sshwrapper.py

#!/usr/bin/env python3

import getpass
import os
import sys

from lib import find_executable, get_hostvars, get_var_within, manage_conf_file


def main():
    argv = list(sys.argv[1:])  # Copy

    bastion_user = None
    bastion_host = None
    bastion_port = None
    remote_user = None
    remote_port = 22
    default_configuration_file = "/etc/ovh/bastion/config.yml"

    cmd = argv.pop()
    host = argv.pop()

    # check if bastion_vars are passed as env vars in the playbook
    # may be usefull if the ansible controller manage many bastions
    # example :
    # - hosts: all
    #   gather_facts: false
    #   environment:
    #     BASTION_USER: "{{ bastion_user }}"
    #     BASTION_HOST: "{{ bastion_host }}"
    #     BASTION_PORT: "{{ bastion_port }}"
    #
    # will result as : ... '/bin/sh -c '"'"'BASTION_USER=my_bastion_user BASTION_HOST=my_bastion_host BASTION_PORT=22 /usr/bin/python3 && sleep 0'"'"''
    for i in list(cmd.split(" ")):
        if "bastion_user" in i.lower():
            bastion_user = i.split("=")[1]
        elif "bastion_host" in i.lower():
            bastion_host = i.split("=")[1]
        elif "bastion_port" in i.lower():
            bastion_port = i.split("=")[1]

    # in some cases (AWX in a non containerised environment for instance), the environment is overridden by the job
    # so we are not able to get the BASTION vars
    # if some vars are still undefined, try to load them from a configuration file
    bastion_host, bastion_port, bastion_user = manage_conf_file(
        os.environ.get("BASTION_CONF_FILE", default_configuration_file),
        bastion_host,
        bastion_port,
        bastion_user,
    )

    # lookup on the inventory may take some time, depending on the source, so use it only if not defined elsewhere
    # it seems like some module like template does not send env vars too...
    if not bastion_host or not bastion_port or not bastion_user:
        hostvar = get_hostvars(host)  # dict

        bastion_port = get_var_within(
            hostvar.get("bastion_port", os.environ.get("BASTION_PORT", 22)), hostvar
        )
        bastion_user = get_var_within(
            hostvar.get(
                "bastion_user", os.environ.get("BASTION_USER", getpass.getuser())
            ),
            hostvar,
        )
        bastion_host = get_var_within(
            hostvar.get("bastion_host", os.environ.get("BASTION_HOST")), hostvar
        )

    for i, e in enumerate(argv):

        if e.startswith("User="):
            remote_user = e.split("=")[-1]
            argv[i] = "User={}".format(bastion_user)
        elif e.startswith("Port="):
            remote_port = e.split("=")[-1]
            argv[i] = "Port={}".format(bastion_port)

    # syscall exec
    args = (
        [
            "ssh",
            "-p",
            bastion_port,
            "-q",
            "-o",
            "StrictHostKeyChecking=no",
            "-l",
            bastion_user,
            bastion_host,
            "-T",
        ]
        + argv
        + [
            "--",
            "-q",
            "-T",
            "--never-escape",
            "--user",
            remote_user,
            "--port",
            remote_port,
            host,
            "--",
            cmd,
        ]
    )
    os.execv(
        find_executable("ssh"),  # full path mandatory
        [str(e).strip() for e in args],  # execv() arg 2 must contain only strings
    )


if __name__ == "__main__":
    main()