Re: sFTP - the sequel

hi John,

You'll want to change your Expect script so that it returns a non-zero
exit status when something fails. The way you have it written, each
line either succeeds or times out -- but you don't tell it what to do
when it times out.

So I'd code it more like this:

#!/usr/local/bin/expect -f
set timeout 20
spawn sftp -v ${USER}@ftp.xxx.com
expect {
default {exit 2}
"Connecting to gateway.klements.com..."
}
expect {
default {exit 2}
"continue connecting (yes/no)?" {send "yes\n"; exp_continue}
"assword:"
}
send "${PASSWORD}\n"
expect {
default {exit 2}
"sftp>"
}
send "cd expecttest\n"
expect {
default {exit 2}
"sftp>"
}
send "put ${PUTFILE}\n"
expect {
default {exit 2}
"not found" {exit 3}
"sftp>"
}
send "put ${PUTFILE2}\n"
expect {
default {exit 2}
"not found" {exit 3}
"sftp>"
}
send "quit\n"
exit 0




The word "default" is a special value in Expect. When either the
spawned utility ends prematurely, or a timeout occurs, the Expect tool
will run whatever you've coded under "default". In the above example,I
had it do an "exit 2", which means the Expect script will terminate with
exit status 2.

So if it sends a password, and that password doesn't work... the next
expect { } group will time-out after 20 seconds, and when that timeout
occurs, it'll do an "exit 2" and cause that exit status of 2 to be
returned to your shell script.

The next thing... the shell script needs to return that exit status
back to the CL program. So you can't simply end the shell script
normally, you need the shell script to get the error, and then return it
to the CL.


build_script | /usr/local/bin/expect -f -
exit $?

The "$?" returns the exit status of the last run command. So when you
do "exit $?" it'll take the exit status of the last run command and
return it to the CL program.

Hope that helps.


John McKee wrote:

Hi Scott,

I had suspected that the return value was from the expect command. I have
located a web page of Tcl commands. Not sure how to get the return value back
to a CL program.

I had thought sftp was running asynchronously as it was a spawned
process. Not
the same as a forked process, but still a different process.

One thought I had was for the status of the sftp command to be placed in an
environment variable to be tested by the CL program. Odd, but I don't
see a CL
command to retrieve the value of an environment variable for testing. What I
did years ago in scripts was put a command within an exit(). I thought that
might work here, but I don't see how to do that with the spawn function being
involved. And I would still need to get the value back to the calling CL. Is
this possible?

John McKee

Quoting Scott Klement <midrange-l@xxxxxxxxxxxxxxxx>:

Hi John,

Not sure why you think it's running asynchronously...

You aren't running sftp -- not directly at any rate -- you're running
expect. Your code is checking to see if expect is ending normally NOT
if sftp is ending normally. So if sftp fails, you have nothing to
detect that.

You need to code expect to look for the failed sftp, and then notify the
calling CL of the failure.



John McKee wrote:

Some issues have arisen. I don't know if there is a way to detect them.

A coworker sends huge files, 500M+, every day. Yesterday, the
expect script did
not even make it past the password prompt. No file transfer happened. The
expect script ran to the bottom. There was code to retrieve the
status of the
last command. But, it was zero, so no error.

Today, same script, different huge data files. Script runs to
completion. No
idea if the data files arrived on the remote site. Below is my
expect script,
slightly edited to remove actual destination:

#!/bin/sh

build_script() {

cat <<End-of-message
#!/usr/local/bin/expect -f
set timeout 20
spawn sftp -v ${USER}@ftp.xxx.com
expect "Connecting to ftp.xxx.com...\r\n"
expect "password:"
send "${PASSWORD}\n"
expect "sftp>"
send "put ${PUTFILE} \n"
expect "sftp>"
expect "sftp>"
send "put ${PUTFILE2} \n"
expect "sftp>"
send "quit\n"
exit
End-of-message

}

build_script | /usr/local/bin/expect -f -



Is there something there that causes the actual file transfer to occur
asynchronously, thus not allowing the status to be known to the original
caller?

This is the CL that calls the sFTP script:

CALL QP2SHELL PARM('/usr/bin/sh' '-b' +
'/usr/local/bin/xxx.scr')

/* Check for sFTP error */
CALL PGM(QUSRJOBI) PARM(&RCVVAR +
&RCVVARLEN +
'JOBI0600' +
'*' +
' ' )
IF (%BIN(&RCVVAR 109 4) *NE 0) DO

With the inclusion of the '-b', I am guessing that is why the sFTP
is running
asynchronously. My guess. This looks like the only thing that is
checked is
whether some part of QP2SHELL has completed, but not the entire script. Is
there some way to pause the CL until the underlying QP2SHELL has completed?

John McKee

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