Re: [launchd-dev] Launching a process on demand?

7 Jul 2009


      On Jul 6, 2009, at 10:11 PM, Conrad Taylor wrote:
...
Hi, I'm attempting to configure the MySQL launchd plist file to  
launch MySQL process only when needed.  At this time, it's launched  
at boot/startup and it stays alive.  At this time, the script looks  
as follows:
BEGIN org.macports.mysql5.plist:
<?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>Debug</key>
  <false/>
  <key>Label</key>
  <string>org.macports.mysql5</string>
  <key>OnDemand</key>
  <false/>
  <key>ProgramArguments</key>
  <array>
      <string>/opt/local/bin/daemondo</string>
      <string>--label=mysql5</string>
      <string>--start-cmd</string>
      <string>/opt/local/etc/LaunchDaemons/org.macports.mysql5/ 
mysql5.wrapper</string>
      <string>start</string>
      <string>;</string>
      <string>--stop-cmd</string>
      <string>/opt/local/etc/LaunchDaemons/org.macports.mysql5/ 
mysql5.wrapper</string>
      <string>stop</string>
      <string>;</string>
      <string>--restart-cmd</string>
      <string>/opt/local/etc/LaunchDaemons/org.macports.mysql5/ 
mysql5.wrapper</string>
      <string>restart</string>
      <string>;</string>
      <string>--pid=none</string>
  </array>
  <key>RunAtLoad</key>
  <false/>
</dict>
</plist>
END org.macports.mysql5.plist:
When you start inserting semi-colons into your ProgramArguments, it's  
time to wrap it all up in a simple shell script.
...
I changed the above key/value pair to OnDemand/true.  Now, the  
process doesn't start when I try to access it by doing the following:
OnDemand is deprecated. If you want the job launched on-demand, you  
can define a Sockets dictionary or a MachServices dictionary. Though  
since you're dealing with MySQL, I'm guessing you want the former. To  
see an example of a job that's launched on-demand when there is a  
connection to a socket, check out the SampleD example and  
BetterAuthorizationSample.
...
Is there a manual which clearly describes these key/value pairs?  I  
guess I'm interested in the key/value pair, OnDemand, and when/how  
it works.
launchd.plist(5)
-- 
Damien Sorresso
BSD Engineering
Apple Inc.