How to check if the created file using Paramiko exec_command exists

Question

I'm trying to open a file which got created as part of the Paramiko exec_command. The file gets created, but when I check if the file exists, it always returns false. How do I check if the file exists and then open the file for reading?

The code written is:

ip = '10.30.2.104'
username = 'root'
password = 'docker'
def checkSSH(ip, username, password, retries=1):
    ssh = SSHClient()
    ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    ssh.load_system_host_keys()
    for x in range(retries):
        try:
            ssh.connect(ip, username=username, password=password, timeout=10)
            return ssh
        except (
        paramiko.BadHostKeyException, paramiko.AuthenticationException, paramiko.SSHException, socket.error) as e:
            print('Exception occured.. {0}'.format(e))
            return False

hdl = checkSSH(ip, username, password)
cmd = 'ls > test.log'
hdl.exec_command(cmd)
a = os.path.exists('/root/test.log')
print(a) >>> if the file exists, this returns true as per the documentation but in this case, it always returns false.

Answer 1

First, you are not waiting for the command to complete.

For that see:
Execute command and wait for it to finish with Python Paramiko

Once the command completes, you can retrieve its exit code using Channel.recv_exit_status():
How can you get the SSH return code using Paramiko?

If it returns 0, you know that everything went fine and no additional check is needed.

---

Anyway, if you want to check, use SFTP (SFTPClient.stat):

sftp = hdl.open_sftp()
try:
    sftp.stat('/root/test.log')
    print("exists")
except Exception as e:
    print("something is wrong: " + e)

---

Though the execution of ls command seems strange to me.

If you want to retrieve the directory listing, use SFTP: SFTPClient.listdir_attr