ad/molodetz/services/base.py

# retoor <retoor@molodetz.nl>
import asyncio
import json
import logging
from collections import deque
from datetime import datetime, timedelta, timezone

from molodetz.database import (
    ensure_service_state,
    get_service_state,
    get_setting,
    now_iso,
    parse_iso,
    set_setting,
    write_service_state,
)

logger = logging.getLogger(__name__)

HEARTBEAT_SECONDS = 8
LIVENESS_SECONDS = 15
METRICS_SECONDS = 15
FIELD_TYPES = ("int", "str", "url", "text", "password", "bool", "select")


class ConfigField:
    def __init__(self, key, type="str", default="", label="", help="", minimum=None, maximum=None, options=None, secret=False, group="Algemeen"):
        if type not in FIELD_TYPES:
            raise ValueError(f"unknown field type {type}")
        self.key = key
        self.type = type
        self.default = default
        self.label = label or key
        self.help = help
        self.minimum = minimum
        self.maximum = maximum
        self.options = options or []
        self.secret = secret or type == "password"
        self.group = group

    def coerce(self, raw):
        value = "" if raw is None else str(raw).strip()
        if self.type == "int":
            number = int(value)
            if self.minimum is not None and number < self.minimum:
                raise ValueError(f"{self.label} must be at least {self.minimum}")
            if self.maximum is not None and number > self.maximum:
                raise ValueError(f"{self.label} must be at most {self.maximum}")
            return str(number)
        if self.type == "bool":
            if value not in ("0", "1"):
                raise ValueError(f"{self.label} must be 0 or 1")
            return value
        if self.type == "select":
            if value not in [str(option) for option in self.options]:
                raise ValueError(f"{self.label} must be one of {self.options}")
            return value
        if self.type == "url" and value and not value.startswith(("http://", "https://")):
            raise ValueError(f"{self.label} must be an http(s) URL")
        return value

    def read(self, service_name):
        raw = get_setting(f"service_{service_name}_{self.key}", str(self.default))
        try:
            return self.coerce(raw)
        except (TypeError, ValueError):
            return str(self.default)

    def spec(self, service_name):
        value = self.read(service_name)
        return {
            "key": self.key,
            "type": self.type,
            "label": self.label,
            "help": self.help,
            "group": self.group,
            "options": self.options,
            "minimum": self.minimum,
            "maximum": self.maximum,
            "secret": self.secret,
            "value": "" if self.secret and value else value,
            "has_value": bool(value),
        }


class BaseService:
    name = "base"
    title = "Service"
    description = ""
    default_enabled = True
    default_interval = 60
    min_interval = 1
    config_fields: list[ConfigField] = []
    metrics_interval = METRICS_SECONDS

    def __init__(self):
        self.logs = deque(maxlen=self.log_size())
        self._task = None
        self._row_id = None
        self._last_heartbeat = 0.0
        self._last_metrics = 0.0
        self._last_command = None
        self._was_enabled = None
        self._next_run = None

    @property
    def interval_key(self):
        return f"service_{self.name}_interval"

    def fields(self):
        framework = [
            ConfigField("enabled", "bool", "1" if self.default_enabled else "0", "Ingeschakeld", group="Algemeen"),
            ConfigField("interval", "int", self.default_interval, "Interval (s)", minimum=self.min_interval, group="Algemeen"),
        ]
        tail = [ConfigField("log_size", "int", 200, "Logregels", minimum=10, maximum=5000, group="Logs")]
        return framework + list(self.config_fields) + tail

    def field(self, key):
        for field in self.fields():
            if field.key == key:
                return field
        raise KeyError(key)

    def get_config(self):
        return {field.key: field.read(self.name) for field in self.fields()}

    def is_enabled(self):
        return self.field("enabled").read(self.name) == "1"

    def current_interval(self):
        return max(self.min_interval, int(self.field("interval").read(self.name)))

    def log_size(self):
        try:
            return max(10, int(get_setting(f"service_{self.name}_log_size", "200")))
        except ValueError:
            return 200

    def log(self, message):
        line = f"{datetime.now(timezone.utc).strftime('%d/%m/%Y %H:%M:%S')} {message}"
        self.logs.append(line)
        logger.info("[%s] %s", self.name, message)

    async def run_once(self):
        raise NotImplementedError

    async def on_enable(self):
        return None

    async def on_disable(self):
        return None

    def collect_metrics(self):
        return {"cards": [], "table": None}

    def _command(self):
        return get_setting(f"service_{self.name}_command", "")

    def _persist(self, status, force_metrics=False):
        loop_time = asyncio.get_running_loop().time()
        fields = {"status": status, "heartbeat": now_iso(), "logs": list(self.logs)}
        if self._next_run:
            fields["next_run"] = self._next_run.isoformat()
        if force_metrics or loop_time - self._last_metrics >= self.metrics_interval:
            fields["metrics"] = self.collect_metrics()
            self._last_metrics = loop_time
        write_service_state(self._row_id, **fields)
        self._last_heartbeat = loop_time

    async def _tick(self):
        enabled = self.is_enabled()
        if enabled != self._was_enabled:
            if enabled:
                write_service_state(self._row_id, started_at=now_iso())
                await self.on_enable()
                self.log("ingeschakeld")
            elif self._was_enabled is not None:
                await self.on_disable()
                self.log("uitgeschakeld")
            self._was_enabled = enabled
            self._persist("running" if enabled else "stopped", force_metrics=True)
        command = self._command()
        run_now = False
        if command and command != self._last_command:
            if self._last_command is not None:
                verb = command.split(":", 1)[0]
                if verb == "run":
                    run_now = True
                elif verb == "clear":
                    self.logs.clear()
            self._last_command = command
        if self.logs.maxlen != self.log_size():
            self.logs = deque(self.logs, maxlen=self.log_size())
        now = datetime.now(timezone.utc)
        if enabled and (run_now or self._next_run is None or now >= self._next_run):
            try:
                await self.run_once()
            except Exception as exc:
                self.log(f"fout: {exc}")
                logger.exception("service %s failed", self.name)
            self._next_run = datetime.now(timezone.utc) + timedelta(seconds=self.current_interval())
            write_service_state(self._row_id, last_run=now_iso())
            self._persist("running", force_metrics=True)
        elif asyncio.get_running_loop().time() - self._last_heartbeat >= HEARTBEAT_SECONDS:
            self._persist("running" if enabled else "stopped")

    async def loop(self):
        self._row_id = ensure_service_state(self.name)
        self._last_command = None
        while True:
            try:
                await self._tick()
            except asyncio.CancelledError:
                raise
            except Exception:
                logger.exception("service loop %s crashed a tick", self.name)
            await asyncio.sleep(1)

    def start(self):
        if self._task is None or self._task.done():
            self._task = asyncio.get_running_loop().create_task(self.loop())

    async def stop(self):
        if self._task is not None:
            self._task.cancel()
            try:
                await self._task
            except asyncio.CancelledError:
                pass
            self._task = None
        if self._row_id is not None:
            write_service_state(self._row_id, status="stopped")


def derived_status(service, row):
    if not service.is_enabled():
        return "stopped"
    if row is None:
        return "stalled"
    heartbeat = parse_iso(row.get("heartbeat"))
    if heartbeat and (datetime.now(timezone.utc) - heartbeat).total_seconds() <= LIVENESS_SECONDS:
        return "running"
    return "stalled"


class ServiceManager:
    def __init__(self):
        self.services = {}
        self.supervising = False

    def register(self, service):
        self.services[service.name] = service
        return service

    def get(self, name):
        return self.services.get(name)

    def describe(self, service):
        row = get_service_state(service.name)
        metrics = {}
        logs = []
        if row:
            try:
                metrics = json.loads(row.get("metrics") or "{}")
            except ValueError:
                metrics = {}
            try:
                logs = json.loads(row.get("logs") or "[]")
            except ValueError:
                logs = []
        return {
            "name": service.name,
            "title": service.title,
            "description": service.description,
            "status": derived_status(service, row),
            "enabled": service.is_enabled(),
            "last_run": row.get("last_run") if row else None,
            "next_run": row.get("next_run") if row else None,
            "heartbeat": row.get("heartbeat") if row else None,
            "metrics": metrics,
            "logs": logs,
            "fields": [field.spec(service.name) for field in service.fields()],
        }

    def describe_all(self):
        return [self.describe(service) for service in self.services.values()]

    def set_enabled(self, name, enabled):
        set_setting(f"service_{name}_enabled", "1" if enabled else "0")

    def send_command(self, name, verb):
        current = get_setting(f"service_{name}_command", "")
        counter = 0
        if ":" in current:
            try:
                counter = int(current.split(":", 1)[1])
            except ValueError:
                counter = 0
        set_setting(f"service_{name}_command", f"{verb}:{counter + 1}")

    def save_config(self, name, values):
        service = self.services[name]
        updates = {}
        for field in service.fields():
            if field.key not in values:
                continue
            raw = values[field.key]
            if field.secret and (raw is None or str(raw).strip() == ""):
                continue
            updates[field.key] = field.coerce(raw)
        for key, value in updates.items():
            set_setting(f"service_{name}_{key}", value)
        return updates

    def supervise(self):
        self.supervising = True
        for service in self.services.values():
            service.start()

    async def shutdown_all(self):
        for service in self.services.values():
            await service.stop()
        self.supervising = False


manager = ServiceManager()