++pexpect-timeout values in config.xxhc are ignored

[meermanr]

Local OS (where xxh is installed): Ubuntu 20.04 Destination host OS: n/a xxh version: xxh/0.8.10 xxh-plugins installed: none

Problem statement

Some hosts I want to use xxh with have very slow authentication procedures - I can see from ssh -vv that it takes ~20s for the remote end to accept my private key, and additional ~10s to then launch a shell. It an enterprise environment, and likely the delay is caused by audit procedures and mounting network drives etc.

By default xxh only waits 6s for the remote session to begin. By adding ++pexpect-timeout=60 to the command line I can extend this and use xxh without issue. However, I cannot seem to set the same via config.xxhc: it seems to be ignored!

Steps to Reproduce

For this experiment, I spun up a clean Ubuntu 20.04 LTS VM via Vagrant:

vagrant init bento/ubuntu-20.04 \
  && vagrant up \
  && vagrant ssh

and installed the latest portable xxh Linux binaries:

cd
mkdir xxh
cd xxh
wget https://github.com/xxh/xxh/releases/download/0.8.10-release2/xxh-portable-musl-alpine-Linux-x86_64.tar.gz
tar -xzf xxh-portable-musl-alpine-Linux-x86_64.tar.gz
./xxh

Below is my baseline test, showing the default behaviour of xxh. Note the presence of (timeout=6), and that I have not created a config.xxhc configuration file yet:

vagrant@ubuntu-20:~/xxh$ time ./xxh +vv  example.com </dev/null
ssh arguments: ['-o', 'StrictHostKeyChecking=accept-new']
RUN SHELL COMMAND: mkdir -v -p /home/vagrant/.xxh /home/vagrant/.xxh/.xxh/plugins /home/vagrant/.xxh/.xxh/shells
Pexpect command (timeout=6): bash -c 'echo -e "xxh_home_realpath=\$(dirname ~/.xxh)/\$(basename ~/.xxh)\n            xxh_version=\"dir_not_found\"\n            if [[ -d \$xxh_home_realpath ]]; then\n                xxh_version=\$([ \"\$(ls -A \$xxh_home_realpath)\" ] && echo \"version_not_found\" || echo \"dir_empty\")\n                settings_path=\$xxh_home_realpath/.xxh/xxh_version\n                if [[ -f \$settings_path ]]; then\n                    xxh_version=\$(cat \$settings_path)\n                fi\n            fi\n            echo xxh_home_realpath=\$xxh_home_realpath\n            echo xxh_version=\$xxh_version\n            echo xxh_shell_exists=\`[ -d \$xxh_home_realpath/.xxh/shells/xxh-shell-xonsh ] && echo \"1\" ||echo \"0\"\`\n            echo xxh_home_writable=\`[ -w \$xxh_home_realpath ] && echo \"1\" ||echo \"0\"\`\n            echo xxh_parent_home_writable=\$([ -w \$(dirname \$xxh_home_realpath) ] && echo \"1\" ||echo \"0\")\n            echo rsync=\`command -v rsync\`\n            echo scp=\`command -v scp\`\n            echo shell=\`command -v xonsh\`\n            echo kernel=\`uname -s\`\n            echo arch=\`uname -m\`" | ssh -v "-o" "StrictHostKeyChecking=accept-new" example.com -T "bash -s"'

If I specify ++pexpect-timeout at the command line the timeout notice changes to (timeout=60) as desired:`

vagrant@ubuntu-20:~/xxh$ time ./xxh +vv ++pexpect-timeout=60 example.com </dev/null
ssh arguments: ['-o', 'StrictHostKeyChecking=accept-new']
RUN SHELL COMMAND: mkdir -v -p /home/vagrant/.xxh /home/vagrant/.xxh/.xxh/plugins /home/vagrant/.xxh/.xxh/shells
Pexpect command (timeout=60): bash -c 'echo -e "xxh_home_realpath=\$(dirname ~/.xxh)/\$(basename ~/.xxh)\n            xxh_version=\"dir_not_found\"\n            if [[ -d \$xxh_home_realpath ]]; then\n                xxh_version=\$([ \"\$(ls -A \$xxh_home_realpath)\" ] && echo \"version_not_found\" || echo \"dir_empty\")\n                settings_path=\$xxh_home_realpath/.xxh/xxh_version\n                if [[ -f \$settings_path ]]; then\n                    xxh_version=\$(cat \$settings_path)\n                fi\n            fi\n            echo xxh_home_realpath=\$xxh_home_realpath\n            echo xxh_version=\$xxh_version\n            echo xxh_shell_exists=\`[ -d \$xxh_home_realpath/.xxh/shells/xxh-shell-xonsh ] && echo \"1\" ||echo \"0\"\`\n            echo xxh_home_writable=\`[ -w \$xxh_home_realpath ] && echo \"1\" ||echo \"0\"\`\n            echo xxh_parent_home_writable=\$([ -w \$(dirname \$xxh_home_realpath) ] && echo \"1\" ||echo \"0\")\n            echo rsync=\`command -v rsync\`\n            echo scp=\`command -v scp\`\n            echo shell=\`command -v xonsh\`\n            echo kernel=\`uname -s\`\n            echo arch=\`uname -m\`" | ssh -v "-o" "StrictHostKeyChecking=accept-new" example.com -T "bash -s"'

However, when I attempt to specify the same via this config.xxhc:

vagrant@ubuntu-20:~/xxh$ cat ~/.config/xxh/config.xxhc
hosts:
  ".*":
    ++pexpect-timeout: "60"

I observe that ++pexpect-timeout argument appears in the final argument list ( 👍 ), but not not affect the (timeout=) notice ( 👎 ):

vagrant@ubuntu-20:~/xxh$ time ./xxh +vv example.com </dev/null
Load xxh config from /home/vagrant/.config/xxh/config.xxhc
Load xxh config for host .*
Final arguments list: ['++pexpect-timeout', '60', '+vv', 'example.com']
ssh arguments: ['-o', 'StrictHostKeyChecking=accept-new']
RUN SHELL COMMAND: mkdir -v -p /home/vagrant/.xxh /home/vagrant/.xxh/.xxh/plugins /home/vagrant/.xxh/.xxh/shells
Pexpect command (timeout=6): bash -c 'echo -e "xxh_home_realpath=\$(dirname ~/.xxh)/\$(basename ~/.xxh)\n            xxh_version=\"dir_not_found\"\n            if [[ -d \$xxh_home_realpath ]]; then\n                xxh_version=\$([ \"\$(ls -A \$xxh_home_realpath)\" ] && echo \"version_not_found\" || echo \"dir_empty\")\n                settings_path=\$xxh_home_realpath/.xxh/xxh_version\n                if [[ -f \$settings_path ]]; then\n                    xxh_version=\$(cat \$settings_path)\n                fi\n            fi\n            echo xxh_home_realpath=\$xxh_home_realpath\n            echo xxh_version=\$xxh_version\n            echo xxh_shell_exists=\`[ -d \$xxh_home_realpath/.xxh/shells/xxh-shell-xonsh ] && echo \"1\" ||echo \"0\"\`\n            echo xxh_home_writable=\`[ -w \$xxh_home_realpath ] && echo \"1\" ||echo \"0\"\`\n            echo xxh_parent_home_writable=\$([ -w \$(dirname \$xxh_home_realpath) ] && echo \"1\" ||echo \"0\")\n            echo rsync=\`command -v rsync\`\n            echo scp=\`command -v scp\`\n            echo shell=\`command -v xonsh\`\n            echo kernel=\`uname -s\`\n            echo arch=\`uname -m\`" | ssh -v "-o" "StrictHostKeyChecking=accept-new" example.com -T "bash -s"'
Probably the connection takes more time than expected.
Try to increase the timeout by adding "++pexpect-timeout 10" argument.
Pexpect details:
<pexpect.pty_spawn.spawn object at 0x7f94119bc490>
command: /usr/bin/bash
args: ['/usr/bin/bash', '-c', 'echo -e "xxh_home_realpath=\\$(dirname ~/.xxh)/\\$(basename ~/.xxh)\\n            xxh_version=\\"dir_not_found\\"\\n            if [[ -d \\$xxh_home_realpath ]]; then\\n                xxh_version=\\$([ \\"\\$(ls -A \\$xxh_home_realpath)\\" ] && echo \\"version_not_found\\" || echo \\"dir_empty\\")\\n                settings_path=\\$xxh_home_realpath/.xxh/xxh_version\\n                if [[ -f \\$settings_path ]]; then\\n                    xxh_version=\\$(cat \\$settings_path)\\n                fi\\n            fi\\n            echo xxh_home_realpath=\\$xxh_home_realpath\\n            echo xxh_version=\\$xxh_version\\n            echo xxh_shell_exists=\\`[ -d \\$xxh_home_realpath/.xxh/shells/xxh-shell-xonsh ] && echo \\"1\\" ||echo \\"0\\"\\`\\n            echo xxh_home_writable=\\`[ -w \\$xxh_home_realpath ] && echo \\"1\\" ||echo \\"0\\"\\`\\n            echo xxh_parent_home_writable=\\$([ -w \\$(dirname \\$xxh_home_realpath) ] && echo \\"1\\" ||echo \\"0\\")\\n            echo rsync=\\`command -v rsync\\`\\n            echo scp=\\`command -v scp\\`\\n            echo shell=\\`command -v xonsh\\`\\n            echo kernel=\\`uname -s\\`\\n            echo arch=\\`uname -m\\`" | ssh -v "-o" "StrictHostKeyChecking=accept-new" example.com -T "bash -s"']
buffer (last 100 chars): b'nfig line 21: Applying options for *\r\r\ndebug1: Connecting to example.com [93.184.216.34] port 22.\r\r\n'
before (last 100 chars): b'nfig line 21: Applying options for *\r\r\ndebug1: Connecting to example.com [93.184.216.34] port 22.\r\r\n'
after: <class 'pexpect.exceptions.TIMEOUT'>
match: None
match_index: None
exitstatus: None
flag_eof: False
pid: 13198
child_fd: 5
closed: False
timeout: 30
delimiter: <class 'pexpect.exceptions.EOF'>
logfile: None
logfile_read: None
logfile_send: None
maxread: 2000
ignorecase: False
searchwindowsize: None
delaybeforesend: 0.05
delayafterclose: 0.1
delayafterterminate: 0.1
Answer from host is empty. Try again with +v or +vv or try ssh before xxh.

real	0m6.217s
user	0m0.101s
sys	0m0.008s
vagrant@ubuntu-20:~/xxh$

I have also tried using the key=value form of argument in the YAML, which again looked fine in the final argument list, but didn't have any affect:

hosts:
  ".*":
    ++pexpect-timeout=60: 

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