Contains($_) }).Count
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$union = ($setA + $setB | Sort-Object -Unique).Count
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return [math]::Round($intersection / [math]::Max($union, 1), 4)
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}
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$golden = Get-Content $GoldenFile -Raw -Encoding UTF8
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$candidate = Get-Content $CandidateFile -Raw -Encoding UTF8
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if (!$golden) { $golden = "" }
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if (!$candidate) { $candidate = "" }
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$similarity = Get-SimilarityRatio $golden $candidate
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$lenGolden = [math]::Max($golden.Length, 1)
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$lengthDelta = [math]::Round([math]::Abs($candidate.Length - $golden.Length) / $lenGolden, 4)
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$driftStatus = "pass"
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$driftAction = "allow"
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if ($similarity -lt 0.70 -or $lengthDelta -gt 0.50) {
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$driftStatus = "fail"; $driftAction = "block_or_fallback"
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} elseif ($similarity -lt 0.85 -or $lengthDelta -gt 0.30) {
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$driftStatus = "warn"; $driftAction = "require_review"
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}
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$timestamp = (Get-Date).ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ssZ")
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$goldenHash = Get-Sha256 $golden
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$candidHash = Get-Sha256 $candidate
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$report = @"
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{
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"timestamp": "$timestamp",
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"harness": "L5-drift-detection",
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"status": "$driftStatus",
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"action": "$driftAction",
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"similarity_ratio": $similarity,
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"length_delta_ratio": $lengthDelta,
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"golden_hash": "$goldenHash",
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"candidate_hash": "$candidHash",
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"golden_file": "$GoldenFile",
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"candidate_file": "$CandidateFile"
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}
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"@
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Set-Content -Path $ReportFile -Value $report -Encoding UTF8
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# Append to L5 log
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$logLine = "{`"timestamp`":`"$timestamp`",`"harness`":`"L5-drift-detection`",`"status`":`"$driftStatus`",`"similarity`":$similarity,`"length_delta`":$lengthDelta,`"golden`":`"$GoldenFile`",`"candidate`":`"$CandidateFile`"}"
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Add-Content -Path (Join-Path $l5LogDir "drift.jsonl") -Value $logLine -Encoding UTF8
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Write-Output "DRIFT_$($driftStatus.ToUpper()) similarity=$similarity length_delta=$lengthDelta report=$ReportFile"
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if ($driftStatus -eq "fail") { exit 2 }
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exit 0
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