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#!/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.
from __future__ import print_function
import os
import sys
sys.path.append(os.path.join(os.path.dirname(__file__),
'..', '..', 'scripts'))
import argparse
import subprocess
import json
import hashlib
import atexit
import uuid
import tempfile
import re
import signal
from tarfile import TarFile, TarInfo
try:
from StringIO import StringIO
except ImportError:
from io import StringIO
from shutil import copy, rmtree
from pwd import getpwuid
from datetime import datetime,timedelta
FILTERED_ENV_NAMES = ['ftp_proxy', 'http_proxy', 'https_proxy']
DEVNULL = open(os.devnull, 'wb')
def _text_checksum(text):
"""Calculate a digest string unique to the text content"""
return hashlib.sha1(text).hexdigest()
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"]]
for cmd in commands:
try:
# docker version will return the client details in stdout
# but still report a status of 1 if it can't contact the daemon
if subprocess.call(cmd + ["version"],
stdout=DEVNULL, stderr=DEVNULL) == 0:
return cmd
except OSError:
pass
commands_txt = "\n".join([" " + " ".join(x) for x in commands])
raise Exception("Cannot find working docker command. Tried:\n%s" % \
commands_txt)
def _copy_with_mkdir(src, root_dir, sub_path='.'):
"""Copy src into root_dir, creating sub_path as needed."""
dest_dir = os.path.normpath("%s/%s" % (root_dir, sub_path))
try:
os.makedirs(dest_dir)
except OSError:
# we can safely ignore already created directories
pass
dest_file = "%s/%s" % (dest_dir, os.path.basename(src))
copy(src, dest_file)
def _get_so_libs(executable):
"""Return a list of libraries associated with an executable.
The paths may be symbolic links which would need to be resolved to
ensure theright data is copied."""
libs = []
ldd_re = re.compile(r"(/.*/)(\S*)")
try:
ldd_output = subprocess.check_output(["ldd", executable])
for line in ldd_output.split("\n"):
search = ldd_re.search(line)
if search and len(search.groups()) == 2:
so_path = search.groups()[0]
so_lib = search.groups()[1]
libs.append("%s/%s" % (so_path, so_lib))
except subprocess.CalledProcessError:
print("%s had no associated libraries (static build?)" % (executable))
return libs
def _copy_binary_with_libs(src, dest_dir):
"""Copy a binary executable and all its dependant libraries.
This does rely on the host file-system being fairly multi-arch
aware so the file don't clash with the guests layout."""
_copy_with_mkdir(src, dest_dir, "/usr/bin")
libs = _get_so_libs(src)
if libs:
for l in libs:
so_path = os.path.dirname(l)
_copy_with_mkdir(l , dest_dir, so_path)
def _read_qemu_dockerfile(img_name):
# special case for Debian linux-user images
if img_name.startswith("debian") and img_name.endswith("user"):
img_name = "debian-bootstrap"
df = os.path.join(os.path.dirname(__file__), "dockerfiles",
img_name + ".docker")
return open(df, "r").read()
def _dockerfile_preprocess(df):
out = ""
for l in df.splitlines():
if len(l.strip()) == 0 or l.startswith("#"):
continue
from_pref = "FROM qemu:"
if l.startswith(from_pref):
# TODO: Alternatively we could replace this line with "FROM $ID"
# where $ID is the image's hex id obtained with
# $ docker images $IMAGE --format="{{.Id}}"
# but unfortunately that's not supported by RHEL 7.
inlining = _read_qemu_dockerfile(l[len(from_pref):])
out += _dockerfile_preprocess(inlining)
continue
out += l + "\n"
return out
class Docker(object):
""" Running Docker commands """
def __init__(self):
self._command = _guess_docker_command()
self._instances = []
atexit.register(self._kill_instances)
signal.signal(signal.SIGTERM, self._kill_instances)
signal.signal(signal.SIGHUP, self._kill_instances)
def _do(self, cmd, quiet=True, **kwargs):
if quiet:
kwargs["stdout"] = DEVNULL
return subprocess.call(self._command + cmd, **kwargs)
def _do_check(self, cmd, quiet=True, **kwargs):
if quiet:
kwargs["stdout"] = DEVNULL
return subprocess.check_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, *args, **kwargs):
return self._do_kill_instances(True)
def _output(self, cmd, **kwargs):
return subprocess.check_output(self._command + cmd,
stderr=subprocess.STDOUT,
**kwargs)
def inspect_tag(self, tag):
try:
return self._output(["inspect", tag])
except subprocess.CalledProcessError:
return None
def get_image_creation_time(self, info):
return json.loads(info)[0]["Created"]
def get_image_dockerfile_checksum(self, tag):
resp = self.inspect_tag(tag)
labels = json.loads(resp)[0]["Config"].get("Labels", {})
return labels.get("com.qemu.dockerfile-checksum", "")
def build_image(self, tag, docker_dir, dockerfile,
quiet=True, user=False, argv=None, extra_files_cksum=[]):
if argv == None:
argv = []
tmp_df = tempfile.NamedTemporaryFile(dir=docker_dir, suffix=".docker")
tmp_df.write(dockerfile)
if user:
uid = os.getuid()
uname = getpwuid(uid).pw_name
tmp_df.write("\n")
tmp_df.write("RUN id %s 2>/dev/null || useradd -u %d -U %s" %
(uname, uid, uname))
tmp_df.write("\n")
tmp_df.write("LABEL com.qemu.dockerfile-checksum=%s" %
_text_checksum(_dockerfile_preprocess(dockerfile)))
for f, c in extra_files_cksum:
tmp_df.write("LABEL com.qemu.%s-checksum=%s" % (f, c))
tmp_df.flush()
self._do_check(["build", "-t", tag, "-f", tmp_df.name] + argv + \
[docker_dir],
quiet=quiet)
def update_image(self, tag, tarball, quiet=True):
"Update a tagged image using "
self._do_check(["build", "-t", tag, "-"], quiet=quiet, stdin=tarball)
def image_matches_dockerfile(self, tag, dockerfile):
try:
checksum = self.get_image_dockerfile_checksum(tag)
except Exception:
return False
return checksum == _text_checksum(_dockerfile_preprocess(dockerfile))
def run(self, cmd, keep, quiet):
label = uuid.uuid1().hex
if not keep:
self._instances.append(label)
ret = self._do_check(["run", "--label",
"com.qemu.instance.uuid=" + label] + cmd,
quiet=quiet)
if not keep:
self._instances.remove(label)
return ret
def command(self, cmd, argv, quiet):
return self._do([cmd] + argv, quiet=quiet)
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("--include-executable", "-e",
help="""Specify a binary that will be copied to the
container together with all its dependent
libraries""")
parser.add_argument("--extra-files", "-f", nargs='*',
help="""Specify files that will be copied in the
Docker image, fulfilling the ADD directive from the
Dockerfile""")
parser.add_argument("--add-current-user", "-u", dest="user",
action="store_true",
help="Add the current user to image's passwd")
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 "--no-cache" not in argv and \
dkr.image_matches_dockerfile(tag, dockerfile):
if not args.quiet:
print("Image is up to date.")
else:
# Create a docker context directory for the build
docker_dir = tempfile.mkdtemp(prefix="docker_build")
# Is there a .pre file to run in the build context?
docker_pre = os.path.splitext(args.dockerfile)[0]+".pre"
if os.path.exists(docker_pre):
stdout = DEVNULL if args.quiet else None
rc = subprocess.call(os.path.realpath(docker_pre),
cwd=docker_dir, stdout=stdout)
if rc == 3:
print("Skip")
return 0
elif rc != 0:
print("%s exited with code %d" % (docker_pre, rc))
return 1
# Copy any extra files into the Docker context. These can be
# included by the use of the ADD directive in the Dockerfile.
cksum = []
if args.include_executable:
# FIXME: there is no checksum of this executable and the linked
# libraries, once the image built any change of this executable
# or any library won't trigger another build.
_copy_binary_with_libs(args.include_executable, docker_dir)
for filename in args.extra_files or []:
_copy_with_mkdir(filename, docker_dir)
cksum += [(filename, _file_checksum(filename))]
argv += ["--build-arg=" + k.lower() + "=" + v
for k, v in os.environ.iteritems()
if k.lower() in FILTERED_ENV_NAMES]
dkr.build_image(tag, docker_dir, dockerfile,
quiet=args.quiet, user=args.user, argv=argv,
extra_files_cksum=cksum)
rmtree(docker_dir)
return 0
class UpdateCommand(SubCommand):
""" Update a docker image with new executables. Arguments: <tag> <executable>"""
name = "update"
def args(self, parser):
parser.add_argument("tag",
help="Image Tag")
parser.add_argument("executable",
help="Executable to copy")
def run(self, args, argv):
# Create a temporary tarball with our whole build context and
# dockerfile for the update
tmp = tempfile.NamedTemporaryFile(suffix="dckr.tar.gz")
tmp_tar = TarFile(fileobj=tmp, mode='w')
# Add the executable to the tarball
bn = os.path.basename(args.executable)
ff = "/usr/bin/%s" % bn
tmp_tar.add(args.executable, arcname=ff)
# Add any associated libraries
libs = _get_so_libs(args.executable)
if libs:
for l in libs:
tmp_tar.add(os.path.realpath(l), arcname=l)
# Create a Docker buildfile
df = StringIO()
df.write("FROM %s\n" % args.tag)
df.write("ADD . /\n")
df.seek(0)
df_tar = TarInfo(name="Dockerfile")
df_tar.size = len(df.buf)
tmp_tar.addfile(df_tar, fileobj=df)
tmp_tar.close()
# reset the file pointers
tmp.flush()
tmp.seek(0)
# Run the build with our tarball context
dkr = Docker()
dkr.update_image(args.tag, tmp, quiet=args.quiet)
return 0
class CleanCommand(SubCommand):
"""Clean up docker instances"""
name = "clean"
def run(self, args, argv):
Docker().clean()
return 0
class ImagesCommand(SubCommand):
"""Run "docker images" command"""
name = "images"
def run(self, args, argv):
return Docker().command("images", argv, args.quiet)
class ProbeCommand(SubCommand):
"""Probe if we can run docker automatically"""
name = "probe"
def run(self, args, argv):
try:
docker = Docker()
if docker._command[0] == "docker":
print("yes")
elif docker._command[0] == "sudo":
print("sudo")
except Exception:
print("no")
return
class CcCommand(SubCommand):
"""Compile sources with cc in images"""
name = "cc"
def args(self, parser):
parser.add_argument("--image", "-i", required=True,
help="The docker image in which to run cc")
parser.add_argument("--cc", default="cc",
help="The compiler executable to call")
parser.add_argument("--user",
help="The user-id to run under")
parser.add_argument("--source-path", "-s", nargs="*", dest="paths",
help="""Extra paths to (ro) mount into container for
reading sources""")
def run(self, args, argv):
if argv and argv[0] == "--":
argv = argv[1:]
cwd = os.getcwd()
cmd = ["--rm", "-w", cwd,
"-v", "%s:%s:rw" % (cwd, cwd)]
if args.paths:
for p in args.paths:
cmd += ["-v", "%s:%s:ro,z" % (p, p)]
if args.user:
cmd += ["-u", args.user]
cmd += [args.image, args.cc]
cmd += argv
return Docker().command("run", cmd, args.quiet)
class CheckCommand(SubCommand):
"""Check if we need to re-build a docker image out of a dockerfile.
Arguments: <tag> <dockerfile>"""
name = "check"
def args(self, parser):
parser.add_argument("tag",
help="Image Tag")
parser.add_argument("dockerfile", default=None,
help="Dockerfile name", nargs='?')
parser.add_argument("--checktype", choices=["checksum", "age"],
default="checksum", help="check type")
parser.add_argument("--olderthan", default=60, type=int,
help="number of minutes")
def run(self, args, argv):
tag = args.tag
try:
dkr = Docker()
except:
print("Docker not set up")
return 1
info = dkr.inspect_tag(tag)
if info is None:
print("Image does not exist")
return 1
if args.checktype == "checksum":
if not args.dockerfile:
print("Need a dockerfile for tag:%s" % (tag))
return 1
dockerfile = open(args.dockerfile, "rb").read()
if dkr.image_matches_dockerfile(tag, dockerfile):
if not args.quiet:
print("Image is up to date")
return 0
else:
print("Image needs updating")
return 1
elif args.checktype == "age":
timestr = dkr.get_image_creation_time(info).split(".")[0]
created = datetime.strptime(timestr, "%Y-%m-%dT%H:%M:%S")
past = datetime.now() - timedelta(minutes=args.olderthan)
if created < past:
print ("Image created @ %s more than %d minutes old" %
(timestr, args.olderthan))
return 1
else:
if not args.quiet:
print ("Image less than %d minutes old" % (args.olderthan))
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())
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