Do not restart FTL while `pihole -g` is still ongoing #2419

DL6ER · 2025-04-06T18:11:49Z

What does this implement/fix?

Do not try to restart FTL when a streamed pihole -g run is still ongoing. This to prevent being stuck in a situation where FTL has shut down 99% and cannot serve DNS until pihole -g finished running.

Related issue or feature (if applicable): Fixes #2395

Pull request in docs with documentation (if applicable): N/A

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I have commented my proposed changes within the code.
I am willing to help maintain this change if there are issues with it later.
It is compatible with the EUPL 1.2 license
I have squashed any insignificant commits. (git rebase)

Checklist:

The code change is tested and works locally.
I based my code and PRs against the repositories developmental branch.
I signed off all commits. Pi-hole enforces the DCO for all contributions
I signed all my commits. Pi-hole requires signatures to verify authorship
I have read the above and my PR is ready for review.

yubiuser · 2025-04-06T18:42:46Z

Why are we offering the gravity endpoint at all? Because we want to be able to run gravity from the web interface?

Im not sure if this is the right way to fix #2395 - maybe the external program should simply call pihole -g instead of using the API endpoint?

DL6ER · 2025-04-06T19:00:54Z

Why are we offering the gravity endpoint at all? Because we want to be able to run gravity from the web interface?

Yes

Im not sure if this is the right way to fix #2395 - maybe the external program should simply call pihole -g instead of using the API endpoint?

Yes, but my point here is that - as long as we are offering this - this can very well be considered a bug as FTL can be brought into a (temporary, but maybe long) defunct state until gravity finishes it can finally restart

yubiuser

It causes some logspam

2025-04-06 21:31:59.322 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:00.323 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:01.322 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:02.323 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:03.324 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:04.325 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:05.325 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:06.326 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:07.327 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:08.328 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:09.328 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:10.329 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:11.329 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:12.330 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:13.332 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:13.641 CEST [135290/T135558] INFO: Restarting FTL: API action request
2025-04-06 21:32:13.642 CEST [135290M] INFO: Asked to terminate by "/usr/bin/pihole-FTL -f" (PID 135290, user pihole UID 999)
2025-04-06 21:32:13.642 CEST [135290M] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:14.331 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:15.332 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:16.332 CEST [135290/T135309] INFO: Not restarting as gravity is still running...
2025-04-06 21:32:17.333 CEST [135290/T135309] INFO: Not restarting as gravity is still running...

__

This is working as expected, but something very 'gravity' specific. Shouldn't this be extended to all endpoints - only restart when the previous requests have been finished?

DL6ER · 2025-04-21T20:06:22Z

Sorry, seeing your reply only now. The gravity case is very special here because it is (really!) long-lived and can prevent FTL from shutting down. Is there any other action that is capable of doing something similar? I don't think so.

We can surely reduce the logging to do it ... once and then again every 30 seconds if still waiting? ...

yubiuser · 2025-04-21T20:23:24Z

We can surely reduce the logging to do it ... once and then again every 30 seconds if still waiting? ...

Yes please. And more importantly: Only start logging when gravity is running and a restart request has been received. As you can see in the log above the logging started when the gravity endpoint has been requested, and only 14 seconds later the restart requests was received.

yubiuser · 2025-05-13T07:03:21Z

I think this needs some attention from @DL6ER. I added some review points

Yes please. And more importantly: Only start logging when gravity is running and a restart request has been received. As you can see in the log above the logging started when the gravity endpoint has been requested, and only 14 seconds later the restart requests was received.

DL6ER · 2025-05-14T17:06:11Z

Added. I also just have seen your comment on #5815 and I don't actually think so. All this PR is doing is ensuring the DNS server is not shut down too early. The gravity process will - in any case be finished.

Having said that, I did just see a possible evasion of this: Assume the gravity runs really long (think minutes). DNS operation has stopped. Users may log in via SSH and force a restart of FTL using systemctl which cannot be stopped from within FTL.

However, even in this case, I don't think users will end up with a broken database as the gravity process has been designed to avoid this. We are always working on a temporary file the entire time until we swap the files at the very end. This should be an almost atomic operation and the likeliness that the process is interrupted at this very point seems ultra-low to me. But I may of course be wrong about this.

github-actions · 2025-06-24T17:26:31Z

This pull request has conflicts, please resolve those before we can evaluate the pull request.

…ing. This to prevent being stuck in a situation where FTL has shut down 99% and cannot serve DNS until pihole -g finished running Signed-off-by: DL6ER <[email protected]>

…ost every 30 seconds Signed-off-by: DL6ER <[email protected]>

github-actions · 2025-06-24T17:32:35Z

Conflicts have been resolved.

github-actions · 2025-09-14T18:43:05Z

This pull request has conflicts, please resolve those before we can evaluate the pull request.

Signed-off-by: Dominik <[email protected]>

github-actions · 2025-09-14T18:49:29Z

Conflicts have been resolved.

yubiuser

I'm not sure how I tested it last time, but now I tried it with two approaches and it killed gravity right away without printing any warning or waiting for gravity.

Triggered gravity from the web interface, then re-started resolver from Settings/System.
Triggered gravity from the web interface, then changed a setting that required a FTL restart

DL6ER · 2025-10-05T07:54:50Z

@yubiuser Did you meant to submit this as request for changes? If so, I'm not seeing an actual request.

yubiuser · 2025-10-05T08:08:00Z

Yes it is. The request is to make it work. Currently, a running gravity is killed without waiting when a FTL restart is triggered

Signed-off-by: Dominik <[email protected]>

DL6ER · 2025-10-05T08:21:51Z

Looking at the comment immediately revealed that the ! on the second variable shouldn't be there as this is the code part that prevents an early shutdown...

yubiuser

2025-10-05 11:50:32.551 CEST [172358/T172828] INFO: Restarting FTL: API action request
2025-10-05 11:50:32.552 CEST [172358M] INFO: Asked to terminate by "/usr/bin/pihole-FTL -f" (PID 172358, user pihole UID 999)
2025-10-05 11:50:32.552 CEST [172358M] INFO: Not terminating as gravity is still running...
2025-10-05 11:51:03.959 CEST [172358/T172818] INFO: Not terminating as gravity is still running...
2025-10-05 11:51:34.975 CEST [172358/T172818] INFO: Not terminating as gravity is still running...
2025-10-05 11:51:42.033 CEST [172358/T172820] INFO: Terminating timer thread
2025-10-05 11:51:42.044 CEST [172358/T172817] INFO: Terminating database thread
2025-10-05 11:51:42.329 CEST [172358M] INFO: Finished final database update
2025-10-05 11:51:42.330 CEST [172358M] INFO: Waiting for threads to join
2025-10-05 11:51:42.330 CEST [172358M] INFO: Thread housekeeper (1) is idle, terminating it.
2025-10-05 11:51:42.330 CEST [172358M] INFO: Thread dns-client (2) is idle, terminating it.

yubiuser · 2025-10-05T11:48:36Z

RISCV is constantly failing. Maybe needs a rebase/merge of development to include #2631

DL6ER · 2025-10-05T18:43:11Z

Merged latest development right now

github-actions · 2025-11-22T08:51:02Z

This pull request has conflicts, please resolve those before we can evaluate the pull request.

Signed-off-by: Dominik <[email protected]>

github-actions · 2025-11-25T19:11:08Z

Conflicts have been resolved.

DL6ER added the Bugfix label Apr 6, 2025

DL6ER requested a review from a team April 6, 2025 18:11

yubiuser reviewed Apr 6, 2025

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yubiuser mentioned this pull request Apr 27, 2025

SQL - no more rows available pi-hole/pi-hole#5815

Closed

rdwebdesign requested a review from a team May 13, 2025 01:07

github-actions bot added the Merge conflicts label Jun 24, 2025

DL6ER added 2 commits June 24, 2025 19:32

Do not try to restart FTL when a streamed pihole -g run is still ongo…

98d39f0

…ing. This to prevent being stuck in a situation where FTL has shut down 99% and cannot serve DNS until pihole -g finished running Signed-off-by: DL6ER <[email protected]>

Print gravity running warning only when wanting to terminate and at m…

9281118

…ost every 30 seconds Signed-off-by: DL6ER <[email protected]>

DL6ER force-pushed the tweak/prevent_restart_during_gravity_run branch from b503db3 to 9281118 Compare June 24, 2025 17:32

github-actions bot removed the Merge conflicts label Jun 24, 2025

yubiuser linked an issue Jul 22, 2025 that may be closed by this pull request

FTL takes 5 minutes to reboot? #2395

Open

Merge branch 'development' into tweak/prevent_restart_during_gravity_run

c4aa399

github-actions bot added the Merge conflicts label Sep 14, 2025

Merge branch 'development' into tweak/prevent_restart_during_gravity_run

a6ac5fb

Signed-off-by: Dominik <[email protected]>

github-actions bot removed the Merge conflicts label Sep 14, 2025

yubiuser requested changes Oct 4, 2025

View reviewed changes

Fix logic

1d82be7

Signed-off-by: Dominik <[email protected]>

yubiuser previously approved these changes Oct 5, 2025

View reviewed changes

Merge branch 'development' into tweak/prevent_restart_during_gravity_run

dccb526

github-actions bot added the Merge conflicts label Nov 22, 2025

Merge branch 'development' into tweak/prevent_restart_during_gravity_run

d437763

Signed-off-by: Dominik <[email protected]>

DL6ER enabled auto-merge November 25, 2025 19:11

github-actions bot removed the Merge conflicts label Nov 25, 2025

DL6ER dismissed yubiuser’s stale review via d437763 November 25, 2025 19:11

DL6ER requested a review from yubiuser November 25, 2025 19:19

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Do not restart FTL while pihole -g is still ongoing #2419

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DL6ER commented Apr 6, 2025

What does this implement/fix?

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Do not restart FTL while `pihole -g` is still ongoing #2419

Do not restart FTL while `pihole -g` is still ongoing #2419