Concurrent Electron Instances (Multi-Instance Automation)

Status: implemented + empirically validated 2026-07-01. Multiple isolated dev Electron instances run concurrently, each with its own userData dir, Vite dev port, and IPC socket, each signed in from a copied login state, with independent renderer state. Three env-gated product knobs (LOBE_DESKTOP_USER_DATA_DIR, LOBE_IPC_ID, LOBE_DESKTOP_VITE_PORT) plus an electron-dev.sh instance pool. Details, collision matrix, and two validation transcripts below.

Use case driving this: N git worktrees under one project, each doing different work, each running its own Electron dev instance — so each needs its own Vite dev server + its own userData, while reusing the developer's existing login.

Worktree instance prerequisites (deps + first mount) — validated 2026-07-04

A git worktree starts with no node_modules (gitignored, not shared). Two traps sink an electron-dev.sh start <id> on a fresh worktree before it will even mount:

• pnpm install per worktree — do NOT symlink the main checkout's node_modules. Symlinking the primary repo's node_modules into the worktree looks like it works but silently pins the main branch's dependency versions, which can lag the worktree branch. Real failure: a worktree on canary imports FloatingPanel from @lobehub/ui ^5.19.0, but the symlinked main checkout had 5.18.0 → the renderer crashed at load (Uncaught SyntaxError: … does not provide an export named 'FloatingPanel') and the app hung on the loading screen (#root empty, __LOBE_STORES undefined) even though raw-CDP screenshots still showed a painted frame from before the crash. Fix: real pnpm install in the worktree root and apps/desktop (standalone install, per Step 0.1) before start. (type-check warns of the same skew: cross-root packages/* dual-identity errors when node_modules is symlinked across worktree roots.)
• First cold Vite load can ECONNRESET under resource contention. Two full Electron+Vite dev stacks at once (main app + a fresh worktree instance) can overwhelm Vite on the cold module storm: the log fills with Vite dev server fetch failed: http://127.0.0.1:<port>/src/… [read ECONNRESET], the SPA hangs on the loading screen, #root stays at 0 children. Not a code error — a clean electron-dev.sh stop <id> && start <id> once the install/CPU storm is over mounts cleanly (0 ECONNRESET, __LOBE_STORES becomes an object, #root fills).

"Screenshot shows the app but eval sees an empty #root" → the app never mounted (loading-screen shell), not a target mismatch. Confirm with eval "document.getElementById('root')?.childElementCount" (0 + a #loading-screen = not mounted). And remember cdp-screenshot.sh reads --port, not a CDP_PORT env — pass --port 92xx for a pool instance or you'll silently shoot the default 9222 (the main app), not your worktree instance.

The real bottleneck is NOT "one port"

CDP is single-port, multi-target: one --remote-debugging-port exposes every BrowserWindow as a target. What actually blocks N independent, write-isolated app sessions are dev-build singletons. Validated verdicts:

The key tension (and its resolution)

Two requirements pull opposite ways:

• Login-state reuse needs the app name constant — safeStorage (OIDC tokens in lobehub-settings.json) and Chromium cookie encryption (better-auth session in Cookies) derive their key from an OS-keychain entry named after the app. Change the app name → copied secrets no longer decrypt.
• IPC-socket uniqueness wants a per-instance appId (the socket path is os.tmpdir()/${appId}-electron-ipc.sock, appId = app name).

Naively "give each instance a different app name" (a tempting first instinct) breaks login reuse — the exact thing this use case needs. Resolution:

Keep app.setName('lobehub-desktop-dev') constant for every instance. Vary only the userData dir. That satisfies the single-instance lock (keyed by userData) AND keeps the keychain key valid so copied tokens/cookies decrypt. The IPC socket is decoupled from the app name via its own LOBE_IPC_ID knob (not the app name), so each instance still gets a distinct socket.

Product changes (all env-gated, all validated)

Three tiny env-gated knobs — no behavior change unless the env is set. This branch ships all three:

1. apps/desktop/src/main/pre-app-init.ts — per-instance userData, app name fixed (so copied login state still decrypts):

   tsCopy

   app.setName('lobehub-desktop-dev');
   const userDataOverride = process.env.LOBE_DESKTOP_USER_DATA_DIR;
   app.setPath(
     'userData',
     userDataOverride || path.join(app.getPath('appData'), 'lobehub-desktop-dev'),
   );
   

2. apps/desktop/src/main/core/App.ts — per-instance IPC id so the electron-server-ipc socket path stops colliding (no more "last one wins"):

   tsCopy

   const ipcId = process.env.LOBE_IPC_ID || name;
   this.ipcServer = new ElectronIPCServer(ipcId, ipcServerEvents);
   

3. apps/desktop/electron.vite.config.ts — per-instance Vite dev port (Model B: one Vite per worktree), kept strictPort so HMR clientPort matches:

   tsCopy

   const DEV_VITE_PORT = Number(process.env.LOBE_DESKTOP_VITE_PORT) || 5173;
   // ...used for both server.port and server.hmr.clientPort
   

All three verified live via the electron-dev.sh pool (transcript below).

Login-state reuse across userData dirs (validated)

To make a fresh userData dir come up already logged in, copy from the golden profile (~/Library/Application Support/lobehub-desktop-dev/) — only the login-bearing items, NOT the multi-GB caches:

SRC="$HOME/Library/Application Support/lobehub-desktop-dev"
DST="/tmp/lobe-ud-<id>"
for f in lobehub-settings.json "Local State" Preferences \
  Cookies Cookies-journal "Local Storage" IndexedDB \
  "Session Storage" "Network Persistent State" lobehub-storage; do
  [ -e "$SRC/$f" ] && cp -R "$SRC/$f" "$DST/"
done # ~27 MB vs the 1.7 GB full profile (Cache/Code Cache/GPUCache skipped)

• lobehub-settings.json → encryptedTokens (OIDC access/refresh, safeStorage).
• Cookies + Local Storage + IndexedDB → better-auth renderer session.
• Decryption works because app name is unchanged on the same machine (keychain entry lobehub-desktop-dev Safe Storage is reused). Same machine only — a copy to another machine won't decrypt.
• Stale-token caveat: if the copied access token's exp has passed you'll see Authentication failed: "exp" claim timestamp check failed — this actually confirms decryption succeeded (the token was decrypted, then found expired). isSignedIn still returns true (session/refresh recovers), but profile API calls may lag until refresh completes (the settings page briefly shows "Anonymous User" + skeletons). Copy from a freshly-active profile for a clean first paint.

IPC socket caveat (the one real conflict)

ipcServer.ts constructor does if (fs.existsSync(socketPath)) fs.unlinkSync(...) then binds. So starting instance N unlinks instance N-1's socket and takes over the path + rewrites ${appId}-electron-ipc-info.json. Observed: non-fatal, no crash, all instances keep running and their renderer↔main IPC (standard Electron ipcMain/ipcRenderer) is unaffected (that's per-webContents). Only the external electron-server-ipc channel — used by the embedded CLI lh and the Next server to reach the main process — resolves to the last-started instance. For CDP-driven UI automation this is harmless. To make it clean for a real feature, give the IPC server a per-instance appId (env, decoupled from app.setName) at App.ts where new ElectronIPCServer(appId, …) is constructed.

agent-browser driving gotcha (important)

The agent-browser daemon reuses one session across --cdp ports — calling agent-browser --cdp 9223 … then --cdp 9224 … both hit whichever target the daemon connected to first, so reads/writes bleed and look like cross-instance state sync (they aren't). Two correct patterns:

# ✅ pin a distinct session name per instance — supports concurrent driving
agent-browser --session s9223 --cdp 9223 snapshot -i
agent-browser --session s9224 --cdp 9224 snapshot -i

# ✅ or reset between targets (slower, serial)
agent-browser close --all && agent-browser --cdp 9223 get url

Raw curl http://localhost:<port>/json/list always shows a port's true target (title/url/id) and is the tie-breaker when in doubt.

Two operating models

Model A — one Vite, many electron processes (what the validation used)

One electron-vite dev owns Vite 5173 + the built dist/main; extra instances are raw electrons sharing the renderer via ELECTRON_RENDERER_URL:

# instance 1: owns Vite 5173 + is itself CDP 9223
cd apps/desktop
LOBE_DESKTOP_USER_DATA_DIR=/tmp/lobe-ud-1 \
  npx electron-vite dev -- --remote-debugging-port=9223

# instances 2,3: reuse Vite 5173 + built main, isolate userData + CDP
LOBE_DESKTOP_USER_DATA_DIR=/tmp/lobe-ud-2 ELECTRON_RENDERER_URL=http://127.0.0.1:5173 \
  npx electron . --remote-debugging-port=9224
LOBE_DESKTOP_USER_DATA_DIR=/tmp/lobe-ud-3 ELECTRON_RENDERER_URL=http://127.0.0.1:5173 \
  npx electron . --remote-debugging-port=9225

Lightest; all share one build/renderer. Extra instances get no HMR re-launch.

Model B — one Vite per worktree (the N-worktree use case)

Each worktree runs its own electron-vite dev (own code, own build, own HMR). The LOBE_DESKTOP_VITE_PORT knob makes this work — otherwise the 2nd worktree fails on strictPort 5173. Just use the pool (below), or by hand per worktree:

LOBE_DESKTOP_VITE_PORT=51xx LOBE_DESKTOP_USER_DATA_DIR=… LOBE_IPC_ID=… \
  npx electron-vite dev -- --remote-debugging-port=92xx

electron-vite dev injects the matching ELECTRON_RENDERER_URL automatically. Cost: N Vite servers + N builds (heavy); acceptable since each worktree is a distinct dev target. Validated — two electron-vite dev on 5174 + 5175 ran concurrently (transcript below).

electron-dev.sh instance pool (implemented)

scripts/electron-dev.sh now keys lifecycle on an instance id, not the project path (the old single-instance script matched every project Electron by binary path, so a 2nd start tore down the 1st):

electron-dev.sh start 1    # CDP 9223, Vite 5174, userData ud-1 (login copied), IPC id -1
electron-dev.sh start 2    # CDP 9224, Vite 5175, userData ud-2, IPC id -2
electron-dev.sh list       # show running pool instances
electron-dev.sh stop 1     # sibling-safe: kills ONLY instance 1 (KEEP_DATA=1 to keep ud)
electron-dev.sh stop --all # stop every instance
# no id → legacy single-instance behavior (CDP 9222), unchanged

• Derives CDP=9222+id, Vite=5173+id, userData=$POOL_DIR/ud-<id>, IPC id=lobehub-desktop-dev-<id>, per-id log + pidfile.
• start <id> seeds a fresh userData with the login-item set from the golden profile (override via LOBE_GOLDEN_PROFILE); stop <id> wipes it unless KEEP_DATA=1.
• stop <id> matches by pidfile session-leader tree + CDP/Vite port holders, never the broad project path → never kills a sibling.
• Drive each instance with agent-browser --session s<port> --cdp <port>.

Validation transcripts (2026-07-01)

Round 1 — concurrency, login reuse, isolation (Model A)

Golden profile lobehub-desktop-dev (logged in, user_2gmT…); 3 userData copies (27 MB each), app name constant. inst1 = electron-vite dev (CDP 9223, Vite 5173), inst2/inst3 = raw electron (CDP 9224/9225) sharing Vite.

• ✅ All 3 booted — no single-instance exit (distinct SingletonLock PIDs).
• ✅ All 3 signed in — isSignedIn:true, user_2gmT… on all ports (copied safeStorage tokens decrypted; app name unchanged).
• ✅ State isolated — raw /json/list showed distinct target ids + URLs. The "all same route" seen mid-test was the agent-browser daemon session-reuse artifact, fixed by per-instance --session.
• ⚠️ IPC socket hijack (pre-fix) — last-started instance owned the socket; non-fatal, renderers unaffected. → motivated the LOBE_IPC_ID fix below.

Round 2 — the three product knobs + the pool (Model B)

electron-dev.sh start 1 + start 2 on the fixed build:

• ✅ Vite port override — 5174 and 5175 bound concurrently (two electron-vite dev, strictPort no longer collides).
• ✅ IPC decouple — two distinct sockets lobehub-desktop-dev-1-…sock + …-2-…sock; no hijack.
• ✅ userData isolation — ud-1 / ud-2 with distinct SingletonLock PIDs; both CDP ports reachable; list shows both UP.
• ✅ Sibling-safe stop — stop 1 killed instance 1's 7-proc tree + wiped ud-1, while instance 2 (9224 / 5175 / its socket) stayed fully alive.

Teardown: stop --all; rm -rf pool dir. Ports released.