~andrewjbeach/juju-ci-tools/isolate-autoload

from datetime import datetime, timedelta

import gzip

LOG_BREAKDOWN_SECONDS = 20

dt_format = '%Y-%m-%d %H:%M:%S'

def breakdown_log_by_timeframes(log_file, event_timestamps):

    """event_timestamps is a list of TimingData objects."""

    # for each event break the time span into chunks of x seconds. the result

    # being a list of tuples of start/end timestamps

    all_log_breakdown = dict()

    for event in event_timestamps:

        event_range_breakdown = _chunk_event_range(event)

        breakdown = get_timerange_logs(log_file, event_range_breakdown)

        range_name = _render_ds_string(event.start, event.end)

        all_log_breakdown[range_name] = breakdown

    return all_log_breakdown

def _chunk_event_range(event):

    range_breakdown = []

    range_start = datetime.strptime(event.start, dt_format)

    range_end = datetime.strptime(event.end, dt_format)

    next_step = range_start + timedelta(seconds=LOG_BREAKDOWN_SECONDS)

    if next_step > range_end:

        range_breakdown.append((range_start, range_end))

    else:

        while next_step < range_end:

            range_breakdown.append((range_start, next_step))

            range_start = next_step

            next_step = range_start + timedelta(

                seconds=LOG_BREAKDOWN_SECONDS)

            # Otherwise there will be overlap.

            range_start += timedelta(seconds=1)

            if next_step >= range_end:

                range_breakdown.append((range_start, range_end))

    return range_breakdown

def _render_ds_string(start, end):

        return '{} - {}'.format(start, end)

def get_timerange_logs(log_file, timestamps):

    log_breakdown = dict()

    previous_line = None

    no_content = None

    with gzip.open(log_file, 'rt') as f:

        log_lines = []

        for log_range in timestamps:

            range_end = log_range[1]

            if no_content is not None:

                # Extend the range until we get something in the logs.

                range_start = no_content

                no_content = None

                range_str = '{} - {} (condensed)'.format(

                    range_start.strftime('%T'), range_end.strftime('%T'))

                # Don't reset log_lines as it may contain previous details.

            else:

                log_lines = []

                range_start = log_range[0]

                range_str = '{} - {}'.format(

                    range_start.strftime('%T'), range_end.strftime('%T'))

            if previous_line:

                if log_line_within_start_range(previous_line, range_start):

                    log_lines.append(previous_line)

                previous_line = None

            for line in f:

                if log_line_within_start_range(line, range_start):

                    break

            else:

                # Likely because the log cuts off before the action is

                # considered complete (i.e. teardown).

                print('LOG: failed to find start line.')

                break

            # It it's out of range of the end range then there is nothing for

            # this time period.

            if not log_line_within_end_range(line, range_end):

                previous_line = line

                no_content = range_start

                continue

            log_lines.append(line)

            for line in f:

                if log_line_within_end_range(line, range_end):

                    log_lines.append(line)

                else:

                    previous_line = line

                    break

            log_breakdown[range_str] = log_lines

    return log_breakdown

def log_line_within_start_range(line, range_start):

    datestamp = extract_date_from_line(line)

    try:

        ds = datetime.strptime(datestamp, dt_format)

    except ValueError:

        # Don't want an early entry point to the logging.

        return False

    if ds > range_start or ds == range_start:

        return True

    return False

def log_line_within_end_range(line, range_end):

    datestamp = extract_date_from_line(line)

    try:

        ds = datetime.strptime(datestamp, dt_format)

    except ValueError:

        # Fine to collect this line as the line doesn't start with a date and

        # is thus a continuation or undated message.

        return True

    if ds < range_end or ds == range_end:

        return True

    return False

def extract_date_from_line(line):

    return " ".join(line.split()[0:2])