I have requirement to connect to one remote host and perform set of operation using python script like grep for files and check whether DB is running or not .
This what sample code i got
import subprocess
import sys
HOST="yyy03xxx.us.kkk.com"
# Ports are handled in ~/.ssh/config since we use OpenSSH
COMMAND="uname -a"
ssh = subprocess.Popen(["ssh", "%s" % HOST, COMMAND],
shell=False,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
result = ssh.stdout.readlines()
if result == []:
error = ssh.stderr.readlines()
print >>sys.stderr, "ERROR: %s" % error
else:
print result
Please suggest how can i modify this code to multiple operation
Related
I am writing a program in python on Ubuntu, to execute a command ls -l on RaspberryPi, connect with Network.
Can anybody guide me on how do I do that?
Sure, there are several ways to do it!
Let's say you've got a Raspberry Pi on a raspberry.lan host and your username is irfan.
subprocess
It's the default Python library that runs commands.
You can make it run ssh and do whatever you need on a remote server.
scrat has it covered in his answer. You definitely should do this if you don't want to use any third-party libraries.
You can also automate the password/passphrase entering using pexpect.
paramiko
paramiko is a third-party library that adds SSH-protocol support, so it can work like an SSH-client.
The example code that would connect to the server, execute and grab the results of the ls -l command would look like that:
import paramiko
client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect('raspberry.lan', username='irfan', password='my_strong_password')
stdin, stdout, stderr = client.exec_command('ls -l')
for line in stdout:
print line.strip('\n')
client.close()
fabric
You can also achieve it using fabric.
Fabric is a deployment tool which executes various commands on remote servers.
It's often used to run stuff on a remote server, so you could easily put your latest version of the web application, restart a web-server and whatnot with a single command. Actually, you can run the same command on multiple servers, which is awesome!
Though it was made as a deploying and remote management tool, you still can use it to execute basic commands.
# fabfile.py
from fabric.api import *
def list_files():
with cd('/'): # change the directory to '/'
result = run('ls -l') # run a 'ls -l' command
# you can do something with the result here,
# though it will still be displayed in fabric itself.
It's like typing cd / and ls -l in the remote server, so you'll get the list of directories in your root folder.
Then run in the shell:
fab list_files
It will prompt for an server address:
No hosts found. Please specify (single) host string for connection: irfan#raspberry.lan
A quick note: You can also assign a username and a host right in a fab command:
fab list_files -U irfan -H raspberry.lan
Or you could put a host into the env.hosts variable in your fabfile. Here's how to do it.
Then you'll be prompted for a SSH password:
[irfan#raspberry.lan] run: ls -l
[irfan#raspberry.lan] Login password for 'irfan':
And then the command will be ran successfully.
[irfan#raspberry.lan] out: total 84
[irfan#raspberry.lan] out: drwxr-xr-x 2 root root 4096 Feb 9 05:54 bin
[irfan#raspberry.lan] out: drwxr-xr-x 3 root root 4096 Dec 19 08:19 boot
...
Simple example from here:
import subprocess
import sys
HOST="www.example.org"
# Ports are handled in ~/.ssh/config since we use OpenSSH
COMMAND="uname -a"
ssh = subprocess.Popen(["ssh", "%s" % HOST, COMMAND],
shell=False,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
result = ssh.stdout.readlines()
if result == []:
error = ssh.stderr.readlines()
print >>sys.stderr, "ERROR: %s" % error
else:
print result
It does exactly what you want: connects over ssh, executes command, returns output. No third party library needed.
You may use below method with linux/ Unix 's built in ssh command.
import os
os.system('ssh username#ip bash < local_script.sh >> /local/path/output.txt 2>&1')
os.system('ssh username#ip python < local_program.py >> /local/path/output.txt 2>&1')
Paramiko module can be used to run multiple commands by invoking shell. Here I created class to invoke ssh shell
class ShellHandler:
def __init__(self, host, user, psw):
logger.debug("Initialising instance of ShellHandler host:{0}".format(host))
try:
self.ssh = paramiko.SSHClient()
self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
self.ssh.connect(host, username=user, password=psw, port=22)
self.channel = self.ssh.invoke_shell()
except:
logger.error("Error Creating ssh connection to {0}".format(host))
logger.error("Exiting ShellHandler")
return
self.psw=psw
self.stdin = self.channel.makefile('wb')
self.stdout = self.channel.makefile('r')
self.host=host
time.sleep(2)
while not self.channel.recv_ready():
time.sleep(2)
self.initialprompt=""
while self.channel.recv_ready():
rl, wl, xl = select.select([ self.stdout.channel ], [ ], [ ], 0.0)
if len(rl) > 0:
tmp = self.stdout.channel.recv(24)
self.initialprompt=self.initialprompt+str(tmp.decode())
def __del__(self):
self.ssh.close()
logger.info("closed connection to {0}".format(self.host))
def execute(self, cmd):
cmd = cmd.strip('\n')
self.stdin.write(cmd + '\n')
#self.stdin.write(self.psw +'\n')
self.stdin.flush()
time.sleep(1)
while not self.stdout.channel.recv_ready():
time.sleep(2)
logger.debug("Waiting for recv_ready")
output=""
while self.channel.recv_ready():
rl, wl, xl = select.select([ self.stdout.channel ], [ ], [ ], 0.0)
if len(rl) > 0:
tmp = self.stdout.channel.recv(24)
output=output+str(tmp.decode())
return output
If creating different shell each time does not matter to you then you can use method as below.
def run_cmd(self,cmd):
try:
cmd=cmd+'\n'
#self.ssh.settimeout(60)
stdin,stdout,stderr=self.ssh.exec_command(cmd)
while not stdout.channel.eof_received:
time.sleep(3)
logger.debug("Waiting for eof_received")
out=""
while stdout.channel.recv_ready():
err=stderr.read()
if err:
print("Error: ",my_hostname, str(err))
return False
out=out+stdout.read()
if out:
return out
except:
error=sys.exc_info()
logger.error(error)
return False
My Linux script is as below to ssh to host & search patch update which has kernel update
for host in `cat patch.csv`
do
echo "Host $host" >> /tmp/patching
ssh -o "UserKnownHostsFile=/dev/null" -o "StrictHostKeyChecking=no" $host 'sudo yum check-update | grep "kernel.x86"'>>/tmp/patching
done
Now i am trying to write a python script equivalent to this & its showing error(not able to conenct to ssh). I tried to use subprocess comamnd which is not working - its not able to pick up hostname & public key error.
import subprocess
import os
def read_file():
# Read and print the entire file line by line
with open('patch.csv', 'r') as reader:
with open('server_names.txt', 'w') as writer:
for host in reader:
writer.write(host)
p = subprocess.Popen(["ssh -o 'UserKnownHostsFile=/dev/null' -o 'StrictHostKeyChecking=no' host 'sudo yum check-update | grep kernel.x86'"], shell=True, stdout=subprocess.PIPE)
output, err = p.communicate()
print(host)
print("file read done")
read_file()
You can use paramiko to solve that problem to ssh to another host using python, we use it on an internal project, works very well.
http://www.paramiko.org/
$ pip install paramiko
You can use password or passphrase as input if it's required by the host, so authentication can be automated.
http://docs.paramiko.org/en/stable/api/client.html#paramiko.client.SSHClient.connect
connect(hostname, port=22, username=None, password=None, pkey=None, key_filename=None, timeout=None, allow_agent=True, look_for_keys=True, compress=False, sock=None, gss_auth=False, gss_kex=False, gss_deleg_creds=True, gss_host=None, banner_timeout=None, auth_timeout=None, gss_trust_dns=True, passphrase=None, disabled_algorithms=None)
Connect to an SSH server and authenticate to it. The server’s host key is checked against the system host keys (see load_system_host_keys) and any local host keys (load_host_keys). If the server’s hostname is not found in either set of host keys, the missing host key policy is used (see set_missing_host_key_policy). The default policy is to reject the key and raise an SSHException.
Code sample adapted from https://gist.github.com/mlafeldt/841944
import paramiko
hostname = host
password = pass123
command = 'sudo yum check-update | grep kernel.x86'
username = "admin"
port = 22
try:
client = paramiko.SSHClient()
client.load_system_host_keys()
client.set_missing_host_key_policy(paramiko.WarningPolicy)
client.connect(hostname, port=port, username=username, password=password)
stdin, stdout, stderr = client.exec_command(command)
print stdout.read()
finally:
client.close()
I got some idea from your given code #lucasgvarela & came up with this using some other posts in stackoverflow which actually worked.
import subprocess
import sys
# Ports are handled in ~/.ssh/config since we use OpenSSH
COMMAND="uname -a"
COMMAND2="UserKnownHostsFile=/dev/null"
COMMAND3="StrictHostKeyChecking=no"
with open('patch.csv', 'r') as reader:
with open('server_names.txt', 'w') as writer:
for HOST in reader:
print(HOST)
HOST=HOST.strip()
ssh = subprocess.Popen(["ssh","-o",COMMAND2,"-o",COMMAND3, "%s" % HOST, COMMAND],
shell=False,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
result = ssh.stdout.readlines()
if result == []:
error = ssh.stderr.readlines()
# print >>sys.stderr, "ERROR: %s" % error
writer.write(f'The Host failed is {HOST} & the error is {error}')
print(error)
else:
print (result)
You can use "sshscript" package. For the above shell script, it might be able to convert to python script of sshscript-syntax like this:
# filename: test.spy
with open('patch.csv') as fd:
for host in fd:
host = host.strip()
account = f'user#{host}'
$$echo "Host #{host}" >> /tmp/patching
$$ssh -o "UserKnownHostsFile=/dev/null" -o "StrictHostKeyChecking=no" #{account} 'sudo yum check-update | grep "kernel.x86"'>>/tmp/patching
Executing command on console:
$ sshscript test.spy
The link to documents of the sshscript package:
https://iapyeh.github.io/sshscript/index
I have written a below script to do ssh and providing password .But it still waits for password prompt while running . Searched through many such questions on stack overflow, Everyone suggesting to use paramiko or pexpect but I can not use this as this script has to be run by many people on different machines and can not ask everyone to install these libraries first
Looking for a solution without using such libraries
import subprocess
import sys
HOST="lab#xxxx"
COMMAND="pwd"
ssh = subprocess.Popen(["ssh", "%s" % HOST, COMMAND], shell=False, stdout=subprocess.PIPE, stdin = subprocess.PIPE, stderr=subprocess.PIPE)
ssh.stdin.write('lab\n')
ssh.stdin.flush()
result = ssh.stdout.readlines()
if result == []:
error = ssh.stderr.readlines()
print >>sys.stderr, "ERROR: %s" % error
else:
print result
~
I am writing a program in python on Ubuntu, to execute a command ls -l on RaspberryPi, connect with Network.
Can anybody guide me on how do I do that?
Sure, there are several ways to do it!
Let's say you've got a Raspberry Pi on a raspberry.lan host and your username is irfan.
subprocess
It's the default Python library that runs commands.
You can make it run ssh and do whatever you need on a remote server.
scrat has it covered in his answer. You definitely should do this if you don't want to use any third-party libraries.
You can also automate the password/passphrase entering using pexpect.
paramiko
paramiko is a third-party library that adds SSH-protocol support, so it can work like an SSH-client.
The example code that would connect to the server, execute and grab the results of the ls -l command would look like that:
import paramiko
client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect('raspberry.lan', username='irfan', password='my_strong_password')
stdin, stdout, stderr = client.exec_command('ls -l')
for line in stdout:
print line.strip('\n')
client.close()
fabric
You can also achieve it using fabric.
Fabric is a deployment tool which executes various commands on remote servers.
It's often used to run stuff on a remote server, so you could easily put your latest version of the web application, restart a web-server and whatnot with a single command. Actually, you can run the same command on multiple servers, which is awesome!
Though it was made as a deploying and remote management tool, you still can use it to execute basic commands.
# fabfile.py
from fabric.api import *
def list_files():
with cd('/'): # change the directory to '/'
result = run('ls -l') # run a 'ls -l' command
# you can do something with the result here,
# though it will still be displayed in fabric itself.
It's like typing cd / and ls -l in the remote server, so you'll get the list of directories in your root folder.
Then run in the shell:
fab list_files
It will prompt for an server address:
No hosts found. Please specify (single) host string for connection: irfan#raspberry.lan
A quick note: You can also assign a username and a host right in a fab command:
fab list_files -U irfan -H raspberry.lan
Or you could put a host into the env.hosts variable in your fabfile. Here's how to do it.
Then you'll be prompted for a SSH password:
[irfan#raspberry.lan] run: ls -l
[irfan#raspberry.lan] Login password for 'irfan':
And then the command will be ran successfully.
[irfan#raspberry.lan] out: total 84
[irfan#raspberry.lan] out: drwxr-xr-x 2 root root 4096 Feb 9 05:54 bin
[irfan#raspberry.lan] out: drwxr-xr-x 3 root root 4096 Dec 19 08:19 boot
...
Simple example from here:
import subprocess
import sys
HOST="www.example.org"
# Ports are handled in ~/.ssh/config since we use OpenSSH
COMMAND="uname -a"
ssh = subprocess.Popen(["ssh", "%s" % HOST, COMMAND],
shell=False,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
result = ssh.stdout.readlines()
if result == []:
error = ssh.stderr.readlines()
print >>sys.stderr, "ERROR: %s" % error
else:
print result
It does exactly what you want: connects over ssh, executes command, returns output. No third party library needed.
You may use below method with linux/ Unix 's built in ssh command.
import os
os.system('ssh username#ip bash < local_script.sh >> /local/path/output.txt 2>&1')
os.system('ssh username#ip python < local_program.py >> /local/path/output.txt 2>&1')
Paramiko module can be used to run multiple commands by invoking shell. Here I created class to invoke ssh shell
class ShellHandler:
def __init__(self, host, user, psw):
logger.debug("Initialising instance of ShellHandler host:{0}".format(host))
try:
self.ssh = paramiko.SSHClient()
self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
self.ssh.connect(host, username=user, password=psw, port=22)
self.channel = self.ssh.invoke_shell()
except:
logger.error("Error Creating ssh connection to {0}".format(host))
logger.error("Exiting ShellHandler")
return
self.psw=psw
self.stdin = self.channel.makefile('wb')
self.stdout = self.channel.makefile('r')
self.host=host
time.sleep(2)
while not self.channel.recv_ready():
time.sleep(2)
self.initialprompt=""
while self.channel.recv_ready():
rl, wl, xl = select.select([ self.stdout.channel ], [ ], [ ], 0.0)
if len(rl) > 0:
tmp = self.stdout.channel.recv(24)
self.initialprompt=self.initialprompt+str(tmp.decode())
def __del__(self):
self.ssh.close()
logger.info("closed connection to {0}".format(self.host))
def execute(self, cmd):
cmd = cmd.strip('\n')
self.stdin.write(cmd + '\n')
#self.stdin.write(self.psw +'\n')
self.stdin.flush()
time.sleep(1)
while not self.stdout.channel.recv_ready():
time.sleep(2)
logger.debug("Waiting for recv_ready")
output=""
while self.channel.recv_ready():
rl, wl, xl = select.select([ self.stdout.channel ], [ ], [ ], 0.0)
if len(rl) > 0:
tmp = self.stdout.channel.recv(24)
output=output+str(tmp.decode())
return output
If creating different shell each time does not matter to you then you can use method as below.
def run_cmd(self,cmd):
try:
cmd=cmd+'\n'
#self.ssh.settimeout(60)
stdin,stdout,stderr=self.ssh.exec_command(cmd)
while not stdout.channel.eof_received:
time.sleep(3)
logger.debug("Waiting for eof_received")
out=""
while stdout.channel.recv_ready():
err=stderr.read()
if err:
print("Error: ",my_hostname, str(err))
return False
out=out+stdout.read()
if out:
return out
except:
error=sys.exc_info()
logger.error(error)
return False
I have tried with subprocess and sshpass to execute remote command. Here is my code to execute remote command using subprocess..
import subprocess
import sys
HOST="192.168.20.175"
COMMAND="cat /proc/meminfo | grep MemTotal"
ssh = subprocess.Popen(["sshpass", "-p", "unlock123",
"ssh", "%s" % HOST, COMMAND],
shell=False,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
result = ssh.stdout.readlines()
if result == []:
error = ssh.stderr.readlines()
print >>sys.stderr, "ERROR: %s" % error
else:
print result
print "Return Code - %s" % ssh.returncode
However,
returncode returns None
Now I want to run following loop command on remote machine
"echo"; while true; do ps -p 1820 -o %cpu,%mem | grep -v CPU >> /tmp/proc_out.log;
I want to start the command on remote machine and don't want to wait for the command to complete.
Once the command is fired, get the pid of the command
Kill the process after some time whenever required.
Is there any possible solution for this?