Expect script is not exiting with code I set it to - expect

Question

I tried posting this in the codereview community, but there is no expect tag and I don't have enough karma to create tags.
I have written an expect script to either login to a server or run a simple (usually single) command and return the output.
I have two problems and a wish.
Commands that return nothing--i.e., ssh2server user host false--time out with an error (because I'm not capturing a timeout, though I suppose I should) instead of just returning nothing.
I can capture the return code of the program but I can't get it to exit with the appropriate code.
Is there a way I can take the output of the called program and return it the same way (remote stdout goes to local stdout and remote stderr goes to local stderr)?
Also, any comments or (constructive) criticisms would be appreciated.
#!/usr/bin/expect -f
if {[info exists ::env(SSH2SERVER_PASSWORD)]} {
set password "$env(SSH2SERVER_PASSWORD)"
} else {
puts "SSH2SERVER_PASSWORD not set"
exit 1
}
if {[llength $argv] < 2} {
puts "usage: ssh2server user server"
exit 1
}
set user [lindex $argv 0]
set server [lindex $argv 1]
set command [lrange $argv 2 end]
set pwd_prompt "*assword:"
set prompt "\$ "
set rc 0
expect_before {
#timeout { send_user 'timeout' ; exit 2 }
timeout { send_user 'timeout' ; set rc 2}
}
log_user 0
spawn ssh $user#$server
expect "$pwd_prompt" { send -- "$password\r" }
if { $command == "" } {
interact
} else {
expect {
"$prompt" {
send -- "PROMPT_COMMAND=\rPS1='_MYPROMPT_'\r$command\r"
#expect -re "$command\r\n(.*)\r\n\[^\r]*\[#\$%]"
expect -re "$command\r\n(.*)\r\n\[^\r]*_MYPROMPT_"
set results $expect_out(1,string)
puts $results
send -- "^D"
expect eof
#catch wait ec
#set rc [lindex $ec 3]
#puts [lindex $ec 3]
#exit [lindex $ec 3]
}
#eof { send_user $expect_out(buffer); exit 3}
eof { send_user $expect_out(buffer); set rc 3}
}
}
log_user 1
lassign [wait] pid spawnid os_flag rc
#puts $rc # outputs correct value
exit $rc

Answer 1

I suspect this is the problem:
send -- "^D"
You are not sending a Ctrl-D, you are sending the characters ^ and D.
To send a Ctrl-D
send -- "\04"
To solve the "no output, timeout" problem, you need to alter your expected regex: you have too many newlines for that case. Using expect -d would have revealed this to you. Like this:
send -- "unset PROMPT_COMMAND; PS1='_MYPROMPT_'\r"
expect -re "_MYPROMPT_$"
send -- "$command\r"
expect -re "$command(.*)\r\n_MYPROMPT_$"
The content of the capturing parentheses may now be empty.
I split off setting the prompt for clarity.
To capture the exit status of the command, you may have to do this:
send -- "$command; echo $?\r"
expect -re "$command(.*)\r\n(\d+)\r\n_MYPROMPT_$"
set results [regsub {^\r\n} $expect_out(1,string) ""]
set status $expect_out(2,string)
I don't think you can separate stdout and stderr with the expect command. I think both streams are captured as "output". (I don't have my Exploring Expect book nearby to confirm)
If that's important, you might want to invoke the command redirecting stdout and/or stderr to file(s), and then cat and capture the file contents.