# Copyright 2017 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import logging
import os
import time

import common

from autotest_lib.client.bin import utils
from autotest_lib.client.common_lib import error
from autotest_lib.site_utils.lxc import config as lxc_config
from autotest_lib.site_utils.lxc import constants
from autotest_lib.site_utils.lxc import lxc
from autotest_lib.site_utils.lxc import utils as lxc_utils
from autotest_lib.site_utils.lxc.cleanup_if_fail import cleanup_if_fail
from autotest_lib.site_utils.lxc.base_image import BaseImage
from autotest_lib.site_utils.lxc.constants import \
    CONTAINER_POOL_METRICS_PREFIX as METRICS_PREFIX
from autotest_lib.site_utils.lxc.container import Container
from autotest_lib.site_utils.lxc.container_factory import ContainerFactory

try:
    from autotest_lib.utils.frozen_chromite.lib import metrics
    from infra_libs import ts_mon
except ImportError:
    import mock
    metrics = utils.metrics_mock
    ts_mon = mock.Mock()


class ContainerBucket(object):
    """A wrapper class to interact with containers in a specific container path.
    """

    def __init__(self, container_path=constants.DEFAULT_CONTAINER_PATH,
                 base_name=constants.BASE, container_factory=None):
        """Initialize a ContainerBucket.

        @param container_path: Path to the directory used to store containers.
                               Default is set to AUTOSERV/container_path in
                               global config.
        @param base_name: Name of the base container image. Used to initialize a
                          ContainerFactory unless one is provided via the
                          arguments. Defaults to value set via
                          AUTOSERV/container_base_name in global config.
        @param container_factory: A factory for creating Containers.
        """
        self.container_path = os.path.realpath(container_path)
        if container_factory is not None:
            self._factory = container_factory
        else:
            # Pass in the container path so that the bucket is hermetic (i.e. so
            # that if the container path is customized, the base image doesn't
            # fall back to using the default container path).
            try:
                base_image_ok = True
                container = BaseImage(self.container_path, base_name).get()
            except error.ContainerError:
                base_image_ok = False
                raise
            finally:
                metrics.Counter(METRICS_PREFIX + '/base_image',
                                field_spec=[ts_mon.BooleanField('corrupted')]
                                ).increment(
                                    fields={'corrupted': not base_image_ok})
            self._factory = ContainerFactory(
                base_container=container,
                lxc_path=self.container_path)
        self.container_cache = {}


    def get_all(self, force_update=False):
        """Get details of all containers.

        Retrieves all containers owned by the bucket.  Note that this doesn't
        include the base container, or any containers owned by the container
        pool.

        @param force_update: Boolean, ignore cached values if set.

        @return: A dictionary of all containers with detailed attributes,
                 indexed by container name.
        """
        logging.debug("Fetching all extant LXC containers")
        info_collection = lxc.get_container_info(self.container_path)
        if force_update:
            logging.debug("Clearing cached container info")
        containers = {} if force_update else self.container_cache
        for info in info_collection:
            if info["name"] in containers:
                continue
            container = Container.create_from_existing_dir(self.container_path,
                                                           **info)
            # Active containers have an ID.  Zygotes and base containers, don't.
            if container.id is not None:
                containers[container.id] = container
        self.container_cache = containers
        return containers


    def get_container(self, container_id):
        """Get a container with matching name.

        @param container_id: ID of the container.

        @return: A container object with matching name. Returns None if no
                 container matches the given name.
        """
        logging.debug("Fetching LXC container with id %s", container_id)
        if container_id in self.container_cache:
            logging.debug("Found container %s in cache", container_id)
            return self.container_cache[container_id]

        container = self.get_all().get(container_id, None)
        if None == container:
            logging.debug("Could not find container %s", container_id)
        return container


    def exist(self, container_id):
        """Check if a container exists with the given name.

        @param container_id: ID of the container.

        @return: True if the container with the given ID exists, otherwise
                 returns False.
        """
        return self.get_container(container_id) != None


    def destroy_all(self):
        """Destroy all containers, base must be destroyed at the last.
        """
        containers = self.get_all().values()
        for container in sorted(
                containers, key=lambda n: 1 if n.name == constants.BASE else 0):
            key = container.id
            logging.info('Destroy container %s.', container.name)
            container.destroy()
            del self.container_cache[key]

    def scrub_container_location(self, name,
                                 timeout=constants.LXC_SCRUB_TIMEOUT):
        """Destroy a possibly-nonexistent, possibly-malformed container.

        This exists to clean up an unreachable container which may or may not
        exist and is probably but not definitely malformed if it does exist. It
        is accordingly scorched-earth and force-destroys the container with all
        associated snapshots. Also accordingly, this will not raise an
        exception if the destruction fails.

        @param name: ID of the container.
        @param timeout: Seconds to wait for removal.

        @returns: CmdResult object from the shell command
        """
        logging.debug(
            "Force-destroying container %s if it exists, with timeout %s sec",
            name, timeout)
        try:
            result = lxc_utils.destroy(self.container_path,
                                       name,
                                       force=True,
                                       snapshots=True,
                                       ignore_status=True,
                                       timeout=timeout)
        except error.CmdTimeoutError:
            logging.warning("Force-destruction of container %s timed out.",
                            name)
        logging.debug("Force-destruction exit code %s", result.exit_status)
        return result


    @metrics.SecondsTimerDecorator(
        '%s/setup_test_duration' % constants.STATS_KEY)
    @cleanup_if_fail()
    def setup_test(self,
                   container_id,
                   job_id,
                   server_package_url,
                   result_path,
                   control=None,
                   skip_cleanup=False,
                   job_folder=None,
                   dut_name=None):
        """Setup test container for the test job to run.

        The setup includes:
        1. Install autotest_server package from given url.
        2. Copy over local shadow_config.ini.
        3. Mount local site-packages.
        4. Mount test result directory.

        TODO(dshi): Setup also needs to include test control file for autoserv
                    to run in container.

        @param container_id: ID to assign to the test container.
        @param job_id: Job id for the test job to run in the test container.
        @param server_package_url: Url to download autotest_server package.
        @param result_path: Directory to be mounted to container to store test
                            results.
        @param control: Path to the control file to run the test job. Default is
                        set to None.
        @param skip_cleanup: Set to True to skip cleanup, used to troubleshoot
                             container failures.
        @param job_folder: Folder name of the job, e.g., 123-debug_user.
        @param dut_name: Name of the dut to run test, used as the hostname of
                         the container. Default is None.
        @return: A Container object for the test container.

        @raise ContainerError: If container does not exist, or not running.
        """
        start_time = time.time()

        if not os.path.exists(result_path):
            raise error.ContainerError('Result directory does not exist: %s',
                                       result_path)
        result_path = os.path.abspath(result_path)

        # Save control file to result_path temporarily. The reason is that the
        # control file in drone_tmp folder can be deleted during scheduler
        # restart. For test not using SSP, the window between test starts and
        # control file being picked up by the test is very small (< 2 seconds).
        # However, for tests using SSP, it takes around 1 minute before the
        # container is setup. If scheduler is restarted during that period, the
        # control file will be deleted, and the test will fail.
        if control:
            control_file_name = os.path.basename(control)
            safe_control = os.path.join(result_path, control_file_name)
            utils.run('cp %s %s' % (control, safe_control))

        # Create test container from the base container.
        container = self._factory.create_container(container_id)

        # Deploy server side package
        container.install_ssp(server_package_url)

        deploy_config_manager = lxc_config.DeployConfigManager(container)
        deploy_config_manager.deploy_pre_start()

        # Copy over control file to run the test job.
        if control:
            container.install_control_file(safe_control)

        # Use a pre-packaged Trusty-compatible Autotest site_packages
        # instead if it exists.  crbug.com/1013241
        if os.path.exists(constants.TRUSTY_SITE_PACKAGES_PATH):
            mount_entries = [(constants.TRUSTY_SITE_PACKAGES_PATH,
                              constants.CONTAINER_SITE_PACKAGES_PATH,
                              True)]
        else:
            mount_entries = [(constants.SITE_PACKAGES_PATH,
                              constants.CONTAINER_SITE_PACKAGES_PATH,
                              True)]
        mount_entries.extend([
                (result_path,
                 os.path.join(constants.RESULT_DIR_FMT % job_folder),
                 False),
        ])

        # Update container config to mount directories.
        for source, destination, readonly in mount_entries:
            container.mount_dir(source, destination, readonly)

        # Update file permissions.
        # TODO(dshi): crbug.com/459344 Skip following action when test container
        # can be unprivileged container.
        autotest_path = os.path.join(
                container.rootfs,
                constants.CONTAINER_AUTOTEST_DIR.lstrip(os.path.sep))
        utils.run('sudo chown -R root "%s"' % autotest_path)
        utils.run('sudo chgrp -R root "%s"' % autotest_path)

        container.start(wait_for_network=True, log_dir=result_path)
        deploy_config_manager.deploy_post_start()

        # Update the hostname of the test container to be `dut-name`.
        # Some TradeFed tests use hostname in test results, which is used to
        # group test results in dashboard. The default container name is set to
        # be the name of the folder, which is unique (as it is composed of job
        # id and timestamp. For better result view, the container's hostname is
        # set to be a string containing the dut hostname.
        if dut_name:
            container.set_hostname(constants.CONTAINER_UTSNAME_FORMAT %
                                   dut_name.replace('.', '-'))

        container.modify_import_order()

        container.verify_autotest_setup(job_folder)

        logging.debug('Test container %s is set up.', container.name)
        return container