Running a python script over ssh with paramiko not working as expected

Question

I have a python script on a raspberry that take a picture, when I run it with putty foo.jpg is indeed created.

However when I run it using paramiko foo.jpg is not created, but the script run as expected (it prints 'foo.jpg captured').

class RemoteServer():
    def __init__(self, ip, port, username, password):
        self.ip = ip
        self.port = port
        self.username = username
        self.password = password

class RemoteHelper():
    def __init__(self, paramiko_ssh_object):
        self.ssh = paramiko_ssh_object

    def waitForExecCommandEnd(self, channel, command):
        """
        Block untill the end of a command executed by Paramiko.ssh.exec_command
            -channel : (channel) channel stdout returned by Paramiko.ssh.exec_command
            -command : (string) command to run
        """
        while not channel.exit_status_ready():
            print "Waiting for end of {}".format(command)
            time.sleep(1)

    def runRemoteCommand(self, command):
        """
        Run a command on the remote server via ssh and block until it ends
            -command : (string) command to run
        """
        print "running {}".format(command)
        a, stdout, stderr = self.ssh.exec_command(command)
        self.waitForExecCommandEnd(stdout.channel, command)
        for line in stdout.readlines():
            print line
        for line in stderr.readlines():
            print li

def authentificate(ssh, rpi):
    ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    print "Connection a %s:%s user=%s mdp=XXXXXXXXX" % (rpi.ip, rpi.port, rpi.username)
    ssh.connect(rpi.ip, port=rpi.port, username=rpi.username, password=rpi.password)

rpi = RemoteServer("192.168.1.20", 22, "pi", "raspberry")
ssh = paramiko.SSHClient()
authentificate(ssh, rpi)
remoteHelper = RemoteHelper(ssh)
remoteHelper.runRemoteCommand("sudo python /home/pi/camera/pictaker.py")

And here is the script on the RPI:

#!/usr/bin/env python
# --*-- encoding: utf-8 --*--

from time import sleep
from picamera import PiCamera

#camera conf
camera = PiCamera()
camera.resolution = (2592, 1944)
camera.vflip = True
camera.framerate = 5

#camera warmpup
print "preparing camera"
camera.start_preview()
sleep(2)

#taking pic
camera.capture('foo.jpg')
print "foo.jpg captured"
camera.close()

would it be due to some unix permissions?

Thanks.

Marcin Fabrykowski · Accepted Answer · 2019-01-19 12:05:13Z

2

Try:
1) print(camera.capture('foo.jpg') to see if it return 0
2) try to change 'foo.jpg' to '/tmp/foo.jpg', maybe it capture image but save it to same other path and you don't know where
Edit:
3) you can try, but it's not so trivial as above, run sudo strace -f -o /tmp/strace.out . Then you will see is there any 'permission denied' or something else

edited Jan 19, 2019 at 12:05

answered Jan 19, 2019 at 12:00

Marcin Fabrykowski

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1 Comment

sliders_alpha Over a year ago

foo.jpg was indeed saved elsewhere, using /tmp/foo.jpg solved the problem. (print(camera.capture('foo.jpg') always display 'None', even when it's working)

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