Ruby background process STDOUT is empty

I'm having a weird issue with a start-up script which runs a Sinatra script using the shell's "daemon" function. The problem is that when I run the command at the command line, I get output to STDOUT. If I run the command at the command line exactly as it is in the script -- less the daemon part -- the output is correctly redirected to the output file. However, when the startup script runs it (see below), I get stuff to the STDERR log but not to the STDOUT log.

The relevant lines of the script:

#!/bin/sh
# (which is and has been a symlink to /bin/bash

# Source function library.
. /etc/init.d/functions

# Set Some Variables
RUNAS="joeuser"
PID=/var/run/myapp.pid
LOG="/var/log/myapp/app-out.log"
ERR_LOG="/var/log/myapp/app-err.log"
APPLICATION_COMMAND="RAILS_ENV=production ruby /opt/myapp/lib/daemons/my-sinatra-app.rb -p 8002 2>>${ERR_LOG} >>${LOG} &"

# Snip a bunch. This is the applicable line from the "start" case:
daemon --user $RUNAS --pidfile $PID $APPLICATION_COMMAND &> /dev/null

Now, the funky parts:

• The error log is written to correctly via the redirect of STDERR.
• If I reverse the order of the >> and the 2>> (I'm grasping at straws, here!), the behavior does not change: I still get STDERR logged correctly and STDOUT is empty.
• If the output log doesn't exist, the STDOUT redirect creates the file. But, the file remains 0-length.
• This used to work. The log directory is maintained by log-rotate. All of the more-recent 'out' logs are 0-length. The older ones are not. It seems like it stopped working some time in April. The ruby code didn't change at any time near then; neither did the startup script.

We're running three different services in this way. Two of them are ruby daemons (one uses sinatra, one does not) and the other is a background java process. This is occurring for BOTH of the ruby processes but is not happening on the java process. Maybe something changed in Ruby?

FTR, we've got ruby 1.8.5 and RHEL 5.4.

I've done some more probing. The daemon function does a bunch of stuff, but the meat of the matter is that it runs the program using runuser. The command essentially looks like this:

runuser -s /bin/bash - joeuser -c "ulimit -S -c 0 >/dev/null 2>&1 ; RAILS_ENV=production ruby /opt/myapp/lib/daemons/my-sinatra-app.rb -p 8002 '</dev/null' '>>/var/log/myapp/app-out.log' '2>>/var/log/myapp/app-开发者_StackOverflow中文版err.log' '&'"

When I run exactly that at the command line (both with and without the single-ticks that got added somewhere along the line), I get the exact same screwy behavior w.r.t. the output log. So, it seems to me that this is an issue of how ruby (?) interacts with runuser?

Too long to put in a comment :-)

change the shebang to add #!/bin/sh -x and verify that everything is expanded according to your expectations. Also, when executing from terminal, your .bashrc file is sourced, when executing from script, it is not; might be something in you're environment that differ. One way to find out is to do env from terminal and from script and diff the output

• env > env_terminal
• env > env_script
• diff env_terminal env_script

Happy hunting...