#!/usr/bin/env python2
#
# Docker controlling module
#
# Copyright (c) 2016 Red Hat Inc.
#
# Authors:
# Fam Zheng <famz@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2
# or (at your option) any later version. See the COPYING file in
# the top-level directory.
import os
import sys
import subprocess
import json
import hashlib
import atexit
import uuid
import argparse
import tempfile
from shutil import copy
def _text_checksum(text):
"""Calculate a digest string unique to the text content"""
return hashlib.sha1(text).hexdigest()
def _guess_docker_command():
""" Guess a working docker command or raise exception if not found"""
commands = [["docker"], ["sudo", "-n", "docker"]]
for cmd in commands:
if subprocess.call(cmd + ["images"],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE) == 0:
return cmd
commands_txt = "\n".join([" " + " ".join(x) for x in commands])
raise Exception("Cannot find working docker command. Tried:\n%s" % \
commands_txt)
class Docker(object):
""" Running Docker commands """
def __init__(self):
self._command = _guess_docker_command()
self._instances = []
atexit.register(self._kill_instances)
def _do(self, cmd, quiet=True, **kwargs):
if quiet:
kwargs["stdout"] = subprocess.PIPE
return subprocess.call(self._command + cmd, **kwargs)
def _do_kill_instances(self, only_known, only_active=True):
cmd = ["ps", "-q"]
if not only_active:
cmd.append("-a")
for i in self._output(cmd).split():
resp = self._output(["inspect", i])
labels = json.loads(resp)[0]["Config"]["Labels"]
active = json.loads(resp)[0]["State"]["Running"]
if not labels:
continue
instance_uuid = labels.get("com.qemu.instance.uuid", None)
if not instance_uuid:
continue
if only_known and instance_uuid not in self._instances:
continue
print "Terminating", i
if active:
self._do(["kill", i])
self._do(["rm", i])
def clean(self):
self._do_kill_instances(False, False)
return 0
def _kill_instances(self):
return self._do_kill_instances(True)
def _output(self, cmd, **kwargs):
return subprocess.check_output(self._command + cmd,
stderr=subprocess.STDOUT,
**kwargs)
def get_image_dockerfile_checksum(self, tag):
resp = self._output(["inspect", tag])
labels = json.loads(resp)[0]["Config"].get("Labels", {})
return labels.get("com.qemu.dockerfile-checksum", "")
def build_image(self, tag, dockerfile, df_path, quiet=True, argv=None):
if argv == None:
argv = []
tmp_dir = tempfile.mkdtemp(prefix="docker_build")
tmp_df = tempfile.NamedTemporaryFile(dir=tmp_dir, suffix=".docker")
tmp_df.write(dockerfile)
tmp_df.write("\n")
tmp_df.write("LABEL com.qemu.dockerfile-checksum=%s" %
_text_checksum(dockerfile))
tmp_df.flush()
self._do(["build", "-t", tag, "-f", tmp_df.name] + argv + \
[tmp_dir],
quiet=quiet)
def image_matches_dockerfile(self, tag, dockerfile):
try:
checksum = self.get_image_dockerfile_checksum(tag)
except Exception:
return False
return checksum == _text_checksum(dockerfile)
def run(self, cmd, keep, quiet):
label = uuid.uuid1().hex
if not keep:
self._instances.append(label)
ret = self._do(["run", "--label",
"com.qemu.instance.uuid=" + label] + cmd,
quiet=quiet)
if not keep:
self._instances.remove(label)
return ret
class SubCommand(object):
"""A SubCommand template base class"""
name = None # Subcommand name
def shared_args(self, parser):
parser.add_argument("--quiet", action="store_true",
help="Run quietly unless an error occured")
def args(self, parser):
"""Setup argument parser"""
pass
def run(self, args, argv):
"""Run command.
args: parsed argument by argument parser.
argv: remaining arguments from sys.argv.
"""
pass
class RunCommand(SubCommand):
"""Invoke docker run and take care of cleaning up"""
name = "run"
def args(self, parser):
parser.add_argument("--keep", action="store_true",
help="Don't remove image when command completes")
def run(self, args, argv):
return Docker().run(argv, args.keep, quiet=args.quiet)
class BuildCommand(SubCommand):
""" Build docker image out of a dockerfile. Arguments: <tag> <dockerfile>"""
name = "build"
def args(self, parser):
parser.add_argument("tag",
help="Image Tag")
parser.add_argument("dockerfile",
help="Dockerfile name")
def run(self, args, argv):
dockerfile = open(args.dockerfile, "rb").read()
tag = args.tag
dkr = Docker()
if dkr.image_matches_dockerfile(tag, dockerfile):
if not args.quiet:
print "Image is up to date."
return 0
dkr.build_image(tag, dockerfile, args.dockerfile,
quiet=args.quiet, argv=argv)
return 0
class CleanCommand(SubCommand):
"""Clean up docker instances"""
name = "clean"
def run(self, args, argv):
Docker().clean()
return 0
def main():
parser = argparse.ArgumentParser(description="A Docker helper",
usage="%s <subcommand> ..." % os.path.basename(sys.argv[0]))
subparsers = parser.add_subparsers(title="subcommands", help=None)
for cls in SubCommand.__subclasses__():
cmd = cls()
subp = subparsers.add_parser(cmd.name, help=cmd.__doc__)
cmd.shared_args(subp)
cmd.args(subp)
subp.set_defaults(cmdobj=cmd)
args, argv = parser.parse_known_args()
return args.cmdobj.run(args, argv)
if __name__ == "__main__":
sys.exit(main())
