rb/scripts/od-backup-check.ps1

<#
.SYNOPSIS
  Read-only health check of the latest Open Dental cold backup: freshness,
  completeness, and size sanity. Optionally pings a dead-man's-switch heartbeat
  URL on success so an external monitor alerts when a backup silently stops.

.DESCRIPTION
  Points at the backup destination root (<DEST>) produced by od-db-backup.ps1,
  finds the newest od-backup-<timestamp> folder, and verifies it is:
    - FRESH      : written within the max-age window (default 24h)
    - COMPLETE   : has data\, (optionally) OpenDentImages\, MANIFEST.txt, and a
                   backup.log that ends in success with no ERROR/CRITICAL lines
    - SANE SIZE  : data\ isn't near-empty, and isn't a fraction of the prior run
  Prints a clear PASS/FAIL summary, appends a line to <DEST>\backup-check.log,
  and — if healthy and a heartbeat URL was given — pings it. Pinging ONLY on
  success is deliberate: if this check fails, crashes, or the whole server is
  off, no ping arrives and the external monitor raises the alarm. "No news" is
  never mistaken for good news.

  Fully READ-ONLY: it does not touch the database, the service, or the backup
  files. Safe to schedule and safe to run ad hoc.

.NOTES
  Manual spot-check:
      irm rb.godwinsystems.com/scripts/od-backup-check.ps1 | iex

  For unattended monitoring, schedule a filled-in LOCAL copy (with <DEST> and the
  heartbeat URL baked in) — keep that copy in the private tier, not here. See
  od-backup-schedule.md.

  iex-safe: uses `return`, never `exit` (which would close an interactive
  session). PUBLIC REPO: no client specifics hard-coded; prompt at run time.

  Provided as-is, without warranty. This runs in your session via `iex` —
  read it before you run it. You are responsible for the systems you run
  it on. See LICENSE.
#>

$ErrorActionPreference = 'Stop'

Write-Host '== Open Dental: backup health check (read-only) ==' -ForegroundColor Cyan

# --- Prompts (no param block; iex-safe) ---
$destRoot = Read-Host 'Backup destination root (<DEST>, e.g. E:\OD-Backups)'
if (-not (Test-Path $destRoot)) {
    Write-Warning "Destination not found: $destRoot"
    return
}
$maxAgeInput = Read-Host 'Max age (hours) for a healthy backup [24]'
$maxAgeHrs   = if ($maxAgeInput -match '^\d+$') { [int]$maxAgeInput } else { 24 }
$expectImages = (Read-Host 'Should each backup include an OpenDentImages folder? (Y/n)') -ne 'n'
$heartbeat    = Read-Host 'Heartbeat/ping URL to hit on SUCCESS (<HEARTBEAT_URL>) [blank to skip]'

$problems = New-Object System.Collections.Generic.List[string]
function Fail($msg) { $problems.Add($msg) }

function Get-DirSizeBytes($path) {
    if (-not (Test-Path $path)) { return $null }
    (Get-ChildItem -LiteralPath $path -Recurse -Force -File -ErrorAction SilentlyContinue |
        Measure-Object -Property Length -Sum).Sum
}

# --- Find the newest backup folder ---
$folders = @(Get-ChildItem -LiteralPath $destRoot -Directory -Filter 'od-backup-*' -ErrorAction SilentlyContinue |
             Sort-Object LastWriteTime -Descending)
if ($folders.Count -eq 0) {
    Fail "No od-backup-* folders found under $destRoot."
}
else {
    $latest = $folders[0]
    Write-Host "Latest backup: $($latest.Name)  ($($latest.LastWriteTime))" -ForegroundColor Green

    # 1) Freshness
    $ageHrs = [math]::Round(((Get-Date) - $latest.LastWriteTime).TotalHours, 1)
    if ($ageHrs -gt $maxAgeHrs) {
        Fail "Stale: newest backup is $ageHrs h old (limit $maxAgeHrs h). Backup may have stopped running."
    }
    if (((Get-Date) - $latest.LastWriteTime).TotalMinutes -lt 5) {
        Write-Warning 'Newest folder was written <5 min ago — a backup may be in progress. Re-check after it finishes.'
    }

    # 2) Completeness
    $dataDir  = Join-Path $latest.FullName 'data'
    $imgDir   = Join-Path $latest.FullName 'OpenDentImages'
    $manifest = Join-Path $latest.FullName 'MANIFEST.txt'
    $logFile  = Join-Path $latest.FullName 'backup.log'

    if (-not (Test-Path $dataDir))  { Fail "Missing data\ directory in $($latest.Name)." }
    if (-not (Test-Path $manifest)) { Fail "Missing MANIFEST.txt (backup may not have completed) in $($latest.Name)." }
    if ($expectImages -and -not (Test-Path $imgDir)) {
        Fail "Missing OpenDentImages\ in $($latest.Name) — a DB-only backup loses all documents."
    }
    if (Test-Path $logFile) {
        $tail = Get-Content -LiteralPath $logFile -Tail 40 -ErrorAction SilentlyContinue
        if ($tail -match 'ERROR|CRITICAL') { Fail "backup.log contains ERROR/CRITICAL lines in $($latest.Name)." }
        if (-not ($tail -match 'completed successfully')) {
            Fail "backup.log does not show a successful completion in $($latest.Name)."
        }
    } else {
        Fail "Missing backup.log in $($latest.Name)."
    }

    # 3) Size sanity
    $dataBytes = Get-DirSizeBytes $dataDir
    if ($null -ne $dataBytes) {
        $dataMB = [math]::Round($dataBytes / 1MB, 1)
        Write-Host "  data\ size: $dataMB MB"
        if ($dataBytes -lt 1MB) { Fail "data\ is only $dataMB MB — implausibly small; likely a broken/partial backup." }
        if ($folders.Count -gt 1) {
            $prevData = Get-DirSizeBytes (Join-Path $folders[1].FullName 'data')
            if ($prevData -and $dataBytes -lt ($prevData * 0.5)) {
                Fail ("data\ shrank to {0}% of the previous run ({1} MB -> {2} MB) — possible truncation." -f `
                    [math]::Round($dataBytes / $prevData * 100), [math]::Round($prevData/1MB,1), $dataMB)
            }
        }
    }
}

# --- Report ---
$healthy = ($problems.Count -eq 0)
$stamp   = Get-Date -Format 'yyyy-MM-dd HH:mm:ss'
Write-Host ''
if ($healthy) {
    Write-Host "PASS  Backup is healthy as of $stamp." -ForegroundColor Green
} else {
    Write-Host "FAIL  Backup health problems:" -ForegroundColor Red
    $problems | ForEach-Object { Write-Host "  - $_" -ForegroundColor Red }
}

# On-disk trail at the destination
try {
    $line = "$stamp  $(if($healthy){'PASS'}else{'FAIL'})  $(if($healthy){'healthy'}else{$problems -join ' | '})"
    Add-Content -LiteralPath (Join-Path $destRoot 'backup-check.log') -Value $line
} catch { Write-Warning "Could not write backup-check.log: $($_.Exception.Message)" }

# --- Dead-man's-switch heartbeat: ping ONLY on success ---
if ($heartbeat) {
    if ($healthy) {
        try {
            Invoke-WebRequest -Uri $heartbeat -UseBasicParsing -TimeoutSec 20 -Method Get | Out-Null
            Write-Host 'Heartbeat ping sent.' -ForegroundColor Green
        } catch {
            Write-Warning "Heartbeat ping failed: $($_.Exception.Message) (monitor will alarm on the missing check-in)."
        }
    } else {
        Write-Host 'Unhealthy — NOT pinging heartbeat. The external monitor should alert on the missing ping.' -ForegroundColor Yellow
        Write-Host '(healthchecks.io users: append /fail to the URL for an immediate alert.)'
    }
}

if (-not $healthy) { Write-Warning 'Investigate now — see od-backup-schedule.md triage.' }