CODEWITHSUNDEEP
pythonsshcommand-linepython-requestsparamiko
runnerpaul
runnerpaul

Reputation: 7196

When executing curl in Paramiko, its output is in stderr, not stdout

I've a manual task where I ssh onto a server, cd to a folder and run a curl command to download a file to that folder. I'm now trying to automate this in a Python program. I can use paramiko to ssh to the server and run any commands:

ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(credentials)
ssh_stdin, ssh_stdout, ssh_stderr = ssh.exec_command('cd /path/to/folder/ && sudo curl -H \'X-JFrog-Art-Api:api_key\' -O "https://path/to/download/file.tar.xz"', timeout=600)
print(f'curl ssh_stdout: {ssh_stdout.readlines()}')
print(f'curl ssh_stderr: {ssh_stderr.readlines()}')

The file downloads correctly but the output that I expected in stdout appears in stderr. This is the stderr:

curl ssh_stderr: ['  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current\n', '                                 Dload  Upload   Total   Spent    Left  Speed\n', '\r  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0\r  0     0    0     0    0     0      0      0 --:--:--  0:00:01 --:--:--     0\r  0     0    0     0    0     0      0      0 --:--:--  0:00:02 --:--:--     0
...
0  0:04:36  0:04:35  0:00:01 57.6M\r 99 14.9G   99 14.9G    0     0  55.5M      0  0:04:36  0:04:36 --:--:-- 57.6M\r100 14.9G  100 14.9G    0     0  55.5M      0  0:04:36  0:04:36 --:--:-- 57.8M\n']

This hardly seems like a good way to automate my process. Is there a way to do this with some other library which may be better tailored for such an operation? I'm thinking of something like requests.

Upvotes: 1

Views: 1101

Answers (1)

Martin Prikryl
Martin Prikryl

Reputation: 202272

curl outputs its progress to stderr.

Nothing wrong with your code, nor with Paramiko.

In shell, try:

curl https://www.example.com/ > stdout 2> stderr

Your will see that stdout will contain example.com HTML contents and stderr will contain curl progress output.

Upvotes: 2

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