feat: track response time of `invoke` and `sendSync` methods on `ipcRenderer` by hitarth-gg · Pull Request #275 · electron/devtron

hitarth-gg · 2025-07-31T11:58:37Z

Description of Change

Allows Devtron to track the time (in milliseconds) it takes for ipcRenderer.invoke and ipcRenderer.sendSync to receive responses back from the main process.
Patches .on, .off, .once, .addListener, .removeListener, .removeAllListeners, .handle, .handleOnce, and .removeHandler methods of ipcMain to allow Devtron to track response times and detect when handlers or listeners are removed from ipcMain.

Tracking `.sendSync` and `.invoke` response times:

Request	Response

Clicking on the Linked Event field in the Details Panel will redirect the user to the linked event.
Internally, the two events are linked using a UUID. Renderer process generates a UUID and includes it in the arguments of .sendSync and .invoke requests. This UUID is then received by the main process, where it is extracted from the arguments. As a result, both processes use the same UUID to track the events. Events with matching UUIDs are then linked together in the frontend.

Tracking `.once` and `.handleOnce`:

ipcMain.once is tracked as two separate events: ipcMain.removeListener and ipcMain.on.
ipcMain.handleOnce is tracked as two separate events: ipcMain.removeHandler and ipcMain.handle.

hitarth-gg · 2025-08-07T10:19:09Z

One thing that might confuse end users is that when ipcMain.once is used, it appears as if .removeListener is called before .on is registered. This happens because .on is tracked using session.defaultSession.on("-ipc-message", ...) which logs events after the patched ipcMain.removeListener is already done logging. Curious to hear what others think about this behavior.

src/types/shared.ts

src/lib/electron-renderer-tracker.ts

src/extension/react/components/Panel.tsx

samuelmaddock · 2025-08-07T14:37:33Z

src/index.ts

+    const cleanedListener = async (event: Electron.IpcMainInvokeEvent, ...args: any[]) => {
+      const newArgs = getArgsFromPayload(args);
+      const result = await listener(event, ...newArgs);
+      return result;


It could be interesting to track the result as well so it can be later inspected. Not blocking for this PR.

Added it to the GSoC issue. I can probably do it in a follow up PR.

yangannyx · 2025-08-07T15:15:20Z

src/index.ts

+  const getArgsFromPayload = (payload: any[]): any[] => {
+    if (payload[0] && typeof payload[0] === 'object' && payload[0].__uuid__devtron) {
+      // If the first argument is an object with __uuid__devtron, return its args property
+      return payload[0].args || [];
+    }
+    // Otherwise, return the payload as is
+    return payload;
+  };


nit: it would be nice if we could extend/reuse this helper function above in trackIpcEvent

Fixed: 18adb6d
Lmk if it still needs changes.

yangannyx · 2025-08-07T15:20:41Z

src/index.ts

 }

+function patchIpcMain() {
+  const listenerMap = new Map<string, Map<any, any>>(); // channel -> (originalListener -> tracked/cleaned Listener)


Appreciate the comment here!
nit: It might be nice to create named types to make this code more self documenting:

Suggested change

const listenerMap = new Map<string, Map<any, any>>(); // channel -> (originalListener -> tracked/cleaned Listener)

// top level

type Channel = string

type Listener = any

...

const listenerMap = new Map<Channel, Map<Listener, Listener>>(); // channel -> (originalListener -> tracked/cleaned Listener)

Fixed: 1f049bf

[non-blocking] Nice, though it looks like (event: Electron.IpcMainEvent, ...args: any[]) => void, might be a better type for Listener? The best way to make these named types useful is to use them across the file, so I'd also encourage you to update the typings of channel and listener beyond just listenerMap

[non-blocking] Similar to data, types benefit from having a single source of truth. It's a good idea to define types like this at the highest relevant level in the repo so that they can be reused across all files where the type is relevant. It might be good to declare the Channel type in src/types and use it in IpcEventData.channel. Since this file is the only (I think) that deals with listeners, it makes sense to just declare the listener type in this file for now

Tried fixing it here: 7d5813e
Batched some other type-safety related changes into this commit as well.

If anything isn’t up to the mark, I’ll be happy to make the necessary changes.

yangannyx · 2025-08-07T15:41:23Z

src/extension/react/components/Panel.tsx

+          const updated = [...prev, event].slice(-MAX_EVENTS_TO_DISPLAY);
+          // If the event with the same UUID already exists, we update it
+          if (event.uuid && uuidMapRef.current.has(event.uuid)) {
+            const index = uuidMapRef.current.get(event.uuid)!;
+            if (index < prev.length) {
+              // update the old event to include a link to the new event
+              const oldEvent = updated[index];
+              oldEvent.gotoSerialNumber = event.serialNumber;
+              updated[index] = oldEvent;
+              // add a link to the old event in the new event
+              updated[updated.length - 1] = { ...event, gotoSerialNumber: index + 1 };
+            }
+            uuidMapRef.current.delete(event.uuid);
+          } else if (event.uuid) {
+            // If a UUID is encountered for the first time, we store its index
+            uuidMapRef.current.set(event.uuid, updated.length - 1);


I think you'll run into a couple of issues when the events array is at MAX_EVENTS_TO_DISPLAY

uuidMapRef indices might be stale and point to shifted events

new entries to uuidMapRef will all have the same index value since updated.length is now constant

I switched to using serialNumber instead of indexes in f998f34 and updated the comments I had forgotten to change in 3616cf0.

hitarth-gg · 2025-08-08T22:10:02Z

Updated the NPM Package to 0.0.0-development.13, which includes all commits up to this point.

While testing the npm package with Electron Fiddle, I noticed that the line The service-worker for Devtron is not registered yet. Cannot track IPC event. is logged 10-20 times as the IPC events sent before Devtron's SW is initialized aren't captured. I'll likely add an option to hide logs by level in a future PR, or remove this log entirely.

yangannyx · 2025-08-11T18:55:16Z

src/extension/react/components/Panel.tsx

+type UUID = string;
+type SerialNumber = number;


[non-blocking] Move these up to the top-level shared types file to tie these types with the IPCEventData shape more explicitly

Suggested change

type UUID = string;

type SerialNumber = number;

// in src/types/shared.ts

export type UUID = string;

export type SerialNumber = number;

...

export interface IpcEventData {

....

uuid?: UUID,

}

...

export interface IpcEventDataIndexed extends IpcEventData {

serialNumber: SerialNumber;

gotoSerialNumber?: SerialNumber; // For navigating to a specific event in the grid

}

Fixed, this was batched in 7d5813e.

yangannyx · 2025-08-11T18:59:19Z

src/extension/react/components/Panel.tsx

          if (lockToBottomRef.current) {
            requestAnimationFrame(() => {
              requestAnimationFrame(() => {
-                gridRef.current?.api.ensureIndexVisible(updated.length - 1, 'bottom');
+                scrollToRow(updated.length - 1, 'bottom');


[non-blocking] Calling side-effects from within a React useState setter's callback is nonstandard. For requestAnimationFrame, consider using useLayoutEffect.

Fixed: 9656a9b

yangannyx

PR LGTM from a functionality standpoint! Left some nonblocking suggestions around better type reusability, but don't want to bike shed on it

hitarth-gg · 2025-08-19T12:50:43Z

Rebased onto the next branch and resolved merge conflicts in src/index.ts.

Note: This rebase rewrote commit hashes, so all commits show up as new. In reality, the only change since the last review is resolving merge conflicts in src/index.ts. No other files were modified.

Co-authored-by: Sam Maddock <samuel.maddock@gmail.com>

hitarth-gg · 2025-08-19T20:08:36Z

Rebased onto the next branch and resolved merge conflicts in src/index.ts.

Note: This rebase rewrote commit hashes, so all commits show up as new. In reality, the only change since the last review is resolving merge conflicts in src/index.ts. No other files were modified.

Rebased and fixed merge conflicts again.

hitarth-gg force-pushed the feat/track-response-time branch 2 times, most recently from c8f1372 to 7cb718d Compare July 31, 2025 12:14

hitarth-gg added the GSoC 2025 label Jul 31, 2025

hitarth-gg mentioned this pull request Jul 31, 2025

[GSoC] Devtron: Progress, Known Issues, and Next Steps #272

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hitarth-gg force-pushed the feat/track-response-time branch from 7cb718d to 22a4d7c Compare August 7, 2025 08:11

hitarth-gg marked this pull request as ready for review August 7, 2025 10:23

hitarth-gg force-pushed the feat/track-response-time branch from 22a4d7c to f47bca4 Compare August 7, 2025 14:35

samuelmaddock reviewed Aug 7, 2025

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yangannyx reviewed Aug 7, 2025

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hitarth-gg closed this Aug 8, 2025

hitarth-gg reopened this Aug 8, 2025

yangannyx reviewed Aug 11, 2025

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yangannyx approved these changes Aug 11, 2025

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samuelmaddock approved these changes Aug 14, 2025

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hitarth-gg force-pushed the feat/track-response-time branch from 9656a9b to c2fabdf Compare August 19, 2025 12:33

hitarth-gg and others added 11 commits August 20, 2025 01:31

feat: track ipcRenderer invoke/sendSync response time

0c1c91b

feat: link related events using UUID

5aea448

fix: remove uuid and node:perf_hooks to fix preload loading issue

032e1ed

chore: remove duplicate type entry

fa2888f

Co-authored-by: Sam Maddock <samuel.maddock@gmail.com>

chore: remove unused className

a063f20

Co-authored-by: Sam Maddock <samuel.maddock@gmail.com>

refactor: define Channel and Listener type aliases at top level

e50e2ea

refactor: add IPC payload helpers

adb9666

fix: handle stale uuidMapRef indices when event list is full

080235a

fix: prevent crash when service worker is undefined

aa81e25

fix: comments

1f18fe4

refactor: improve type safety

250ac7d

chore: move scroll logic to useLayoutEffect

22927f9

hitarth-gg force-pushed the feat/track-response-time branch from c2fabdf to 22927f9 Compare August 19, 2025 20:08

lint

07678bb

samuelmaddock merged commit f0a2941 into next Aug 21, 2025

dsanders11 deleted the feat/track-response-time branch August 21, 2025 20:44

-  const listenerMap = new Map<string, Map<any, any>>(); // channel -> (originalListener -> tracked/cleaned Listener)
+// top level
+type Channel = string
+type Listener = any
+...
+  const listenerMap = new Map<Channel, Map<Listener, Listener>>(); // channel -> (originalListener -> tracked/cleaned Listener)

-type UUID = string;
-type SerialNumber = number;
+// in src/types/shared.ts
+export type UUID = string;
+export type SerialNumber = number;
+...
+export interface IpcEventData {
+    ....
+    uuid?: UUID,
+}
+...
+export interface IpcEventDataIndexed extends IpcEventData {
+  serialNumber: SerialNumber;
+  gotoSerialNumber?: SerialNumber; // For navigating to a specific event in the grid
+}

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hitarth-gg commented Jul 31, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Description of Change

Tracking .sendSync and .invoke response times:

Tracking .once and .handleOnce:

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hitarth-gg commented Aug 7, 2025

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hitarth-gg commented Jul 31, 2025 •

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Tracking `.sendSync` and `.invoke` response times:

Tracking `.once` and `.handleOnce`:

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