I am using paramiko package to create an SSH to my server.
I wrote the following code (part of my module) that should execute some command and return it's output.
def exec_and_get_remote_output(self, cmd, decode=True, splitlines=True, ssh_close=False):
"""
Execute remote command and return output
:param cmd: command to execute (string)
:param decode: perform decoding from binary (bool)
:param splitlines: perform splitting to get list of lines (bool)
:param ssh_close: close SSH session after execution (bool)
:return: command output as sting or list of lines
"""
if CHECK_NONE(self._client):
logger.debug('ssh client is None')
return None
if not self._opened:
self.open_connection()
chan = self._client.get_transport().open_session()
chan.exec_command(cmd)
logger.debug('Executed SSH command: {}'.format(cmd))
raw_output = self.receive_output(chan)
if decode and splitlines:
output = self._decode_raw(raw_output)
elif decode and not splitlines:
output = self._decode_raw(raw_output, splitlines=False)
else:
output = raw_output
logger.debug('Raw output:\n{}'.format(output))
# Perform cleanup
self.cleanup(chan, ssh_close)
return output
This Code should execute some command (passed as a string) and then parse the output from the channel.
When I call this method with simple shell command I get the output as needed.
[ for example: print(self.ssh.exec_and_get_remote_output("ls"))]
Now , my problem invokes when I try to run some CLI process inside this server shell that should get input from the shell (user input) and return the output to the shell (print it on screen) , In this case chan.exec_command is returning me None (NoneType) instead of [stdin,stdout,stderr] tuple and raw_output variable (the output from the channel) is alsor returned as None and therefore nothing is printed eventually , moreover, I don't get any exception SshException thrown so that I understand that executing this command was successful.
This is very strange because when I do this interactively (connecting manually to the server) and running the commands that connecting to the shell everything prints O.K. on the terminal.
[ example : print(self.ssh.get_remote_output("echo -e 'show cable rpd' | /opt/confd/bin/confd_cli --noaaa "))]
I read exec_command user manual and didn't see anything that should cause such behaviour.
This is the log I get from the logger:
DEBUG:paramiko.transport:starting thread (client mode): 0x75a745c0
DEBUG:paramiko.transport:Local version/idstring: SSH-2.0-paramiko_2.4.2
DEBUG:paramiko.transport:Remote version/idstring: SSH-2.0-OpenSSH_7.4p1 Debian-10+deb9u6
INFO:paramiko.transport:Connected (version 2.0, client OpenSSH_7.4p1)
DEBUG:paramiko.transport:kex algos:['curve25519-sha256', '[email protected]', 'ecdh-sha2-nistp256', 'ecdh-sha2-nistp384', 'ecdh-sha2-nistp521', 'diffie-hellman-group-exchange-sha256', 'diffie-hellman-group16-sha512', 'diffie-hellman-group18-sha512', 'diffie-hellman-group14-sha256', 'diffie-hellman-group14-sha1'] server key:['ssh-rsa', 'rsa-sha2-512', 'rsa-sha2-256', 'ecdsa-sha2-nistp256', 'ssh-ed25519'] client encrypt:['[email protected]', 'aes128-ctr', 'aes192-ctr', 'aes256-ctr', '[email protected]', '[email protected]'] server encrypt:['[email protected]', 'aes128-ctr', 'aes192-ctr', 'aes256-ctr', '[email protected]', '[email protected]'] client mac:['[email protected]', '[email protected]', '[email protected]', '[email protected]', '[email protected]', '[email protected]', '[email protected]', 'hmac-sha2-256', 'hmac-sha2-512', 'hmac-sha1'] server mac:['[email protected]', '[email protected]', '[email protected]', '[email protected]', '[email protected]', '[email protected]', '[email protected]', 'hmac-sha2-256', 'hmac-sha2-512', 'hmac-sha1'] client compress:['none', '[email protected]'] server compress:['none', '[email protected]'] client lang:[''] server lang:[''] kex follows?False
DEBUG:paramiko.transport:Kex agreed: ecdh-sha2-nistp256
DEBUG:paramiko.transport:HostKey agreed: ssh-ed25519
DEBUG:paramiko.transport:Cipher agreed: aes128-ctr
DEBUG:paramiko.transport:MAC agreed: hmac-sha2-256
DEBUG:paramiko.transport:Compression agreed: none
DEBUG:paramiko.transport:kex engine KexNistp256 specified hash_algo <built-in function openssl_sha256>
DEBUG:paramiko.transport:Switch to new keys ...
DEBUG:paramiko.transport:Adding ssh-ed25519 host key for [10.40.2.142]:2022: b'c145a1e3b7fc4252387d5930a73cc2c9'
DEBUG:paramiko.transport:userauth is OK
INFO:paramiko.transport:Authentication (password) successful!
DEBUG:framework.ssh_client:SSH connection to 10.40.2.142:2022 is open
DEBUG:framework.ssh_client:This message should appear on the console:
DEBUG:paramiko.transport:[chan 0] Max packet in: 32768 bytes
DEBUG:paramiko.transport:Received global request "[email protected]"
DEBUG:paramiko.transport:Rejecting "[email protected]" global request from server.
DEBUG:paramiko.transport:[chan 0] Max packet out: 32768 bytes
DEBUG:paramiko.transport:Secsh channel 0 opened.
DEBUG:framework.ssh_client:Executed SSH command: /opt/confd/bin/confd_cli --noaaa
DEBUG:framework.ssh_client:Attempt #1 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #2 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #3 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #4 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #5 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #6 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #7 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #8 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #9 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #10 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #11 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #12 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #13 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #14 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #15 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #16 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #17 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #18 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #19 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #20 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #21 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #22 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #23 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #24 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #25 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #26 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #27 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #28 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #29 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #30 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #31 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #32 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #33 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #34 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #35 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #36 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #37 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #38 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #39 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #40 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #41 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #42 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #43 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #44 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #45 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #46 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #47 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #48 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #49 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #50 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #51 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #52 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #53 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #54 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #55 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #56 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #57 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #58 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #59 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #60 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #61 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #62 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #63 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #64 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #65 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #66 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #67 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #68 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #69 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #70 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #71 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #72 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #73 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #74 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #75 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #76 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #77 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #78 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #79 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #80 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #81 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #82 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #83 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #84 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #85 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #86 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #87 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #88 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #89 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #90 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #91 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #92 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #93 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #94 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #95 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #96 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #97 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #98 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #99 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #100 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Data is not ready to be read from channel. All 100 attempts are exhausted
DEBUG:framework.ssh_client:ERROR: Unable to get remote output
DEBUG:framework.ssh_client:Raw output:
None
DEBUG:paramiko.transport:[chan 0] EOF sent (0)
