Implements plan item A2. With IPTVNATOR_PERF_CAPTURE=1 the main process
keeps named counters and registers a main-only performance:read-counters
IPC handler; without the flag nothing is counted and the handler does not
exist.
- debug-trace.ts owns the registry; traceStartupPhase replaces the
trace('startup', ...) sites and counts main.startupPhases.
- The database worker counts executed statements through better-sqlite3's
Statement prototype (the verbose callback expands every statement and
made bulk inserts 2-4x slower) and posts the count over its message
port, flushed before every other worker message. The main-thread shared
connection is counted through a new connection observer in the shared
database library.
- The first main window freezes main.modulesRegisteredBeforeWindow at
creation and main.sqlStatementsBeforeReadyToShow at ready-to-show.
- The journey gate drops the ready-to-show that Electron emits for the
about:blank detour, so the app sees the real document's first paint,
and taps the counters handler; the J1 record reads both counters after
the renderer probe completes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
8.6 KiB
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
electronskill - 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 listshowsabout:blank, snapshots are empty, and screenshots are black. - If that happens, inspect targets with
curl http://127.0.0.1:9222/json/listand connect directly to the IPTVnator page websocket from thewebSocketDebuggerUrlfield. - The app holds a single-instance lock (
acquireSingleInstanceLockinapps/electron-backend/src/app/services/single-instance.ts): a second launch against the sameuserDataquits immediately and focuses the running window. To attach a second CDP-enabled instance to the same profile, setIPTVNATOR_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 toonSecondInstance, 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=1traces rendererwindow.electron.*bridge callsIPTVNATOR_TRACE_DB=1traces DB worker requests and request-scoped DB eventsIPTVNATOR_TRACE_SQL=1traces SQLite statements in the main process and DB workerIPTVNATOR_TRACE_WINDOW=1traces BrowserWindow lifecycle and unresponsive eventsIPTVNATOR_TRACE_PLAYER=1traces external-player activity and bounded Embedded MPV runtime-probe stderrIPTVNATOR_TRACE_RENDERER_CONSOLE=1mirrors renderer console output into the Electron terminalIPTVNATOR_PERF_CAPTURE=1enables 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. It also keeps count-only main-process counters (startup phases, database worker SQL statements, and their values at main-window creation andready-to-show) and registers the main-onlyperformance:read-countersIPC handler, which the preload does not expose; see performance journeysIPTVNATOR_PERF_WORKER_PROFILING=1enables 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 unsetIPTVNATOR_DISABLE_COMPILE_CACHE=1disables the main-process V8 compile cache;IPTVNATOR_COMPILE_CACHE_DIR=<dir>relocates it. The startup trace reports the outcome ascompile-cache
-
Settings, portal request/response, and trace payloads must use
@iptvnator/shared/loggingor the redacting portal logger before reachingconsole.*; 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
in a WeakMap keyed by the Electron application for cleanup and preparation
failures. This binding follows the application when restart callers replace
only the application/window fields on their fixture. 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.
The Snap and Flatpak --embedded-mpv-runtime-probe launches in
build-and-make.yaml run under GNU timeout --verbose -k 10 300 with
ELECTRON_ENABLE_LOGGING=1, so a main process that throws before app ready
and blocks on Electron's uncaught-exception dialog under xvfb fails within
five minutes with a distinct ::error:: (exit 124, or 137 after timeout's
announced KILL escalation) and its stderr in the step log, instead of holding
the job until the 120-minute limit.
Main-process ownership
The process entry is apps/electron-backend/src/main.entry.ts (built to
dist/apps/electron-backend/main.js): it enables the V8 compile cache under
userData/v8-compile-cache and then requires the application bundle,
main.app.js, built from apps/electron-backend/src/main.ts. Before the window
loads, main.ts registers only what the renderer can call before its first paint
(window state, the close guard, playlist-open requests, request-header shims);
everything else, including the database, portal, EPG, download, player,
remote-control and update IPC, lives in
apps/electron-backend/src/app/startup/deferred-events.ts, built as the
deferred-events.js chunk and loaded inside the window's did-start-loading
listener. That import and its registrations finish within the same task, so no
renderer invoke can find a missing handler (app/startup/deferred-bootstrap.ts
holds the scheduler and its test); the startup trace reports it as
deferred-events:start and deferred-events:done. The cache is
disposable; IPTVNATOR_DISABLE_COMPILE_CACHE=1 turns it off and
IPTVNATOR_COMPILE_CACHE_DIR relocates it (E2E runs keep it inside
IPTVNATOR_E2E_DATA_DIR). nx-electron packages the backend through an
allowlist, so apps/electron-backend/project.json lists main.app.js and
deferred-events.js under the files option of the package and make
targets, and verify:package-layout fails when any of the entry files is missing
from app.asar. 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.