Commit 9459f754 authored by Marc-André Lureau's avatar Marc-André Lureau
Browse files

docker.py: add podman support 



Add a --engine option to select either docker, podman or auto.

Among other advantages, podman allows to run rootless & daemonless
containers, fortunately sharing compatible CLI with docker.

With current podman, we have to use a uidmap trick in order to be able
to rw-share the ccache directory with the container user.

With a user 1000, the default mapping is:                                                                                                                                                                         1000 (host) -> 0 (container).
So write access to /var/tmp/ccache ends will end with permission
denied error.

With "--uidmap 1000:0:1 --uidmap 0:1:1000", the mapping is:
1000 (host) -> 0 (container, 1st namespace) -> 1000 (container, 2nd namespace).
(the rest is mumbo jumbo to avoid holes in the range of UIDs)

A future podman version may have an option such as --userns-keep-uid.
Thanks to Debarshi Ray <rishi@redhat.com> for the help!

Signed-off-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: default avatarDaniel P. Berrangé <berrange@redhat.com>
parent 2461d80e

tests/docker/docker.py

+43 −5
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ import hashlib 
import atexit

import uuid

import argparse

import enum

import tempfile

import re

import signal
@@ -38,6 +39,26 @@ FILTERED_ENV_NAMES = ['ftp_proxy', 'http_proxy', 'https_proxy'] 


DEVNULL = open(os.devnull, 'wb')



class EngineEnum(enum.IntEnum):

    AUTO = 1

    DOCKER = 2

    PODMAN = 3



    def __str__(self):

        return self.name.lower()



    def __repr__(self):

        return str(self)



    @staticmethod

    def argparse(s):

        try:

            return EngineEnum[s.upper()]

        except KeyError:

            return s





USE_ENGINE = EngineEnum.AUTO



def _text_checksum(text):

    """Calculate a digest string unique to the text content"""
@@ -48,9 +69,14 @@ def _file_checksum(filename): 
    return _text_checksum(open(filename, 'rb').read())





def _guess_docker_command():

    """ Guess a working docker command or raise exception if not found"""

    commands = [["docker"], ["sudo", "-n", "docker"]]

def _guess_engine_command():

    """ Guess a working engine command or raise exception if not found"""

    commands = []



    if USE_ENGINE in [EngineEnum.AUTO, EngineEnum.PODMAN]:

        commands += [["podman"]]

    if USE_ENGINE in [EngineEnum.AUTO, EngineEnum.DOCKER]:

        commands += [["docker"], ["sudo", "-n", "docker"]]

    for cmd in commands:

        try:

            # docker version will return the client details in stdout
@@ -61,7 +87,7 @@ def _guess_docker_command(): 
        except OSError:

            pass

    commands_txt = "\n".join(["  " + " ".join(x) for x in commands])

    raise Exception("Cannot find working docker command. Tried:\n%s" %

    raise Exception("Cannot find working engine command. Tried:\n%s" %

                    commands_txt)
@@ -190,7 +216,7 @@ def _dockerfile_preprocess(df): 
class Docker(object):

    """ Running Docker commands """

    def __init__(self):

        self._command = _guess_docker_command()

        self._command = _guess_engine_command()

        self._instances = []

        atexit.register(self._kill_instances)

        signal.signal(signal.SIGTERM, self._kill_instances)
@@ -340,6 +366,11 @@ class RunCommand(SubCommand): 
        if args.run_as_current_user:

            uid = os.getuid()

            argv = [ "-u", str(uid) ] + argv

            docker = Docker()

            if docker._command[0] == "podman":

                argv = [ "--uidmap", "%d:0:1" % uid,

                         "--uidmap", "0:1:%d" % uid,

                         "--uidmap", "%d:%d:64536" % (uid + 1, uid + 1)] + argv

        return Docker().run(argv, args.keep, quiet=args.quiet)
@@ -507,6 +538,8 @@ class ProbeCommand(SubCommand): 
                print("yes")

            elif docker._command[0] == "sudo":

                print("sudo")

            elif docker._command[0] == "podman":

                print("podman")

        except Exception:

            print("no")
@@ -602,9 +635,13 @@ class CheckCommand(SubCommand): 




def main():

    global USE_ENGINE



    parser = argparse.ArgumentParser(description="A Docker helper",

                                     usage="%s <subcommand> ..." %

                                     os.path.basename(sys.argv[0]))

    parser.add_argument("--engine", type=EngineEnum.argparse, choices=list(EngineEnum),

                        help="specify which container engine to use")

    subparsers = parser.add_subparsers(title="subcommands", help=None)

    for cls in SubCommand.__subclasses__():

        cmd = cls()
@@ -613,6 +650,7 @@ def main(): 
        cmd.args(subp)

        subp.set_defaults(cmdobj=cmd)

    args, argv = parser.parse_known_args()

    USE_ENGINE = args.engine

    return args.cmdobj.run(args, argv)