glances/glances/__init__.py

#
# This file is part of Glances.
#
# SPDX-FileCopyrightText: 2024 Nicolas Hennion <nicolas@nicolargo.com>
#
# SPDX-License-Identifier: LGPL-3.0-only
#
#

"""Init the Glances software."""

# Import system libs
import locale
import platform
import signal
import sys
import tracemalloc

# Global name
# Version should start and end with a numerical char
# See https://packaging.python.org/specifications/core-metadata/#version
# Examples: 1.0.0, 1.0.0rc1, 1.1.0_dev1
__version__ = "4.4.1"
__apiversion__ = '4'
__author__ = 'Nicolas Hennion <nicolas@nicolargo.com>'
__license__ = 'LGPLv3'

# Import psutil
try:
    from psutil import __version__ as psutil_version
except ImportError:
    print('psutil library not found. Glances cannot start.')
    sys.exit(1)

# Import Glances libs
# Note: others Glances libs will be imported optionally
from glances.logger import logger
from glances.main import GlancesMain
from glances.timer import Counter

# Check locale
try:
    locale.setlocale(locale.LC_ALL, '')
except locale.Error:
    print("Warning: Unable to set locale. Expect encoding problems.")

# Check psutil version
psutil_min_version = (5, 3, 0)
psutil_version_info = tuple([int(num) for num in psutil_version.split('.')])
if psutil_version_info < psutil_min_version:
    print('psutil 5.3.0 or higher is needed. Glances cannot start.')
    sys.exit(1)


# Trac malloc is only available on Python 3.4 or higher
def __signal_handler(sig, frame):
    logger.debug(f"Signal {sig} caught")
    # Avoid Glances hang when killing process with muliple CTRL-C See #3264
    signal.signal(signal.SIGINT, signal.SIG_IGN)
    end()


def end():
    """Stop Glances."""
    try:
        mode.end()
    except (NameError, KeyError):
        # NameError: name 'mode' is not defined in case of interrupt shortly...
        # ...after starting the server mode (issue #1175)
        pass

    logger.info("Glances stopped gracefully")

    # The end...
    sys.exit(0)


def start_main_loop(args, start_duration):
    logger.debug(f"Glances started in {start_duration.get()} seconds")
    if args.stop_after:
        logger.info(f'Glances will be stopped in ~{args.stop_after * args.time} seconds')


def check_memleak(args, mode):
    if args.memory_leak:
        wait = args.stop_after * args.time * args.memory_leak * 2
        print(f'Memory leak detection, please wait ~{wait} seconds...')
        # First run without dump to fill the memory
        mode.serve_n(args.stop_after)
        # Then start the memory-leak loop
        snapshot_begin = tracemalloc.take_snapshot()
    else:
        snapshot_begin = None

    return snapshot_begin


def setup_server_mode(args, mode):
    if args.stdout_issue or args.stdout_api_restful_doc or args.stdout_api_doc:
        # Serve once for issue and API documentation modes
        mode.serve_issue()
    else:
        # Serve forever
        mode.serve_forever()


def maybe_trace_memleak(args, snapshot_begin):
    if args.trace_malloc or args.memory_leak:
        snapshot_end = tracemalloc.take_snapshot()
    if args.memory_leak:
        snapshot_diff = snapshot_end.compare_to(snapshot_begin, 'filename')
        memory_leak = sum([s.size_diff for s in snapshot_diff])
        print(f"Memory consumption: {memory_leak / 1000:.1f}KB (see log for details)")
        logger.info("Memory consumption (top 5):")
        for stat in snapshot_diff[:5]:
            logger.info(stat)
    if args.trace_malloc:
        # See more options here: https://docs.python.org/3/library/tracemalloc.html
        top_stats = snapshot_end.statistics("filename")
        print("[ Trace malloc - Top 10 ]")
        for stat in top_stats[:10]:
            print(stat)


def start(config, args):
    """Start Glances."""

    # Load mode
    global mode

    if args.trace_malloc or args.memory_leak:
        tracemalloc.start()

    start_duration = Counter()

    if core.is_standalone():
        from glances.standalone import GlancesStandalone as GlancesMode
    elif core.is_client():
        if core.is_client_browser():
            from glances.client_browser import GlancesClientBrowser as GlancesMode
        else:
            from glances.client import GlancesClient as GlancesMode
    elif core.is_server():
        from glances.server import GlancesServer as GlancesMode
    elif core.is_webserver():
        from glances.webserver import GlancesWebServer as GlancesMode

    # Init the mode
    logger.info(f"Start {GlancesMode.__name__} mode")
    mode = GlancesMode(config=config, args=args)

    start_main_loop(args, start_duration)
    snapshot_begin = check_memleak(args, mode)
    setup_server_mode(args, mode)
    maybe_trace_memleak(args, snapshot_begin)

    # Shutdown
    mode.end()


def main():
    """Main entry point for Glances.

    Select the mode (standalone, client or server)
    Run it...
    """
    # SIGHUP not available on Windows (see issue #2408)
    if sys.platform.startswith('win'):
        signal_list = (signal.SIGTERM, signal.SIGINT)
    else:
        signal_list = (signal.SIGTERM, signal.SIGINT, signal.SIGHUP)
    # Catch the kill signal
    for sig in signal_list:
        signal.signal(sig, __signal_handler)

    # Log Glances and psutil version
    logger.info(f'Start Glances {__version__}')
    python_impl = platform.python_implementation()
    python_ver = platform.python_version()
    logger.info(f'{python_impl} {python_ver} ({sys.executable}) and psutil {psutil_version} detected')

    # Share global var
    global core

    # Create the Glances main instance
    # Glances options from the command line are read first (in __init__)
    # then the options from the config file (in parse_args)
    core = GlancesMain()

    # Glances can be ran in standalone, client or server mode
    start(config=core.get_config(), args=core.get_args())