| #!/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 |
| import re |
| from tarfile import TarFile, TarInfo |
| from StringIO import StringIO |
| from shutil import copy, rmtree |
| |
| |
| DEVNULL = open(os.devnull, 'wb') |
| |
| |
| 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=DEVNULL, stderr=DEVNULL) == 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) |
| |
| 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) |
| |
| 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, infile=None, **kwargs): |
| if quiet: |
| kwargs["stdout"] = DEVNULL |
| if infile: |
| kwargs["stdin"] = infile |
| 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, docker_dir, dockerfile, quiet=True, argv=None): |
| if argv == None: |
| argv = [] |
| |
| tmp_df = tempfile.NamedTemporaryFile(dir=docker_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 + \ |
| [docker_dir], |
| quiet=quiet) |
| |
| def update_image(self, tag, tarball, quiet=True): |
| "Update a tagged image using " |
| |
| self._do(["build", "-t", tag, "-"], quiet=quiet, infile=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) |
| |
| 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 |
| |
| 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("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." |
| 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 |
| |
| # Do we include a extra binary? |
| if args.include_executable: |
| _copy_binary_with_libs(args.include_executable, |
| docker_dir) |
| |
| dkr.build_image(tag, docker_dir, dockerfile, |
| quiet=args.quiet, argv=argv) |
| |
| 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) |
| |
| 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()) |
