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fix(continuum): singleton-guard auto-save, drop Start-Job #13

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fix(continuum): singleton-guard auto-save, drop Start-Job #13

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5 changes: 3 additions & 2 deletions psmux-continuum/plugin.conf
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Original file line number Diff line number Diff line change
Expand Up @@ -7,8 +7,9 @@
#
# NOTE: The auto_save.ps1 script runs a persistent loop (sleeping between
# saves). run-shell executes it asynchronously so it won't block psmux.
# If you attach multiple clients, multiple loops may start — this is
# harmless since saves are idempotent.
# It enforces a per-user singleton via PID file at
# %LOCALAPPDATA%\psmux-continuum\auto_save.pid, so re-firing this hook on
# every client attach will NOT spawn additional loops.

# Start auto-save background loop on client attach (every 15 minutes)
set-hook -g client-attached 'run-shell "pwsh -NoProfile -File \"~/.psmux/plugins/psmux-continuum/scripts/auto_save.ps1\" -IntervalMinutes 15"'
Expand Down
120 changes: 101 additions & 19 deletions psmux-continuum/psmux-continuum.ps1
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Original file line number Diff line number Diff line change
Expand Up @@ -33,8 +33,14 @@ if (-not (Test-Path $SCRIPTS_DIR)) {
}

# --- Create the auto-save background script ---
# NOTE: The auto_save loop is a per-user singleton enforced by a PID file
# at $env:LOCALAPPDATA\psmux-continuum\auto_save.pid. This means the
# client-attached hook in plugin.conf can re-fire on every re-attach
# without accumulating long-running pwsh processes — duplicate launches
# detect the live owner and exit immediately.
$autoSaveScript = @'
#!/usr/bin/env pwsh
# DO NOT EDIT — regenerated from psmux-continuum.ps1 on plugin load.
# psmux-continuum: Background auto-save loop
param(
[int]$IntervalMinutes = 15
Expand All @@ -50,6 +56,45 @@ function Get-PsmuxBin {
return 'psmux'
}

# --- Singleton guard: one auto-save loop per user ---
$pidDir = Join-Path $env:LOCALAPPDATA 'psmux-continuum'
$pidFile = Join-Path $pidDir 'auto_save.pid'
$logFile = Join-Path $pidDir 'auto_save.log'
New-Item -ItemType Directory -Path $pidDir -Force -ErrorAction SilentlyContinue | Out-Null

# Rotate the log if it grew past 256 KB. Add-Content reopens per write, so
# concurrent invocations don't corrupt each other's writes.
if ((Test-Path $logFile) -and ((Get-Item $logFile).Length -gt 262144)) {
Move-Item $logFile "$logFile.old" -Force -ErrorAction SilentlyContinue
}

function Log {
param([string]$Message, [string]$Level = 'INF')
try {
"[{0}] [{1}] [PID {2}] {3}" -f (Get-Date -Format 'yyyy-MM-dd HH:mm:ss'), $Level, $PID, $Message |
Add-Content -Path $logFile -Encoding UTF8 -ErrorAction Stop
}
catch {}
}

# If a live owner already holds the PID file, defer.
$existingPid = $null
try {
$existingPid = (Get-Content $pidFile -Raw -ErrorAction Stop).Trim()
}
catch {}
if ($existingPid -match '^\d+$') {
$existing = Get-Process -Id ([int]$existingPid) -ErrorAction SilentlyContinue
if ($existing -and ($existing.ProcessName -in @('pwsh','powershell'))) {
Log "auto-save already running (PID $existingPid), exiting."
exit 0
}
}

# Claim the slot
"$PID" | Set-Content -Path $pidFile -Encoding UTF8 -Force
Comment on lines +80 to +95
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@tarikguney tarikguney May 15, 2026

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@CosminRadu Can you please review this comment from CoPilot?

Log "claimed singleton slot; interval=${IntervalMinutes}m"

$PSMUX = Get-PsmuxBin

# Find the resurrect save script
Expand All @@ -59,25 +104,59 @@ if (-not (Test-Path $saveScript)) {
}

if (-not (Test-Path $saveScript)) {
Write-Host "psmux-continuum: psmux-resurrect not found. Install it first." -ForegroundColor Red
Log "psmux-resurrect not found. Install it first." 'ERR'
Remove-Item $pidFile -Force -ErrorAction SilentlyContinue
exit 1
}

$IntervalSeconds = $IntervalMinutes * 60

while ($true) {
Start-Sleep -Seconds $IntervalSeconds

# Check if psmux server is still running
$sessions = & $PSMUX ls 2>&1 | Out-String
if ($LASTEXITCODE -ne 0) {
Write-Host "psmux-continuum: Server not running, stopping auto-save." -ForegroundColor Yellow
break
$iter = 0

try {
while ($true) {
Start-Sleep -Seconds $IntervalSeconds

# Graceful supersede: if the PID file no longer points to us, exit.
$owner = $null
try {
$owner = (Get-Content $pidFile -Raw -ErrorAction Stop).Trim()
}
catch {}
if ($owner -ne "$PID") {
Log "superseded, exiting."
break
}

# Check if psmux server is still running
$sessions = & $PSMUX ls 2>&1 | Out-String
if ($LASTEXITCODE -ne 0) {
Log "psmux server not running, stopping auto-save." 'WRN'
break
}

# Run the save; capture all streams (output, errors, warnings) into the log.
& pwsh -NoProfile -File $saveScript *>> $logFile
Log "auto-saved."

# Bound memory growth in this long-running loop
$iter++
if (($iter % 4) -eq 0) {
[GC]::Collect()
[GC]::WaitForPendingFinalizers()
[GC]::Collect()
}
}

# Run the save
& pwsh -NoProfile -File $saveScript
Write-Host "psmux-continuum: Auto-saved at $(Get-Date -Format 'HH:mm:ss')" -ForegroundColor DarkGray
}
finally {
Log "exiting; releasing singleton slot."
# Release singleton slot only if we still own it
try {
$owner = (Get-Content $pidFile -Raw -ErrorAction Stop).Trim()
if ($owner -eq "$PID") {
Remove-Item $pidFile -Force -ErrorAction SilentlyContinue
}
}
catch {}
}
'@

Expand All @@ -86,6 +165,7 @@ Set-Content -Path (Join-Path $SCRIPTS_DIR 'auto_save.ps1') -Value $autoSaveScrip
# --- Create the auto-restore script ---
$autoRestoreScript = @'
#!/usr/bin/env pwsh
# DO NOT EDIT — regenerated from psmux-continuum.ps1 on plugin load.
# psmux-continuum: Auto-restore on server start
$ErrorActionPreference = 'Continue'

Expand All @@ -107,6 +187,7 @@ Set-Content -Path (Join-Path $SCRIPTS_DIR 'auto_restore.ps1') -Value $autoRestor
# --- Create boot script ---
$bootScript = @'
#!/usr/bin/env pwsh
# DO NOT EDIT — regenerated from psmux-continuum.ps1 on plugin load.
# psmux-continuum: Register/unregister psmux auto-start on Windows login
param(
[switch]$Enable,
Expand Down Expand Up @@ -143,7 +224,7 @@ if ($Enable) {

Set-Content -Path (Join-Path $SCRIPTS_DIR 'boot.ps1') -Value $bootScript -Force

# --- Start auto-save background job ---
# --- Start auto-save background loop ---
$interval = 15 # Default 15 minutes

# Try to read interval from psmux options
Expand All @@ -154,10 +235,11 @@ if ($intervalOpt -match '^\d+$') {

if ($interval -gt 0) {
$autoSavePath = Join-Path $SCRIPTS_DIR 'auto_save.ps1'
Start-Job -ScriptBlock {
param($script, $interval)
& pwsh -NoProfile -File $script -IntervalMinutes $interval
} -ArgumentList $autoSavePath, $interval | Out-Null
# Detached, hidden pwsh — single process, not a Start-Job wrapper.
# The singleton guard inside auto_save.ps1 makes repeated launches safe.
Start-Process -FilePath 'pwsh' `
-ArgumentList @('-NoProfile','-File',$autoSavePath,'-IntervalMinutes',"$interval") `
-WindowStyle Hidden | Out-Null
}

# --- Auto-restore on first load ---
Expand Down
1 change: 1 addition & 0 deletions psmux-continuum/scripts/auto_restore.ps1
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
#!/usr/bin/env pwsh
# DO NOT EDIT — regenerated from psmux-continuum.ps1 on plugin load.
# psmux-continuum: Auto-restore on server start
$ErrorActionPreference = 'Continue'

Expand Down
98 changes: 86 additions & 12 deletions psmux-continuum/scripts/auto_save.ps1
View file
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
#!/usr/bin/env pwsh
# DO NOT EDIT — regenerated from psmux-continuum.ps1 on plugin load.
# psmux-continuum: Background auto-save loop
param(
[int]$IntervalMinutes = 15
Expand All @@ -14,6 +15,45 @@ function Get-PsmuxBin {
return 'psmux'
}

# --- Singleton guard: one auto-save loop per user ---
$pidDir = Join-Path $env:LOCALAPPDATA 'psmux-continuum'
$pidFile = Join-Path $pidDir 'auto_save.pid'
$logFile = Join-Path $pidDir 'auto_save.log'
New-Item -ItemType Directory -Path $pidDir -Force -ErrorAction SilentlyContinue | Out-Null

# Rotate the log if it grew past 256 KB. Add-Content reopens per write, so
# concurrent invocations don't corrupt each other's writes.
if ((Test-Path $logFile) -and ((Get-Item $logFile).Length -gt 262144)) {
Move-Item $logFile "$logFile.old" -Force -ErrorAction SilentlyContinue
}

function Log {
param([string]$Message, [string]$Level = 'INF')
try {
"[{0}] [{1}] [PID {2}] {3}" -f (Get-Date -Format 'yyyy-MM-dd HH:mm:ss'), $Level, $PID, $Message |
Add-Content -Path $logFile -Encoding UTF8 -ErrorAction Stop
}
catch {}
}

# If a live owner already holds the PID file, defer.
$existingPid = $null
try {
$existingPid = (Get-Content $pidFile -Raw -ErrorAction Stop).Trim()
}
catch {}
if ($existingPid -match '^\d+$') {
$existing = Get-Process -Id ([int]$existingPid) -ErrorAction SilentlyContinue
if ($existing -and ($existing.ProcessName -in @('pwsh','powershell'))) {
Log "auto-save already running (PID $existingPid), exiting."
exit 0
}
}

# Claim the slot
"$PID" | Set-Content -Path $pidFile -Encoding UTF8 -Force
Log "claimed singleton slot; interval=${IntervalMinutes}m"

$PSMUX = Get-PsmuxBin

# Find the resurrect save script
Expand All @@ -23,23 +63,57 @@ if (-not (Test-Path $saveScript)) {
}

if (-not (Test-Path $saveScript)) {
Write-Host "psmux-continuum: psmux-resurrect not found. Install it first." -ForegroundColor Red
Log "psmux-resurrect not found. Install it first." 'ERR'
Remove-Item $pidFile -Force -ErrorAction SilentlyContinue
exit 1
}

$IntervalSeconds = $IntervalMinutes * 60
$iter = 0

while ($true) {
Start-Sleep -Seconds $IntervalSeconds
try {
while ($true) {
Start-Sleep -Seconds $IntervalSeconds

# Check if psmux server is still running
$sessions = & $PSMUX ls 2>&1 | Out-String
if ($LASTEXITCODE -ne 0) {
Write-Host "psmux-continuum: Server not running, stopping auto-save." -ForegroundColor Yellow
break
}
# Graceful supersede: if the PID file no longer points to us, exit.
$owner = $null
try {
$owner = (Get-Content $pidFile -Raw -ErrorAction Stop).Trim()
}
catch {}
if ($owner -ne "$PID") {
Log "superseded, exiting."
break
}

# Check if psmux server is still running
$sessions = & $PSMUX ls 2>&1 | Out-String
if ($LASTEXITCODE -ne 0) {
Log "psmux server not running, stopping auto-save." 'WRN'
break
}

# Run the save
& pwsh -NoProfile -File $saveScript
Write-Host "psmux-continuum: Auto-saved at $(Get-Date -Format 'HH:mm:ss')" -ForegroundColor DarkGray
# Run the save; capture all streams (output, errors, warnings) into the log.
& pwsh -NoProfile -File $saveScript *>> $logFile
Log "auto-saved."

# Bound memory growth in this long-running loop
$iter++
if (($iter % 4) -eq 0) {
[GC]::Collect()
[GC]::WaitForPendingFinalizers()
[GC]::Collect()
}
}
}
finally {
Log "exiting; releasing singleton slot."
# Release singleton slot only if we still own it
try {
$owner = (Get-Content $pidFile -Raw -ErrorAction Stop).Trim()
if ($owner -eq "$PID") {
Remove-Item $pidFile -Force -ErrorAction SilentlyContinue
}
}
catch {}
}
1 change: 1 addition & 0 deletions psmux-continuum/scripts/boot.ps1
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
#!/usr/bin/env pwsh
# DO NOT EDIT — regenerated from psmux-continuum.ps1 on plugin load.
# psmux-continuum: Register/unregister psmux auto-start on Windows login
param(
[switch]$Enable,
Expand Down