# Copyright 2013 Quanta Research Cambridge, Inc.
#
#    Licensed under the Apache License, Version 2.0 (the "License");
#    you may not use this file except in compliance with the License.
#    You may obtain a copy of the License at
#
#        http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS,
#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#    See the License for the specific language governing permissions and
#    limitations under the License.

import multiprocessing
import os
import signal
import time

from six import moves

from tempest import auth
from tempest import clients
from tempest.common import ssh
from tempest.common.utils import data_utils
from tempest import config
from tempest import exceptions
from tempest.openstack.common import importutils
from tempest.openstack.common import log as logging
from tempest.stress import cleanup

CONF = config.CONF

LOG = logging.getLogger(__name__)
processes = []


def do_ssh(command, host, ssh_user, ssh_key=None):
    ssh_client = ssh.Client(host, ssh_user, key_filename=ssh_key)
    try:
        return ssh_client.exec_command(command)
    except exceptions.SSHExecCommandFailed:
        LOG.error('do_ssh raise exception. command:%s, host:%s.'
                  % (command, host))
        return None


def _get_compute_nodes(controller, ssh_user, ssh_key=None):
    """
    Returns a list of active compute nodes. List is generated by running
    nova-manage on the controller.
    """
    nodes = []
    cmd = "nova-manage service list | grep ^nova-compute"
    output = do_ssh(cmd, controller, ssh_user, ssh_key)
    if not output:
        return nodes
    # For example: nova-compute xg11eth0 nova enabled :-) 2011-10-31 18:57:46
    # This is fragile but there is, at present, no other way to get this info.
    for line in output.split('\n'):
        words = line.split()
        if len(words) > 0 and words[4] == ":-)":
            nodes.append(words[1])
    return nodes


def _has_error_in_logs(logfiles, nodes, ssh_user, ssh_key=None,
                       stop_on_error=False):
    """
    Detect errors in the nova log files on the controller and compute nodes.
    """
    grep = 'egrep "ERROR|TRACE" %s' % logfiles
    ret = False
    for node in nodes:
        errors = do_ssh(grep, node, ssh_user, ssh_key)
        if len(errors) > 0:
            LOG.error('%s: %s' % (node, errors))
            ret = True
            if stop_on_error:
                break
    return ret


def sigchld_handler(signalnum, frame):
    """
    Signal handler (only active if stop_on_error is True).
    """
    for process in processes:
        if (not process['process'].is_alive() and
                process['process'].exitcode != 0):
            signal.signal(signalnum, signal.SIG_DFL)
            terminate_all_processes()
            break


def terminate_all_processes(check_interval=20):
    """
    Goes through the process list and terminates all child processes.
    """
    LOG.info("Stopping all processes.")
    for process in processes:
        if process['process'].is_alive():
            try:
                process['process'].terminate()
            except Exception:
                pass
    time.sleep(check_interval)
    for process in processes:
        if process['process'].is_alive():
            try:
                pid = process['process'].pid
                LOG.warn("Process %d hangs. Send SIGKILL." % pid)
                os.kill(pid, signal.SIGKILL)
            except Exception:
                pass
        process['process'].join()


def stress_openstack(tests, duration, max_runs=None, stop_on_error=False):
    """
    Workload driver. Executes an action function against a nova-cluster.
    """
    admin_manager = clients.AdminManager()

    ssh_user = CONF.stress.target_ssh_user
    ssh_key = CONF.stress.target_private_key_path
    logfiles = CONF.stress.target_logfiles
    log_check_interval = int(CONF.stress.log_check_interval)
    default_thread_num = int(CONF.stress.default_thread_number_per_action)
    if logfiles:
        controller = CONF.stress.target_controller
        computes = _get_compute_nodes(controller, ssh_user, ssh_key)
        for node in computes:
            do_ssh("rm -f %s" % logfiles, node, ssh_user, ssh_key)
    for test in tests:
        if test.get('use_admin', False):
            manager = admin_manager
        else:
            manager = clients.Manager()
        for p_number in moves.xrange(test.get('threads', default_thread_num)):
            if test.get('use_isolated_tenants', False):
                username = data_utils.rand_name("stress_user")
                tenant_name = data_utils.rand_name("stress_tenant")
                password = "pass"
                identity_client = admin_manager.identity_client
                _, tenant = identity_client.create_tenant(name=tenant_name)
                identity_client.create_user(username,
                                            password,
                                            tenant['id'],
                                            "email")
                creds = auth.get_credentials(username=username,
                                             password=password,
                                             tenant_name=tenant_name)
                manager = clients.Manager(credentials=creds)

            test_obj = importutils.import_class(test['action'])
            test_run = test_obj(manager, max_runs, stop_on_error)

            kwargs = test.get('kwargs', {})
            test_run.setUp(**dict(kwargs.iteritems()))

            LOG.debug("calling Target Object %s" %
                      test_run.__class__.__name__)

            mp_manager = multiprocessing.Manager()
            shared_statistic = mp_manager.dict()
            shared_statistic['runs'] = 0
            shared_statistic['fails'] = 0

            p = multiprocessing.Process(target=test_run.execute,
                                        args=(shared_statistic,))

            process = {'process': p,
                       'p_number': p_number,
                       'action': test_run.action,
                       'statistic': shared_statistic}

            processes.append(process)
            p.start()
    if stop_on_error:
        # NOTE(mkoderer): only the parent should register the handler
        signal.signal(signal.SIGCHLD, sigchld_handler)
    end_time = time.time() + duration
    had_errors = False
    try:
        while True:
            if max_runs is None:
                remaining = end_time - time.time()
                if remaining <= 0:
                    break
            else:
                remaining = log_check_interval
                all_proc_term = True
                for process in processes:
                    if process['process'].is_alive():
                        all_proc_term = False
                        break
                if all_proc_term:
                    break

            time.sleep(min(remaining, log_check_interval))
            if stop_on_error:
                if any([True for proc in processes
                        if proc['statistic']['fails'] > 0]):
                    break

            if not logfiles:
                continue
            if _has_error_in_logs(logfiles, computes, ssh_user, ssh_key,
                                  stop_on_error):
                had_errors = True
                break
    except KeyboardInterrupt:
        LOG.warning("Interrupted, going to print statistics and exit ...")

    if stop_on_error:
        signal.signal(signal.SIGCHLD, signal.SIG_DFL)
    terminate_all_processes()

    sum_fails = 0
    sum_runs = 0

    LOG.info("Statistics (per process):")
    for process in processes:
        if process['statistic']['fails'] > 0:
            had_errors = True
        sum_runs += process['statistic']['runs']
        sum_fails += process['statistic']['fails']
        LOG.info(" Process %d (%s): Run %d actions (%d failed)" %
                 (process['p_number'],
                  process['action'],
                  process['statistic']['runs'],
                     process['statistic']['fails']))
    LOG.info("Summary:")
    LOG.info("Run %d actions (%d failed)" %
             (sum_runs, sum_fails))

    if not had_errors and CONF.stress.full_clean_stack:
        LOG.info("cleaning up")
        cleanup.cleanup()
    if had_errors:
        return 1
    else:
        return 0
