iptvnator/docs/development/electron-debugging.md

Electron debugging and tracing

Use this procedure for Electron/CDP tasks. Read the available electron skill when automating the desktop app. These commands assume a bootstrapped worktree.

Start and attach

• Start the Electron development app with: pnpm nx serve electron-backend
• Package-script equivalent: pnpm run serve:backend
• Electron is configured to start with: --remote-debugging-port=9222
• Connect Chrome DevTools Protocol tools to: 127.0.0.1:9222
• For Electron automation/debugging tasks, use the electron skill
• Do not auto-open DevTools during normal CDP automation. In development, DevTools is opt-in via ELECTRON_OPEN_DEVTOOLS=1.
• If DevTools is open, agent-browser --cdp 9222 ... may attach to the DevTools page instead of the IPTVnator window. Symptoms: tab list shows about:blank, snapshots are empty, and screenshots are black.
• If that happens, inspect targets with curl http://127.0.0.1:9222/json/list and connect directly to the IPTVnator page websocket from the webSocketDebuggerUrl field.
• The app holds a single-instance lock (acquireSingleInstanceLock in apps/electron-backend/src/app/services/single-instance.ts): a second launch against the same userData quits immediately and focuses the running window. To attach a second CDP-enabled instance to the same profile, set IPTVNATOR_ALLOW_MULTIPLE_INSTANCES=1 — knowing that only one of the two processes will own the renderer's IndexedDB, so settings written by the other are lost. Before focusing, the guard forwards the second launch's argv to onSecondInstance, which is how a playlist path handed to an already-running app reaches the open queue.

Trace / Debug Startup

• Full startup tracing:

IPTVNATOR_TRACE_STARTUP=1 pnpm nx serve electron-backend

• Narrower trace flags:

  • IPTVNATOR_TRACE_IPC=1 traces renderer window.electron.* bridge calls
  • IPTVNATOR_TRACE_DB=1 traces DB worker requests and request-scoped DB events
  • IPTVNATOR_TRACE_SQL=1 traces SQLite statements in the main process and DB worker
  • IPTVNATOR_TRACE_WINDOW=1 traces BrowserWindow lifecycle and unresponsive events
  • IPTVNATOR_TRACE_PLAYER=1 traces external-player activity and bounded Embedded MPV runtime-probe stderr
  • IPTVNATOR_TRACE_RENDERER_CONSOLE=1 mirrors renderer console output into the Electron terminal
  • IPTVNATOR_PERF_CAPTURE=1 enables development/test-only, redacted M3U and Xtream preload IPC request/completion markers plus count-only M3U acquire/parse/normalize, Xtream main network/JSON-transform/success-response-ready/cancel-dispatch, and renderer store phase capture; renderer wrappers emit only while the benchmark installs its Symbol hook, benchmark tooling sets the flag explicitly, and production launches must leave it unset
  • IPTVNATOR_PERF_WORKER_PROFILING=1 enables development/test-only, request-scoped worker receive/work/response-post timestamps, thread CPU, event-loop utilization/delay, count-only playlist serialization/SQLite write/read/deserialization plus Xtream category/content/cache-clear/delete/in-source-search phase events, profiling-only worker cancel-receipt acknowledgements, valid-sample-counted isolate peak memory, and the database worker's idle-only one-shot post-GC heap probe; overlapping database requests are explicitly invalidated instead of misattributed, the performance benchmark sets the flag automatically, and production launches must leave it unset

• Settings, portal request/response, and trace payloads must use @iptvnator/shared/logging or the redacting portal logger before reaching console.*; never log raw credentials while debugging.

• If local Nx state gets weird before a rerun:

pnpm nx reset

agent-browser (global install)

agent-browser --cdp 9222 tab list
agent-browser --cdp 9222 tab 1
agent-browser --cdp 9222 snapshot -i -c -d 4
agent-browser --cdp 9222 screenshot /tmp/iptvnator-cdp.png

Fallback

npx --yes agent-browser --cdp 9222 tab list

DevTools Workaround

ELECTRON_OPEN_DEVTOOLS=1 pnpm nx serve electron-backend
curl http://127.0.0.1:9222/json/list
agent-browser connect ws://127.0.0.1:9222/devtools/page/<iptvnator-page-id>
agent-browser screenshot /tmp/iptvnator-cdp.png

E2E process cleanup and packaged diagnostics

Playwright launches Electron through cmd.exe on Windows. If graceful E2E shutdown times out, terminate that process tree with taskkill /T /F; killing only electronApp.process() can leave Electron holding the temporary profile and make the next launch exit on the single-instance lock. The E2E workflow checks this against a real Windows shell and child process. Test cleanup must target only its own launch PID, never all Electron or IPTVnator processes. Cleanup confirms process exit even if Playwright's close promise fails or never settles. If termination fails, it retries and then throws instead of allowing a relaunch against a potentially locked profile. Capture the Node child-process handle immediately after launch and retain it for cleanup and preparation failures. After the last window closes on Linux, Electron can exit before cleanup begins; Playwright disposes its dispatcher, so calling electronApp.process() at that point can throw even after a clean exit. The retained handle still provides the actual exit code and signal.

The Linux portable build uploads packaged-frame-copy-smoke reports and traces even when the smoke fails. Check the paused-frame screenshot and trace before classifying a zero rendered-frame signal as an infrastructure flake.

Main-process ownership

The entry point is apps/electron-backend/src/main.ts; it bootstraps the database, registers events and creates the main window. The preload is apps/electron-backend/src/app/api/main.preload.ts, with handlers under apps/electron-backend/src/app/events/. The window follows the saved startup mode (normal/maximized/fullscreen); --fullscreen overrides a single launch. Use workspace shell for window behavior, DB worker for worker ownership and Electron security for bridge boundaries.