heartbeat/hbd/server/main.py

"""Server runtime: starts UDP listener, HTTP server and websocket stubs."""

import asyncio
import logging
import socket
import time
import signal
import sys
import ssl
from . import __version__

from . import udp
from . import hbdclass

from . import ws as ws_mod
from . import notify as notify_mod
from . import data
from . import users as users_mod

logger = logging.getLogger(__name__)
msg_to_websockets = ws_mod.broadcast
eventlog = notify_mod.eventlog

# shared runtime collections and helpers

def save_state(config, hbdclass):
    """Save current state to pickle file. Safe to call at any time."""
    import pickle
    import os
    from . import users as users_mod

    # Clear timer references before pickling (they can't be serialized)
    for hostname, host in list(hbdclass.Host.hosts.items()):
        for conn_type, conn in host.connections.items():
            if hasattr(conn, 'cancel_overdue_timer'):
                conn.cancel_overdue_timer()
            if hasattr(conn, 'overdue_timer'):
                conn.overdue_timer = None
            if hasattr(conn, 'overdue_callback'):
                conn.overdue_callback = None
            if hasattr(conn, 'timeout_duration'):
                conn.timeout_duration = None

    pickfile = config.get("pickfile", "hbd.pickle")
    tmpfile = pickfile + ".tmp"

    try:
        with open(tmpfile, "wb") as pickf:
            pick = pickle.Pickler(pickf)
            pick.dump(hbdclass.Host.hosts)
            pick.dump(data.msgs)
            pick.dump(users_mod.save_sessions())
        os.replace(tmpfile, pickfile)
    except Exception as e:
        logger.error("Failed to save state: %s", e)
        try:
            os.unlink(tmpfile)
        except Exception:
            pass


def cleanup_function(config, hbdclass):
    """This function will be executed upon program exit."""
    logger.info("Running cleanup function...")
    save_state(config, hbdclass)
    logger.info("Cleanup complete.")


async def reload_configuration(config_obj, config_path, components):
    """Reload configuration and update all components.
    
    Args:
        config_obj: ReloadableConfig instance
        config_path: Path to config file
        components: Dict with threshold_checker and other components
        
    Returns:
        True if reload succeeded, False otherwise
    """
    try:
        logger.info("=" * 60)
        logger.info("Starting configuration reload...")
        logger.info("=" * 60)
        
        # Reload config file
        new_config = await config_obj.reload(config_path)
        
        # Update notify module
        notify_mod.reload_config(new_config)

        # Reload users
        users_mod.load_users(new_config)

        # Re-apply host attributes from updated config to all known hosts
        from . import config as config_mod
        dyndnshosts = config_mod.get_dyndnshosts(new_config)
        watchhosts = config_mod.get_watchhosts(new_config)
        for hostname, host in hbdclass.Host.hosts.items():
            host.dyn = hostname in dyndnshosts
            host.watched = hostname in watchhosts
            access = config_mod.get_host_access(new_config, hostname)
            host.apply_access(access["owner"], access["managers"], access["monitors"])

        # Reload threshold checker and prune alerts orphaned by the new config
        if 'threshold_checker' in components:
            components['threshold_checker'].reload(new_config)
            components['threshold_checker'].purge_stale_alerts(hbdclass)
        
        # Note: Changes to the following require restart:
        # - hb_port, hbd_port, ws_port (already bound)
        # - SSL certificates (already loaded)
        # - pickfile (already opened)
        # - journal settings (journal already initialized)
        
        # These are reloadable and effective immediately:
        # - notification_channels
        # - threshold_configs
        # - hosts (watchhosts, dyndnshosts, notification_channels)
        # - grace period (used on next heartbeat)
        # - debug/verbose flags (used on next message)
        
        logger.info("=" * 60)
        logger.info("Configuration reload completed successfully")
        logger.info("=" * 60)
        return True
        
    except Exception as e:
        logger.error("=" * 60)
        logger.error(f"Failed to reload configuration: {e}", exc_info=True)
        logger.error("Keeping previous configuration")
        logger.error("=" * 60)
        return False


async def _run_async(config, config_path=None):
    from .config import ReloadableConfig
    if not isinstance(config, ReloadableConfig):
        config = ReloadableConfig(config, config_path)

    loop = asyncio.get_running_loop()
    shutdown_event = asyncio.Event()
    reload_event = asyncio.Event()

    # Signal handlers for graceful shutdown and reload
    def signal_handler(signum, frame):
        sig_name = signal.Signals(signum).name if hasattr(signal, "Signals") else signum
        logger.info(f"Received {sig_name}, initiating shutdown...")
        loop.call_soon_threadsafe(shutdown_event.set)
    
    def reload_handler(signum, frame):
        sig_name = signal.Signals(signum).name if hasattr(signal, "Signals") else signum
        logger.info(f"Received {sig_name}, initiating config reload...")
        loop.call_soon_threadsafe(reload_event.set)

    # Register signal handlers
    loop.add_signal_handler(signal.SIGINT, signal_handler, signal.SIGINT, None)
    loop.add_signal_handler(signal.SIGTERM, signal_handler, signal.SIGTERM, None)
    loop.add_signal_handler(signal.SIGHUP, reload_handler, signal.SIGHUP, None)

    from . import http as http_mod
    from . import dns as dns_mod
    from . import notify as notify_mod
    from . import journal as journal_mod
    from . import threshold as threshold_mod

    notify_mod.setup(config, loop=loop)
    
    # Initialize message journal
    msg_journal = journal_mod.get_journal(config)
    await msg_journal.initialize()
    
    # Initialize threshold checker
    threshold_checker = threshold_mod.ThresholdChecker(
        config=config,
        renotify_interval=config.get("threshold_renotify_interval", 3600),
        journal=msg_journal,
    )
    logger.info("Threshold checker initialized")
    
    # Components dict for reload orchestration
    components = {
        'threshold_checker': threshold_checker,
        'msg_journal': msg_journal,
    }

    sock = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
    # Disable IPV6_V6ONLY option to enable dual-stack (listen on IPv4 as well)
    # This option is system-dependent; on many systems, setting it to False enables
    # the socket to handle both IPv4 and IPv6 traffic.
    try:
        sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, False)
    except OSError as e:
        logger.warning(
            f"Warning: Could not reset IPV6_V6ONLY not supported or dual-stack is unavailable. Error: {e}"
        )

    bind_addr = ("::", config.get("hb_port", 50003))
    sock.bind(bind_addr)
    logger.info("Starting UDP server on %s:%s", *bind_addr)

    # Try to enable kernel receive timestamps (Linux SO_TIMESTAMP).
    # If supported, read datagrams via recvmsg() so RTT uses the kernel
    # timestamp rather than the time.time() call after asyncio scheduling.
    use_kernel_ts = udp.enable_kernel_timestamps(sock)
    if use_kernel_ts:
        logger.info("SO_TIMESTAMP enabled: using kernel receive timestamps for RTT")
    else:
        logger.info("SO_TIMESTAMP not available: using time.time() for RTT")

    def udp_handler(msg, addr, transport, recv_ts=None):
        ctx = dict(
            config=config,
            hbdclass=hbdclass,
            msg_to_websockets=msg_to_websockets,
            msg_journal=msg_journal,
            threshold_checker=threshold_checker,
            DEBUG=config.get("debug", 0),
            verbose=config.get("verbose", False),
            recv_ts=recv_ts,
        )
        udp.handle_datagram(msg, addr, transport, ctx)

    if use_kernel_ts:
        # recvmsg path: manage the socket ourselves with loop.add_reader()
        sock.setblocking(False)
        transport = udp.RecvmsgTransport(loop, sock)
        reader = udp.make_recvmsg_reader(sock, udp_handler, transport)
        loop.add_reader(sock.fileno(), reader)
        protocol = None
    else:
        transport, protocol = await loop.create_datagram_endpoint(
            lambda: udp.EchoServerProtocol(config=config, handler=udp_handler),
            sock=sock,
        )

    # Restore connection timers for hosts loaded from pickle
    restore_ctx = dict(
        config=config,
        hbdclass=hbdclass,
        msg_to_websockets=msg_to_websockets,
        threshold_checker=threshold_checker,
    )
    udp.restore_connection_timers(hbdclass, restore_ctx)

    # Drop alert states that no longer have a matching threshold (stale after
    # upgrade or config change between runs).
    threshold_checker.purge_stale_alerts(hbdclass)

    # HTTP server (asyncio-based via aiohttp)
    try:
        http_task = asyncio.create_task(
            http_mod.start(
                host=config.get("hbd_host", ""),
                port=config.get("hbd_port", 50004),
                config=config,
                hbdclass=hbdclass,
                tcss=None,
                verbose=config.get("verbose", False),
                get_now=lambda: time.time(),
                VER="",
            )
        )
        logger.info(
            "HTTP server started on %s:%s",
            config.get("hbd_host", ""),
            config.get("hbd_port", 50004),
        )
    except Exception as e:
        logger.exception("failed to start HTTP server: %s", e)

    # start dns update worker (async)
    dns_task = None
    try:
        dns_task = dns_mod.start_dns_worker(
            hbdclass, config, log=eventlog, loop=loop
        )
        logger.info("dns update worker started")
    except Exception as e:
        logger.exception("dns worker failed to start: %s", e)

    # Register WebSocket state — connections are now served through /ws on the HTTP port
    ws_task = None
    ws_mod.setup(
        loop=loop,
        get_hosts=lambda: [
            hbdclass.Host.hosts[h].stateinfo()
            for h in sorted(hbdclass.Host.hosts)
        ],
        verbose=config.get("verbose", False),
    )
    logger.info("WebSocket handler registered on /ws (HTTP port %s)", config.get("hbd_port", 50004))

    # Periodic autosave task
    autosave_interval = config.get("autosave_interval", 300)  # default: 5 minutes

    async def autosave_task():
        while True:
            await asyncio.sleep(autosave_interval)
            logger.debug("Autosaving state...")
            save_state(config, hbdclass)
            logger.debug("Autosave complete (%d hosts)", len(hbdclass.Host.hosts))

    autosave = asyncio.create_task(autosave_task())
    logger.info("Autosave task started (interval: %ds)", autosave_interval)

    # Main event loop - monitor shutdown and reload events
    try:
        while True:
            # Wait for either shutdown or reload event
            done, pending = await asyncio.wait(
                [
                    asyncio.create_task(shutdown_event.wait()),
                    asyncio.create_task(reload_event.wait()),
                ],
                return_when=asyncio.FIRST_COMPLETED
            )
            
            # Check which event was triggered
            if shutdown_event.is_set():
                logger.info("Shutdown signal received, stopping services...")
                # Cancel pending wait tasks
                for task in pending:
                    task.cancel()
                break
            
            if reload_event.is_set():
                # Clear the event for next reload
                reload_event.clear()
                
                # Cancel pending wait tasks
                for task in pending:
                    task.cancel()
                
                # Perform reload if config_path is available
                if config_path:
                    await reload_configuration(config, config_path, components)
                else:
                    logger.warning("Cannot reload: no config path available")
                
                # Continue main loop
                continue
                
    except Exception as e:
        logger.exception("Error in main loop: %s", e)
    finally:
        # Cancel all running tasks
        logger.info("Cancelling tasks...")
        try:
            transport.close()
        except Exception as e:
            logger.warning("Error closing UDP transport: %s", e)

        tasks_to_cancel = [http_task, autosave]
        for task in tasks_to_cancel:
            if task:
                try:
                    task.cancel()
                    logger.debug("Cancelled task: %s", task)
                except Exception as e:
                    logger.warning("Error cancelling task: %s", e)

        # Wait for tasks to finish cancellation with timeout
        remaining_tasks = [t for t in tasks_to_cancel if t]
        if remaining_tasks:
            try:
                await asyncio.wait_for(
                    asyncio.gather(*remaining_tasks, return_exceptions=True),
                    timeout=2.0,
                )
            except asyncio.TimeoutError:
                logger.warning("Timeout waiting for tasks to cancel")
            except Exception as e:
                logger.debug("Exception during task cancellation: %s", e)
        
        # Close message journal
        try:
            await msg_journal.close()
        except Exception as e:
            logger.warning("Error closing message journal: %s", e)

        # Signal DNS worker to exit and await it
        try:
            if "dns_task" in locals() and dns_task:
                try:
                    hbdclass.Host.dnsQ.put(None)
                except Exception:
                    pass
                try:
                    await asyncio.wait_for(dns_task, timeout=2.0)
                    logger.info("DNS worker finished")
                except asyncio.TimeoutError:
                    logger.warning("Timeout waiting for DNS worker to finish")
                    dns_task.cancel()
                except asyncio.CancelledError:
                    logger.info("DNS worker was cancelled")
                except Exception as e:
                    logger.warning("Error awaiting DNS worker: %s", e)
                finally:
                    # Clear queue bridge to release any held references
                    hbdclass.Host.dnsQ = None
        except Exception as e:
            logger.warning("Error stopping DNS worker: %s", e)

        # Save state (hosts + sessions) on clean shutdown
        try:
            save_state(config, hbdclass)
            logger.info("State saved on shutdown")
        except Exception as e:
            logger.warning("Error saving state on shutdown: %s", e)

        logger.info("All tasks cancelled")


def load_pickled_hosts(config, hbdclass):
    """Load pickled hosts from file, if available."""
    import os
    import pickle
    from . import config as config_mod
    from . import users as users_mod

    pickfile = config.get("pickfile", "hbd.pickle")
    dyndnshosts = config_mod.get_dyndnshosts(config)
    watchhosts = config_mod.get_watchhosts(config)
    drophosts = config.get("drophosts", [])
    if 1 and os.path.exists(pickfile):
        if config.get("verbose", False):
            logger.info("opening pickls %s", pickfile)
        pickf = open(pickfile, "rb")
        pick = pickle.Unpickler(pickf)
        try:
            hbdclass.Host.hosts = pick.load()
            data.msgs = pick.load()
            try:
                users_mod.load_sessions(pick.load())
            except Exception:
                pass  # older pickle without sessions — fine
            pickf.close()
        except Exception as e:
            logger.exception("load pickled failed: %s", e)
            os.unlink(pickfile)
        hbdclass.Connection.htab = {}
        for h in list(hbdclass.Host.hosts.keys()):
            hbdclass.Host.hosts[h].dyn = h in dyndnshosts
            hbdclass.Host.hosts[h].watched = h in watchhosts
            hbdclass.Host.hosts[h].fixup()
            access = config_mod.get_host_access(config, h)
            hbdclass.Host.hosts[h].apply_access(
                access["owner"], access["managers"], access["monitors"]
            )
        for h in drophosts:
            if h in hbdclass.Host.hosts:
                del hbdclass.Host.hosts[h]
        if config.get("verbose", False):
            logger.info("%s pickled hosts loaded", len(hbdclass.Host.hosts))
    else:
        if config.get("verbose", False):
            logger.info("no pickled data")


def run(config, config_path=None):
    """Start the hbd service (blocking).

    Manually manages the event loop to ensure clean shutdown.
    
    Args:
        config: Configuration dictionary
        config_path: Path to config file (for reload support)
    """
    import os

    log_level = logging.WARNING
    if config.get("verbose", False):
        log_level = logging.INFO
    if config.get("debug", 0) > 0:
        log_level = logging.DEBUG
    logging.basicConfig(level=log_level)
    load_pickled_hosts(config, hbdclass)

    notify_mod.initlog(logfile=config.get("logfile", "messages.log"))
    users_mod.load_users(config)

    # Write pidfile
    pidfile = config.get("pidfile", "")
    if pidfile:
        try:
            with open(pidfile, "w") as f:
                f.write(str(os.getpid()))
        except Exception as e:
            logger.warning("Failed to write pidfile %s: %s", pidfile, e)

    eventlog(None, "INFO", f"hbd version {__version__} starting up")
    
    if config_path:
        logger.info(f"Config file: {config_path} (reload with SIGHUP)")
    else:
        logger.warning("No config path provided - reload via SIGHUP disabled")

    # Create and set the event loop manually
    loop = asyncio.new_event_loop()
    asyncio.set_event_loop(loop)

    try:
        loop.run_until_complete(_run_async(config, config_path=config_path))
    except KeyboardInterrupt:
        logger.info("Received KeyboardInterrupt, shutting down...")
    except Exception as e:
        logger.exception("Unhandled exception in main: %s", e)
    finally:
        cleanup_function(config, hbdclass)
        logger.info("hbd shutdown complete")
        eventlog(None, "INFO", f"hbd version {__version__} shutdown")
        notify_mod.closelog()
        # Remove pidfile
        if pidfile:
            try:
                os.unlink(pidfile)
            except Exception:
                pass
        # Explicitly close the loop
        try:
            # Cancel all remaining tasks
            pending = asyncio.all_tasks(loop)
            for task in pending:
                task.cancel()
            # Run one more cycle to process cancellations
            if pending:
                loop.run_until_complete(
                    asyncio.gather(*pending, return_exceptions=True)
                )
        except Exception:
            pass
        finally:
            loop.close()

    # Exit
    os._exit(0)