Launchd wrangling

[Axel Luttgens]

On 23/07/07 11:14, Norman Gray wrote:

>
> Greetings.
>
> Can anyone advise me how to debug a launchd task?


Well, system.log should provide some info, especially when the task's 
plist has a "Debug" key (set to the boolean value true).
On the other hand, you could also have a look at the man page for 
launchd_debugd(8), even if it isn't likely to be of great help.

> [...]
>
>
> [1] This is in ~/Library/LaunchAgents:
>
> <?xml version="1.0" encoding="UTF-8"?>
> <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http:// 
> www.apple.
> com/DTDs/PropertyList-1.0.dtd">
> <plist version="1.0">
> <dict>
>         <key>LowPriorityIO</key>
>         <true/>
>         <key>Nice</key>
>         <integer>1</integer>
>         <key>ProgramArguments</key>
>         <array>
>                 <string>/Users/norman/local/bin/grok-battery-info</ 
> string>
>         </array>
>         <key>StartCalendarInterval</key>
>         <dict>
>                 <key>Hour</key>
>                 <integer>12</integer>
>                 <key>Minute</key>
>                 <integer>10</integer>
>         </dict>
>         <key>label</key>
>         <string>localhost.nxg-battery-status</string>
> </dict>
> </plist>


This must be the main source of the troubles you are encountering: 
LaunchAgents are somewhat problematic.
You may find more info about this in the thread "launchd question" that 
started on February, 27th.

Another problem is with launchd itself, when asked to perform 
periodic/calendar tasks: they are affected by some bugs since the early 
days of Tiger.
I would say that the most reliable way to handle such tasks is cron, 
which is still with us and very healthy.

HTH,
Axel