Sync: Add pause/unpause functionality for sync uploads #2379

gavande1 · 2026-01-12T11:35:32Z

Related issues

Fixes STU-1143

Proposed Changes

Add pause/resume buttons for TUS uploads during sync
Add manual pause state separate from network pause
Rename sync-upload-paused to sync-upload-network-paused for clarity
Add pause/play icon components
Update UI to show info icon with tooltip when manually paused

Testing Instructions

Checkout this branch
Run npm start
Connect a site to sync if not already connected
Start a sync push operation
Click pause button during upload phase
Verify upload pauses and shows resume button
Click resume to continue upload
Verify upload resumes from where it left off

CleanShot.2026-01-12.at.17.02.49.mp4

wpmobilebot · 2026-01-12T11:52:59Z

📊 Performance Test Results

Comparing 9be6d83 vs trunk

site-editor

Metric	trunk	`9be6d83`	Diff	Change
load	7587.00 ms	5657.00 ms	-1930.00 ms	🟢 -25.4%

site-startup

Metric	trunk	`9be6d83`	Diff	Change
siteCreation	9097.00 ms	16089.00 ms	+6992.00 ms	🔴 76.9%
siteStartup	3960.00 ms	3952.00 ms	-8.00 ms	🟢 -0.2%

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change

ivan-ottinger

This a great! Thanks for adding the Pause/Play button to the sync process, Rahul.

The changes look good to me and they work as expected. 👍🏼

I left couple comments on things I noticed.

When clicking the Play/Pause button, the progress jumps a bit. Maybe we could consider adjusting the logic to prevent that behavior.

src/components/icons/pause.tsx

src/components/icons/play.tsx

ivan-ottinger · 2026-01-13T15:04:23Z

Actually, I noticed one issue: Sometimes, when pausing and resuming the upload, the operation fails with the following error:

[2026-01-13T15:02:32.232Z][info][main] Database export saved to /var/folders/p1/f6m7sk7948g6zj6plt84p13m0000gn/T/studio_exportUyHKOg
[2026-01-13T15:02:38.132Z][info][main] Backup created at: /var/folders/p1/f6m7sk7948g6zj6plt84p13m0000gn/T/com.wordpress.studio/site_ff7be311-4557-4a5d-bfff-99b997aee54c.tar.gz
[2026-01-13T15:02:40.655Z][erro][main] Error occurred in handler for 'pushArchive': Error: Upload completed but required header not found
    at Object.onSuccess (/Users/ivanottinger/a8c/studio/dist/main/index.js:6468:18)
    at Upload._emitSuccess (/Users/ivanottinger/a8c/studio/node_modules/tus-js-client/lib.es5/upload.js:989:22)
    at /Users/ivanottinger/a8c/studio/node_modules/tus-js-client/lib.es5/upload.js:1158:20
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)

katinthehatsite · 2026-01-13T15:15:27Z

I got the same error as Ivan:

Error occurred in handler for 'pushArchive': Error: Upload completed but required header not found
at Object.onSuccess (/Users/katerynakodonenko/Documents/A8C-Projects/studio/studio/dist/main/index.js:6468:18)
at Upload._emitSuccess (/Users/katerynakodonenko/Documents/A8C-Projects/studio/studio/node_modules/tus-js-client/lib.es5/upload.js:989:22)
at /Users/katerynakodonenko/Documents/A8C-Projects/studio/studio/node_modules/tus-js-client/lib.es5/upload.js:1158:20
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
Sentry Logger [log]: Captured error event Error invoking remote method 'pushArchive': Error: Upload completed but required header not found

src/modules/sync/components/sync-connected-sites.tsx

katinthehatsite

Thanks for adding these changes, this will be a great improvement for the users!

I found one edge case where I seem to be getting errors:

Start push process on a site
Pause an upload
Cancel the upload
Start again the push process for the same site
Wait until the upload can be paused
Pause the upload
Observe that this throws an error:

This is the details that are captured to Sentry:

Sentry Logger [log]: Captured error event `Error invoking remote method 'pushArchive': reply was never sent`

gavande1 · 2026-01-14T17:22:58Z

Thanks @ivan-ottinger and @katinthehatsite for noticing this error and reporting them. I have fixed the issue with the cancel push operation. It should also fix the issues you reported earlier. It would great if you could give another review. 🙂

katinthehatsite · 2026-01-14T19:00:31Z

Thanks @ivan-ottinger and @katinthehatsite for noticing this error and reporting them. I have fixed the issue with the cancel push operation. It should also fix the issues you reported earlier. It would great if you could give another review. 🙂

Nice, I am not seeing these errors anymore 👍 Functionality-wise, everything looked good to me. I will review the code a bit closer tomorrow morning with fresh eyes

src/modules/sync/lib/ipc-handlers.ts

ivan-ottinger · 2026-01-15T09:27:25Z

Thanks @ivan-ottinger and @katinthehatsite for noticing this error and reporting them. I have fixed the issue with the cancel push operation. It should also fix the issues you reported earlier. It would great if you could give another review. 🙂

Thank you for the updates, Rahul. I am still getting error when pausing and resuming, but different one this time:

Database export saved to /var/folders/p1/f6m7sk7948g6zj6plt84p13m0000gn/T/studio_exportw5IZUQ
Backup created at: /var/folders/p1/f6m7sk7948g6zj6plt84p13m0000gn/T/com.wordpress.studio/site_fdf6ffd0-6b85-4a3e-82ec-20e6d70b250e.tar.gz
Database export saved to /var/folders/p1/f6m7sk7948g6zj6plt84p13m0000gn/T/studio_export6HODEZ
Backup created at: /var/folders/p1/f6m7sk7948g6zj6plt84p13m0000gn/T/com.wordpress.studio/site_fdf6ffd0-6b85-4a3e-82ec-20e6d70b250e.tar.gz
Sentry Logger [log]: Captured error event `Object captured as exception with keys: error, success`
Sentry Logger [error]: Transport disabled

src/modules/sync/lib/ipc-handlers.ts

katinthehatsite

It is looking good overall on my end, I left some minor comments for consideration.

wojtekn · 2026-01-15T11:02:33Z

Feature-wise looks good, but I think we should adjust the design before we merge:

icons style doesn't match the X icon, as they are thicker
bar width and text position shouldn't change when icons appear

gavande1 · 2026-01-16T07:24:45Z

icons style doesn't match the X icon, as they are thicker
bar width and text position shouldn't change when icons appear

Thanks, Wojtek, for raising this. These were my concerns as well. I am waiting for a response from @Marinatsu on design feedback.

Edit: I have updated the pause icon to match style of X icon from WordPress icons. I added that in 9be6d83.

gavande1 · 2026-01-16T07:33:10Z

Thank you for the updates, Rahul. I am still getting error when pausing and resuming, but different one this time:

Database export saved to /var/folders/p1/f6m7sk7948g6zj6plt84p13m0000gn/T/studio_exportw5IZUQ
Backup created at: /var/folders/p1/f6m7sk7948g6zj6plt84p13m0000gn/T/com.wordpress.studio/site_fdf6ffd0-6b85-4a3e-82ec-20e6d70b250e.tar.gz
Database export saved to /var/folders/p1/f6m7sk7948g6zj6plt84p13m0000gn/T/studio_export6HODEZ
Backup created at: /var/folders/p1/f6m7sk7948g6zj6plt84p13m0000gn/T/com.wordpress.studio/site_fdf6ffd0-6b85-4a3e-82ec-20e6d70b250e.tar.gz
Sentry Logger [log]: Captured error event `Object captured as exception with keys: error, success`
Sentry Logger [error]: Transport disabled

Thanks @ivan-ottinger. I couldn't reproduce the error. But I tried to fix the issue in b6b2040. Can you give a quick test?

katinthehatsite

I found one more interesting case while testing:

Connect two sites to a Studio site
Start Push process on the connected site A and pause the upload
Start Push process on the connected site B
Unpause the uploads
Observe the Studio site pushing the changes to two sites at once:

I also noticed an error in Sentry for this case:

Backup created at: /var/folders/bj/1qgxs1qd6_z20tw9llkw842h0000gn/T/com.wordpress.studio/site_d354f946-9026-4a52-a2ff-cd3ac7c2d172.tar.gz
Backup created at: /var/folders/bj/1qgxs1qd6_z20tw9llkw842h0000gn/T/com.wordpress.studio/site_d354f946-9026-4a52-a2ff-cd3ac7c2d172.tar.gz
Sentry Logger [log]: Captured error event `ENOENT: no such file or directory, unlink '/var/folders/bj/1qgxs1qd6_z20tw9llkw842h0000gn/T/com.wordpress.studio/site_d354f946-9026-4a52-a2ff-cd3ac7c2d172.tar.gz'`

I know that we are currently blocking the UI for pushing and pulling more than to one site at a time so I am wondering if we might want to stay consistent here as well:

In terms of functinality, with this edge case, the push worked for one site and for the other one, it sort of got stuck and it is still pending for me. I will update this comment if it goes through but I think it is probably related to the error I saw in Sentry.

katinthehatsite · 2026-01-16T09:56:51Z

src/components/icons/pause.tsx

@@ -0,0 +1,6 @@
+export const PauseIcon = () => (
+	<svg width="24" height="24" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg">


I noticed that the sizing of the icons is different and I could see that difference visually, not a huge one. What do you think about making it consistent?

Fixed in 9892f91

ivan-ottinger · 2026-01-16T10:07:46Z

Thanks @ivan-ottinger. I couldn't reproduce the error. But I tried to fix the issue in b6b2040. Can you give a quick test?

I have run multiple tests and spotted that the issue happens only when we pause at 100% of the upload progress. Since by then the upload is finished, I think we can hide the Pause button at that point, which should resolve the issue.

CleanShot.2026-01-16.at.11.06.54.mp4

gavande1 · 2026-01-20T19:05:36Z

@ivan-ottinger Thanks for your suggestion. I have applied your suggestion in 2ec6e22.

ivan-ottinger

@ivan-ottinger Thanks for your suggestion. I have applied your suggestion in 2ec6e22.

Thanks for the update, Rahul! The change there looks good and I can confirm it fixes the issue. I did not observe any other edge cases and pausing / resuming works great. 👍🏼

I understand there might still be a design adjustment related to the buttons coming, but I am already approving the PR in case we would like to merge it in its current state.

Btw, I have tested on a rebased branch with latest trunk locally, just did not push it remotely.

gavande1 · 2026-01-21T12:35:25Z

I understand there might still be a design adjustment related to the buttons coming, but I am already approving the PR in case we would like to merge it in its current state.

Tbh, I am not happy with the layout shift it does when the Play/Pause button appears and hides. It definitely needs some better UX in IHMO. cc @Marinatsu 🙂

crisbusquets · 2026-01-22T17:18:01Z

Hi!

I reviewed the last video shared.

There are two moments where we have odd layout shifts:

The one @gavande1 described above.
When the icons disappear to make room for the "Error pushing changes".

I see two potential solutions:

Add an easy-in-out transition so everything looks smoother, and it's clear that it transitions from one state to the other
We can also define a fixed width for that, so it doesn't change its size when there's the X and then ▶️, or when it gets replaced with the Clear option when there's an error.

wojtekn · 2026-01-23T08:30:20Z

Thanks for looking into this @crisbusquets

We can also define a fixed width for that, so it doesn't change its size when there's the X and then ▶️, or when it gets replaced with the Clear option when there's an error.

I think this is the simplest path forward and would result in good UX without any animated or non-animated layout shifts.

gavande1 changed the title ~~Add pause/unpause functionality for sync uploads~~ Sync: Add pause/unpause functionality for sync uploads Jan 12, 2026

gavande1 self-assigned this Jan 12, 2026

gavande1 requested a review from a team January 12, 2026 11:44

ivan-ottinger reviewed Jan 13, 2026

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gavande1 force-pushed the stu-1143-pause-unpause-sync-uploads branch from fc6c530 to 6d93fa7 Compare January 14, 2026 17:11

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gavande1 added 7 commits January 20, 2026 22:07

Add pause and play icons for sync upload controls

54011fc

Add pause/resume IPC handlers for TUS uploads

0fd7a49

Add uploadingManuallyPaused state and update cancel logic

7963083

Add pause/resume upload hooks and expose in context

56baa4c

Add pause/resume UI controls for sync uploads

d24028e

Update tests to include pause/resume upload mocks

beb7875

Fix TUS upload cancellation to prevent reply never sent error

6cd11b2

gavande1 added 5 commits January 20, 2026 22:08

Fix tooltip position

6e779d7

Add error handling for aborted export in sync push hook

78b80c8

Abort existing TUS upload before starting a new one

5a0d878

Update PauseIcon component

11d2101

Refactor PauseIcon component to use a smaller size

9892f91

gavande1 force-pushed the stu-1143-pause-unpause-sync-uploads branch from 9be6d83 to 9892f91 Compare January 20, 2026 17:54

Update upload pause logic to conditionally

2ec6e22

Improve sync upload pause/resume logic to check manual pause state

f3c1926

ivan-ottinger self-requested a review January 21, 2026 09:07

ivan-ottinger approved these changes Jan 21, 2026

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		@@ -0,0 +1,6 @@
		export const PauseIcon = () => (
		<svg width="24" height="24" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg">

Sync: Add pause/unpause functionality for sync uploads #2379

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