[launchd-dev] What is "Service only ran for XX seconds … Pushing respawn out …"

[Damien Sorresso]

Hi Jerry,

It's likely that your job is being relaunched because your WatchPath criterion is firing. Your ThrottleInterval is 60, which means that launchd will require that your job run for at least 60 seconds. If it does not, then launchd will not spawn it again until 60 seconds have passed since the last time it was run. (This is to amortize startup costs.) This behavior is described in launchd.plist(5). By default, it's 10 seconds.

You can see why launchd spawned your job on Yosemite by using the `launchctl print` subcommand. See the launchctl(1) man page for details. In that output will be the reason launchd ran the job (if the job is currently running).

Also, the sources you're looking at are out of date. launchd in Yosemite was rewritten, and it is part of the libxpc project, which is not open source. Though this particular behavior has not changed in the new implementation.
-damien

On 16 Nov, 2014, at 02:39, Jerry Krinock <jerry at ieee.org> wrote:
> My app installs a launchd job which watches a file and runs a tool whenever that file changes.  The tool typically runs for a few seconds and then terminates itself.  This has worked OK for years.  Yesterday, however, I noticed that launchd sometimes complains to the system log that my “Service” (??) ran for some number of seconds which is less than 60, and so it is “Pushing respawn out” by the difference in seconds between this duration that it supposedly “ran” and 60.  Example:
> 
> 14/11/16 3:31:54.822 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 25 seconds. Pushing respawn out by 35 seconds.
> 
> Does anyone have any idea what might be going on?  60 seconds happens to be the ThrottleInterval of the job, not the expected “run” time.  Am I running a “Service”?  (I don’t think so.)  Why might launchd think it needs to be “respawned”?
> 
> I’m on OS X 10.10.1 (14B17).  A sanitized version of my job’s plist, and a filtered console log, are below.  
> 
> I can’t find any of these strings in the latest launchd source, which might be at this link:
>    http://www.opensource.apple.com/source/launchd/launchd-842.92.1/src/
> But I’m *really* groping in the dark whenever I visit there.
> 
> Thank you,
> 
> Jerry Krinock 
> 
> 
> <?xml version="1.0" encoding="UTF-8"?>
> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
> <plist version="1.0">
> <dict>
> 	<key>Label</key>
> 	<string>MyLabel</string>
> 	<key>Nice</key>
> 	<integer>20</integer>
> 	<key>ProgramArguments</key>
> 	<array>
> 		<string>/path/to/MyTool</string>
> 		<string>MyArg1</string>
> 		<string>MyArg2</string>
> 	</array>
> 	<key>ThrottleInterval</key>
> 	<integer>60</integer>
> 	<key>WatchPaths</key>
> 	<array>
> 		<string>/path/to/MyFile</string>
> 	</array>
> </dict>
> </plist>
> 
> 
> 14/11/16 3:22:29.948 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 57 seconds. Pushing respawn out by 3 seconds.
> 14/11/16 3:25:05.659 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 59 seconds. Pushing respawn out by 1 seconds.
> 14/11/16 3:26:00.903 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 54 seconds. Pushing respawn out by 6 seconds.
> 14/11/16 3:30:29.608 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 0 seconds. Pushing respawn out by 60 seconds.
> 14/11/16 3:31:54.822 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 25 seconds. Pushing respawn out by 35 seconds.
> 14/11/16 3:33:20.050 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 50 seconds. Pushing respawn out by 10 seconds.
> 14/11/16 3:34:28.347 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 58 seconds. Pushing respawn out by 2 seconds.
> 14/11/16 3:48:24.681 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 0 seconds. Pushing respawn out by 60 seconds.
> 14/11/16 3:49:59.418 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 34 seconds. Pushing respawn out by 26 seconds.
> 14/11/16 3:51:22.418 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 56 seconds. Pushing respawn out by 4 seconds.
> 14/11/16 3:52:43.228 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 1 seconds. Pushing respawn out by 59 seconds.
> 14/11/16 3:54:14.707 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 32 seconds. Pushing respawn out by 28 seconds.
> 14/11/16 3:56:06.659 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 0 seconds. Pushing respawn out by 60 seconds.
> 14/11/16 3:57:07.151 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 0 seconds. Pushing respawn out by 60 seconds.
> 14/11/16 3:58:32.343 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 25 seconds. Pushing respawn out by 35 seconds.
> 14/11/16 4:00:43.205 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 0 seconds. Pushing respawn out by 60 seconds.
> 14/11/16 4:04:30.194 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 0 seconds. Pushing respawn out by 60 seconds.
> 14/11/16 4:06:03.763 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 33 seconds. Pushing respawn out by 27 seconds.
> 14/11/16 4:07:08.939 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 38 seconds. Pushing respawn out by 22 seconds.
> 14/11/16 4:08:09.133 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 38 seconds. Pushing respawn out by 22 seconds.
> 14/11/16 4:10:03.729 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 1 seconds. Pushing respawn out by 59 seconds.
> 14/11/16 4:11:37.160 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 34 seconds. Pushing respawn out by 26 seconds.
> 14/11/16 4:12:54.515 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 51 seconds. Pushing respawn out by 9 seconds.
> 14/11/16 4:14:50.649 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 0 seconds. Pushing respawn out by 60 seconds.
> 14/11/16 4:16:54.758 AM com.apple.xpc.launchd[1]: (MyLabel) Service only ran for 0 seconds. Pushing respawn out by 60 seconds.
> 
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