#!/usr/bin/env python
# Copyright 2014 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.

"""Report whether DUTs are working are broken.

usage: dut_status [-f] [<time options>] hostname ...

By default, reports on the status of the given hosts, to say whether
they're "working" or "broken".  For purposes of this script "broken"
means "the DUT requires manual intervention before it can be used
for further testing", and "working" means "not broken".  The status
determination is based on the history of completed jobs for the DUT;
current activities are not considered.

With the -f option, reports the job history for the DUT, and whether
the DUT was believed working or broken at the end of each job.

To search the DUT's job history, the script must be given a time
range to search over.  The range is specified with up to two of
three options:
  --until/-u DATE/TIME - Specifies an end time for the search
      range.  (default: now)
  --since/-s DATE/TIME - Specifies a start time for the search
      range. (no default)
  --duration/-d HOURS - Specifies the length of the search interval
      in hours. (default: 12 hours)

Any two time options completely specify the time interval.  If only
one option is provided, these defaults are used:
  --until - Use the given end time with the default duration.
  --since - Use the given start time with the default end time.
  --duration - Use the given duration with the default end time.

If no time options are given, use the default end time and duration.

DATE/TIME values are of the form '2014-11-06 17:21:34'.

Examples:
    $ dut_status chromeos2-row4-rack2-host12
    hostname                     S   last checked         URL
    chromeos2-row4-rack2-host12  NO  2014-11-06 15:25:29  http://...

'NO' means the DUT is broken.  That diagnosis is based on a job that
failed:  'last checked' is the time of the failed job, and the URL
points to the job's logs.

    $ dut_status.py -u '2014-11-06 15:30:00' -d 1 -f chromeos2-row4-rack2-host12
    chromeos2-row4-rack2-host12
        2014-11-06 15:25:29  NO http://...
        2014-11-06 14:44:07  -- http://...
        2014-11-06 14:42:56  OK http://...

The times are the start times of the jobs; the URL points to the
job's logs.  The status indicates the working or broken status after
the job:
  'NO' Indicates that the DUT was definitely broken after the job.
  'OK' Indicates that the DUT was likely working after the job.
  '--' Indicates that the job probably didn't change the DUT's
       status.
Typically, logs of the actual failure will be found at the last job
to report 'OK', or the first job to report '--'.

"""


import argparse
import sys
import time

import common
from autotest_lib.frontend import setup_django_environment

from autotest_lib.client.common_lib import global_config
from autotest_lib.client.common_lib import time_utils
from autotest_lib.frontend.afe import models as afe_models


# Values used to describe the diagnosis of a DUT.  These values are
# used to indicate both DUT status after a job or task, and also
# diagnosis of whether the DUT was working at the end of a given
# time interval.
#
# _NO_STATUS:  Used when there are no events recorded in a given
#     time interval.
# _UNKNOWN:  For an individual event, indicates that the DUT status
#     is unchanged from the previous event.  For a time interval,
#     indicates that the DUT's status can't be determined from the
#     DUT's history.
# _WORKING:  Indicates that the DUT was working normally after the
#     event, or at the end of the time interval.
# _BROKEN:  Indicates that the DUT needed manual repair after the
#     event, or at the end of the time interval.
#
_NO_STATUS = 0
_UNKNOWN = 1
_WORKING = 2
_BROKEN = 3

# List of string values to display for the diagnosis values above,
# indexed by those values.
_DIAGNOSIS_IDS = ['??', '--', 'OK', 'NO']


# Default time interval for the --duration option when a value isn't
# specified on the command line.
_DEFAULT_DURATION = 12


def _parse_time(time_string):
    return int(time_utils.date_string_to_epoch_time(time_string))


class JobEvent(object):
    """Information about an event in host history.

    This remembers the relevant data from a single event in host
    history.  An event is any change in DUT state caused by a job
    or special task.  The data captured are the start and end times
    of the event, the URL of logs to the job or task causing the
    event, and a diagnosis of whether the DUT was working or failed
    afterwards.

    This class is an adapter around the database model objects
    describing jobs and special tasks.  This is an abstract
    superclass, with concrete subclasses for `HostQueueEntry` and
    `SpecialTask` objects.

    @property start_time  Time the job or task began execution.
    @property end_time    Time the job or task finished execution.
    @property job_url     URL to the logs for the event's job.
    @property diagnosis   Working status of the DUT after the event.

    """

    get_config_value = global_config.global_config.get_config_value
    _AFE_HOSTNAME = get_config_value('SERVER', 'hostname')
    _LOG_URL_PATTERN = get_config_value('CROS', 'log_url_pattern')

    @classmethod
    def get_log_url(cls, logdir):
        """Return a URL to job results.

        The URL is constructed from a base URL determined by the
        global config, plus the relative path of the job's log
        directory.

        @param logdir Relative path of the results log directory.

        @return A URL to the requested results log.

        """
        return cls._LOG_URL_PATTERN % (cls._AFE_HOSTNAME, logdir)


    def __init__(self, start_time, end_time):
        self.start_time = int(time.mktime(start_time.timetuple()))
        if end_time:
            self.end_time = int(time.mktime(end_time.timetuple()))
        else:
            self.end_time = None


    def __cmp__(self, other):
        """Compare two jobs by their start time.

        This is a standard Python `__cmp__` method to allow sorting
        `JobEvent` objects by their times.

        @param other The `JobEvent` object to compare to `self`.

        """
        return self.start_time - other.start_time


    @property
    def job_url(self):
        """Return the URL for this event's job logs."""
        raise NotImplemented()


    @property
    def diagnosis(self):
        """Return the status of the DUT after this event.

        The diagnosis is interpreted as follows:
          _UNKNOWN - The DUT status was the same before and after
              the event.
          _WORKING - The DUT appeared to be working after the event.
          _BROKEN - The DUT likely required manual intervention
              after the event.

        @return A valid diagnosis value.

        """
        raise NotImplemented()


class SpecialTaskEvent(JobEvent):
    """`JobEvent` adapter for special tasks.

    This class wraps the standard `JobEvent` interface around a row
    in the `afe_special_tasks` table.

    """

    @classmethod
    def get_tasks(cls, host_id, start_time, end_time):
        """Return special tasks for a host in a given time range.

        Return a list of `SpecialTaskEvent` objects representing all
        special task that ran on the given host in the given time
        range.  The list is ordered as it was returned by the query
        (i.e. unordered).

        @param host_id     Database host id of the desired host.
        @param start_time  Start time of the range of interest.
        @param end_time    End time of the range of interest.

        @return A list of `SpecialTaskEvent` objects.

        """
        filter_start = time_utils.epoch_time_to_date_string(start_time)
        filter_end = time_utils.epoch_time_to_date_string(end_time)
        tasks = afe_models.SpecialTask.objects.filter(
                host_id=host_id,
                time_started__gte=filter_start,
                time_started__lte=filter_end,
                is_complete=True)
        return [cls(t) for t in tasks]


    def __init__(self, afetask):
        self._afetask = afetask
        super(SpecialTaskEvent, self).__init__(
                afetask.time_started, afetask.time_finished)


    @property
    def job_url(self):
        logdir = ('hosts/%s/%s-%s' %
                  (self._afetask.host.hostname, self._afetask.id,
                   self._afetask.task.lower()))
        return SpecialTaskEvent.get_log_url(logdir)


    @property
    def diagnosis(self):
        if self._afetask.success:
            return _WORKING
        elif self._afetask.task == 'Repair':
            return _BROKEN
        else:
            return _UNKNOWN


class TestJobEvent(JobEvent):
    """`JobEvent` adapter for regular test jobs.

    This class wraps the standard `JobEvent` interface around a row
    in the `afe_host_queue_entries` table.

    """

    @classmethod
    def get_hqes(cls, host_id, start_time, end_time):
        """Return HQEs for a host in a given time range.

        Return a list of `TestJobEvent` objects representing all the
        HQEs of all the jobs that ran on the given host in the given
        time range.  The list is ordered as it was returned by the
        query (i.e. unordered).

        @param host_id     Database host id of the desired host.
        @param start_time  Start time of the range of interest.
        @param end_time    End time of the range of interest.

        @return A list of `TestJobEvent` objects.

        """
        filter_start = time_utils.epoch_time_to_date_string(start_time)
        filter_end = time_utils.epoch_time_to_date_string(end_time)
        hqelist = afe_models.HostQueueEntry.objects.filter(
                host_id=host_id,
                started_on__gte=filter_start,
                started_on__lte=filter_end,
                complete=True)
        return [cls(hqe) for hqe in hqelist]


    def __init__(self, hqe):
        self._hqe = hqe
        super(TestJobEvent, self).__init__(
                hqe.started_on, hqe.finished_on)


    @property
    def job_url(self):
        logdir = '%s-%s' % (self._hqe.job.id, self._hqe.job.owner)
        return TestJobEvent.get_log_url(logdir)


    @property
    def diagnosis(self):
        if self._hqe.finished_on is not None:
            return _WORKING
        else:
            return _UNKNOWN


class HostJobHistory(object):
    """Class to query and remember DUT execution history.

    This class is responsible for querying the database to determine
    the history of a single DUT in a time interval of interest, and
    for remembering the query results for reporting.

    @property hostname    Host name of the DUT.
    @property start_time  Start of the requested time interval.
    @property end_time    End of the requested time interval.
    @property host        Database host object for the DUT.
    @property history     A list of jobs and special tasks that
                          ran on the DUT in the requested time
                          interval, ordered in reverse, from latest
                          to earliest.

    """

    @classmethod
    def get_history_by_host(cls, hostname, start_time, end_time):
        afehost = afe_models.Host.objects.get(hostname=hostname)
        return cls(afehost, start_time, end_time)


    def __init__(self, afehost, start_time, end_time):
        self.hostname = afehost.hostname
        self.start_time = start_time
        self.end_time = end_time
        self._host = afehost
        self._history = self._get_history(start_time, end_time)


    def __iter__(self):
        return self._history.__iter__()


    def _get_history(self, start_time, end_time):
        newtasks = SpecialTaskEvent.get_tasks(
                self._host.id, start_time, end_time)
        newhqes = TestJobEvent.get_hqes(
                self._host.id, start_time, end_time)
        newhistory = newtasks + newhqes
        newhistory.sort(reverse=True)
        return newhistory


    def last_diagnosis(self):
        """Return the diagnosis of whether the DUT is working.

        This searches the DUT's job history from most to least
        recent, looking for jobs that indicate whether the DUT
        was working.  Return a tuple of `(diagnosis, job)`.

        The `diagnosis` entry in the tuple is one of these values:
          * _NO_STATUS - The job history is empty.
          * _UNKNOWN - All jobs in the history returned _UNKNOWN
              status.
          * _WORKING - The DUT is working.
          * _BROKEN - The DUT likely requires manual intervention.

        The `job` entry in the tuple is the job that led to the
        diagnosis.  The job will be `None` if the diagnosis is
        `_NO_STATUS` or `_UNKNOWN`.

        @return A tuple with the DUT's diagnosis and the job that
                determined it.

        """
        if not self._history:
            return _NO_STATUS, None
        for job in self:
            status = job.diagnosis
            if status != _UNKNOWN:
                return job.diagnosis, job
        return _UNKNOWN, None


def _print_simple_status(history_list):
    fmt = '%-28s %-2s  %-19s  %s'
    print fmt % ('hostname', 'S', 'last checked', 'URL')
    for history in history_list:
        status, event = history.last_diagnosis()
        if event is not None:
            datestr = time_utils.epoch_time_to_date_string(
                    event.start_time)
            url = event.job_url
        else:
            datestr = '---'
            url = '---'
        print fmt % (history.hostname,
                     _DIAGNOSIS_IDS[status],
                     datestr,
                     url)


def _print_host_history(history_list):
    for history in history_list:
        print history.hostname
        for event in history:
            start_time = time_utils.epoch_time_to_date_string(
                    event.start_time)
            print '    %s  %s %s' % (
                    start_time,
                    _DIAGNOSIS_IDS[event.diagnosis],
                    event.job_url)


def _validate_time_range(arguments):
    """Validate the time range requested on the command line.

    Enforces the rules for the --until, --since, and --duration
    options are followed, and calculates defaults:
      * It isn't allowed to supply all three options.
      * If only two options are supplied, they completely determine
        the time interval.
      * If only one option is supplied, or no options, then apply
        specified defaults to the arguments object.

    @param arguments Parsed arguments object as returned by
                     ArgumentParser.parse_args().

    """
    if (arguments.duration is not None and
            arguments.since is not None and arguments.until is not None):
        print >>sys.stderr, ('FATAL: Can specify at most two of '
                             '--since, --until, and --duration')
        sys.exit(1)
    if (arguments.until is None and (arguments.since is None or
                                     arguments.duration is None)):
        arguments.until = int(time.time())
    if arguments.since is None:
        if arguments.duration is None:
            arguments.duration = _DEFAULT_DURATION
        arguments.since = (arguments.until -
                           arguments.duration * 60 * 60)
    elif arguments.until is None:
        arguments.until = (arguments.since +
                           arguments.duration * 60 * 60)


def _validate_host_list(arguments):
    """Validate hostname arguments from the command line.

    Checks that the hosts specified on the command line are valid.
    Invalid hosts generate a warning message, and are omitted from
    futher processing.

    The return value is a list of HostJobHistory objects for to the
    requested valid hostnames, using the time range supplied on the
    command line.

    @param arguments Parsed arguments object as returned by
                     ArgumentParser.parse_args().
    @return List of HostJobHistory objects for the hosts requested
            on the command line.

    """
    histories = []
    saw_error = False
    for hostname in arguments.hostnames:
        try:
            h = HostJobHistory.get_history_by_host(
                    hostname, arguments.since, arguments.until)
            histories.append(h)
        except:
            print >>sys.stderr, ('WARNING: Ignoring unknown host %s' %
                                  hostname)
            saw_error = True
    if saw_error:
        # Create separation from the output that follows
        print >>sys.stderr
    return histories


def _validate_command(arguments):
    """Check that the command's arguments are valid.

    This performs command line checking to enforce command line
    rules that ArgumentParser can't handle.  Additionally, this
    handles calculation of default arguments/options when a simple
    constant default won't do.

    Areas checked:
      * Check that a valid time range was provided, supplying
        defaults as necessary.
      * Identify invalid host names.

    @param arguments Parsed arguments object as returned by
                     ArgumentParser.parse_args().
    @return List of HostJobHistory objects for the hosts requested
            on the command line.

    """
    _validate_time_range(arguments)
    return _validate_host_list(arguments)


def _parse_command(argv):
    """Parse the command line arguments.

    Create an argument parser for this command's syntax, parse the
    command line, and return the result of the ArgumentParser
    parse_args() method.

    @param argv Standard command line argument vector; argv[0] is
                assumed to be the command name.
    @return Result returned by ArgumentParser.parse_args().

    """
    parser = argparse.ArgumentParser(
            prog=argv[0],
            description='Report DUT status and execution history',
            epilog='You can specify one or two of --since, --until, '
                   'and --duration, but not all three.\n'
                   'The date/time format is "YYYY-MM-DD HH:MM:SS".')
    parser.add_argument('-s', '--since', type=_parse_time,
                        metavar='DATE/TIME',
                        help='starting time for history display')
    parser.add_argument('-u', '--until', type=_parse_time,
                        metavar='DATE/TIME',
                        help='ending time for history display'
                             ' (default: now)')
    parser.add_argument('-d', '--duration', type=int,
                        metavar='HOURS',
                        help='number of hours of history to display'
                             ' (default: %d)' % _DEFAULT_DURATION)
    parser.add_argument('-f', '--full_history', action='store_true',
                        help='Display host history from most '
                             'to least recent for each DUT')
    parser.add_argument('hostnames',
                        nargs='+',
                        help='host names of DUTs to report on')
    arguments = parser.parse_args(argv[1:])
    return arguments


def main(argv):
    """Standard main() for command line processing.

    @param argv Command line arguments (normally sys.argv).

    """
    arguments = _parse_command(argv)
    history_list = _validate_command(arguments)
    if arguments.full_history:
        _print_host_history(history_list)
    else:
        _print_simple_status(history_list)


if __name__ == '__main__':
    main(sys.argv)