How can I debug a Launchd script that doesn't run on startup?

问题

I have some Launchd scripts from homebrew. However I have to manually run them when I restart my computer:

launchctl load -w ~/Library/LaunchAgents/com.mysql.mysqld.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>KeepAlive</key>
  <true/>
  <key>Label</key>
  <string>com.mysql.mysqld</string>
  <key>Program</key>
  <string>/Users/dash/.local/Cellar/mysql/5.1.49/bin/mysqld_safe</string>
  <key>RunAtLoad</key>
  <true/>
  <key>UserName</key>
  <string>dash</string>
  <key>WorkingDirectory</key>
  <string>/Users/dash/.local/var</string>
</dict>
</plist>

I thought this should happen on startup. What am I missing?

回答1:

Best way I found to debug, in your plist:

<key>StandardErrorPath</key>
<string>/tmp/mycommand.err</string>
<key>StandardOutPath</key>
<string>/tmp/mycommand.out</string>

Open Console app, in "All Messages" you should see entries when your app fails or succeeds. Like this:

4/28/15 10:43:19.938 AM com.apple.xpc.launchd[1]: (mycommand[18704]) Service exited with abnormal code: 1

The issue I had was with ProgramArguments takes each item of command as <string> item in the array.

EDIT: In my case, generating a simple wrapper for shell script worked even better. This script sets up basic folder structure to make a shell script into an OS X "app" - https://gist.github.com/mathiasbynens/674099. This might work better for your mysql -u arg1 command.

回答2:

One possibility: Look in the directory:

/private/var/db/launchd.db/

and fine the "com.apple.launchd.peruser.###" file for your user. Open that and see if there is a entry like:

<key>com.mysql.mysqld.plist</key>
<dict>
    <key>Disabled</key>
    <true/>
</dict>

If so, try setting it to <false/>. Another file to look in for the same thing is:

/private/var/db/launchd.db/com.apple.launchd/overrides.plist

回答3:

The start command expects the job Label as it's argument, so you would start it using the following...

launchctl start com.myfile.hostname.plist

To stop, simply do the following...

launchctl stop com.myfile.hostname.plist

Once all your testing is complete you would log out then in to load it or if your plist file is in the users Library folder type the following...

launchctl load ~/Library/LaunchAgents/com.myfile.hostname.plist

回答4:

Try renaming it. Change the filename to:

~/Library/LaunchAgents/com.mysql.mysqld2.plist

and the Label section in the plist to:

<key>Label</key>
<string>com.mysql.mysqld2</string>

If you save a backup copy, make sure to move it outside of your ~/Library/LaunchAgents/ directory.

Finally, instead of using launchctl to load it, just logout and log back in. That will let launchd pick it up from your "LaunchAgents" directory by itself and take one more variable (i.e. launchctl) out of the mix.

回答5:

For me, other solutions so far do not help me. My problem is kinda hard to debug, because the plist file is correct, the script is running fine alone in a terminal. Everything looks fine, but doesn't work.

I checked the log file by executing

tail -f /var/log/system.log

And then by unloading and loading the service again with the commands:

launchctl unload ~/Library/LaunchAgents/example.plist
launchctl load ~/Library/LaunchAgents/example.plist

I found an error message from the log file:

Program specified by service is not a Mach-O executable file.

What does it really mean? I didn't google. But, I feel it's because I didn't add #!/bin/bash at the beginning of the shell script. Because I am lazy to add this line sometimes.

After adding the heading, everything works fine.

来源：https://stackoverflow.com/questions/6337513/how-can-i-debug-a-launchd-script-that-doesnt-run-on-startup

标签

macos

launchd