diff options
Diffstat (limited to '')
| -rw-r--r-- | synapse/app/generic_worker.py | 2 | ||||
| -rw-r--r-- | synapse/server.py | 7 | ||||
| -rw-r--r-- | synapse/storage/databases/main/__init__.py | 2 | ||||
| -rw-r--r-- | synapse/storage/databases/main/task_scheduler.py | 202 | ||||
| -rw-r--r-- | synapse/storage/schema/__init__.py | 1 | ||||
| -rw-r--r-- | synapse/storage/schema/main/delta/80/02_scheduled_tasks.sql | 28 | ||||
| -rw-r--r-- | synapse/types/__init__.py | 39 | ||||
| -rw-r--r-- | synapse/util/task_scheduler.py | 364 |
8 files changed, 644 insertions, 1 deletions
diff --git a/synapse/app/generic_worker.py b/synapse/app/generic_worker.py index dc79efcc14..d25e3548e0 100644 --- a/synapse/app/generic_worker.py +++ b/synapse/app/generic_worker.py @@ -91,6 +91,7 @@ from synapse.storage.databases.main.state import StateGroupWorkerStore from synapse.storage.databases.main.stats import StatsStore from synapse.storage.databases.main.stream import StreamWorkerStore from synapse.storage.databases.main.tags import TagsWorkerStore +from synapse.storage.databases.main.task_scheduler import TaskSchedulerWorkerStore from synapse.storage.databases.main.transactions import TransactionWorkerStore from synapse.storage.databases.main.ui_auth import UIAuthWorkerStore from synapse.storage.databases.main.user_directory import UserDirectoryStore @@ -144,6 +145,7 @@ class GenericWorkerStore( TransactionWorkerStore, LockStore, SessionStore, + TaskSchedulerWorkerStore, ): # Properties that multiple storage classes define. Tell mypy what the # expected type is. diff --git a/synapse/server.py b/synapse/server.py index e753ff0377..7cdd3ea3c2 100644 --- a/synapse/server.py +++ b/synapse/server.py @@ -142,6 +142,7 @@ from synapse.util.distributor import Distributor from synapse.util.macaroons import MacaroonGenerator from synapse.util.ratelimitutils import FederationRateLimiter from synapse.util.stringutils import random_string +from synapse.util.task_scheduler import TaskScheduler logger = logging.getLogger(__name__) @@ -360,6 +361,7 @@ class HomeServer(metaclass=abc.ABCMeta): """ for i in self.REQUIRED_ON_BACKGROUND_TASK_STARTUP: getattr(self, "get_" + i + "_handler")() + self.get_task_scheduler() def get_reactor(self) -> ISynapseReactor: """ @@ -912,6 +914,9 @@ class HomeServer(metaclass=abc.ABCMeta): """Usage metrics shared between phone home stats and the prometheus exporter.""" return CommonUsageMetricsManager(self) - @cache_in_self def get_worker_locks_handler(self) -> WorkerLocksHandler: return WorkerLocksHandler(self) + + @cache_in_self + def get_task_scheduler(self) -> TaskScheduler: + return TaskScheduler(self) diff --git a/synapse/storage/databases/main/__init__.py b/synapse/storage/databases/main/__init__.py index e17f25e87a..a85633efcd 100644 --- a/synapse/storage/databases/main/__init__.py +++ b/synapse/storage/databases/main/__init__.py @@ -70,6 +70,7 @@ from .state import StateStore from .stats import StatsStore from .stream import StreamWorkerStore from .tags import TagsStore +from .task_scheduler import TaskSchedulerWorkerStore from .transactions import TransactionWorkerStore from .ui_auth import UIAuthStore from .user_directory import UserDirectoryStore @@ -127,6 +128,7 @@ class DataStore( CacheInvalidationWorkerStore, LockStore, SessionStore, + TaskSchedulerWorkerStore, ): def __init__( self, diff --git a/synapse/storage/databases/main/task_scheduler.py b/synapse/storage/databases/main/task_scheduler.py new file mode 100644 index 0000000000..1fb3180c3c --- /dev/null +++ b/synapse/storage/databases/main/task_scheduler.py @@ -0,0 +1,202 @@ +# Copyright 2023 The Matrix.org Foundation C.I.C. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +from typing import TYPE_CHECKING, Any, Dict, List, Optional + +from synapse.storage._base import SQLBaseStore, db_to_json +from synapse.storage.database import ( + DatabasePool, + LoggingDatabaseConnection, + LoggingTransaction, + make_in_list_sql_clause, +) +from synapse.types import JsonDict, JsonMapping, ScheduledTask, TaskStatus +from synapse.util import json_encoder + +if TYPE_CHECKING: + from synapse.server import HomeServer + + +class TaskSchedulerWorkerStore(SQLBaseStore): + def __init__( + self, + database: DatabasePool, + db_conn: LoggingDatabaseConnection, + hs: "HomeServer", + ): + super().__init__(database, db_conn, hs) + + @staticmethod + def _convert_row_to_task(row: Dict[str, Any]) -> ScheduledTask: + row["status"] = TaskStatus(row["status"]) + if row["params"] is not None: + row["params"] = db_to_json(row["params"]) + if row["result"] is not None: + row["result"] = db_to_json(row["result"]) + return ScheduledTask(**row) + + async def get_scheduled_tasks( + self, + *, + actions: Optional[List[str]] = None, + resource_id: Optional[str] = None, + statuses: Optional[List[TaskStatus]] = None, + max_timestamp: Optional[int] = None, + ) -> List[ScheduledTask]: + """Get a list of scheduled tasks from the DB. + + Args: + actions: Limit the returned tasks to those specific action names + resource_id: Limit the returned tasks to the specific resource id, if specified + statuses: Limit the returned tasks to the specific statuses + max_timestamp: Limit the returned tasks to the ones that have + a timestamp inferior to the specified one + + Returns: a list of `ScheduledTask`, ordered by increasing timestamps + """ + + def get_scheduled_tasks_txn(txn: LoggingTransaction) -> List[Dict[str, Any]]: + clauses: List[str] = [] + args: List[Any] = [] + if resource_id: + clauses.append("resource_id = ?") + args.append(resource_id) + if actions is not None: + clause, temp_args = make_in_list_sql_clause( + txn.database_engine, "action", actions + ) + clauses.append(clause) + args.extend(temp_args) + if statuses is not None: + clause, temp_args = make_in_list_sql_clause( + txn.database_engine, "status", statuses + ) + clauses.append(clause) + args.extend(temp_args) + if max_timestamp is not None: + clauses.append("timestamp <= ?") + args.append(max_timestamp) + + sql = "SELECT * FROM scheduled_tasks" + if clauses: + sql = sql + " WHERE " + " AND ".join(clauses) + + sql = sql + "ORDER BY timestamp" + + txn.execute(sql, args) + return self.db_pool.cursor_to_dict(txn) + + rows = await self.db_pool.runInteraction( + "get_scheduled_tasks", get_scheduled_tasks_txn + ) + return [TaskSchedulerWorkerStore._convert_row_to_task(row) for row in rows] + + async def insert_scheduled_task(self, task: ScheduledTask) -> None: + """Insert a specified `ScheduledTask` in the DB. + + Args: + task: the `ScheduledTask` to insert + """ + await self.db_pool.simple_insert( + "scheduled_tasks", + { + "id": task.id, + "action": task.action, + "status": task.status, + "timestamp": task.timestamp, + "resource_id": task.resource_id, + "params": None + if task.params is None + else json_encoder.encode(task.params), + "result": None + if task.result is None + else json_encoder.encode(task.result), + "error": task.error, + }, + desc="insert_scheduled_task", + ) + + async def update_scheduled_task( + self, + id: str, + timestamp: int, + *, + status: Optional[TaskStatus] = None, + result: Optional[JsonMapping] = None, + error: Optional[str] = None, + ) -> bool: + """Update a scheduled task in the DB with some new value(s). + + Args: + id: id of the `ScheduledTask` to update + timestamp: new timestamp of the task + status: new status of the task + result: new result of the task + error: new error of the task + + Returns: `False` if no matching row was found, `True` otherwise + """ + updatevalues: JsonDict = {"timestamp": timestamp} + if status is not None: + updatevalues["status"] = status + if result is not None: + updatevalues["result"] = json_encoder.encode(result) + if error is not None: + updatevalues["error"] = error + nb_rows = await self.db_pool.simple_update( + "scheduled_tasks", + {"id": id}, + updatevalues, + desc="update_scheduled_task", + ) + return nb_rows > 0 + + async def get_scheduled_task(self, id: str) -> Optional[ScheduledTask]: + """Get a specific `ScheduledTask` from its id. + + Args: + id: the id of the task to retrieve + + Returns: the task if available, `None` otherwise + """ + row = await self.db_pool.simple_select_one( + table="scheduled_tasks", + keyvalues={"id": id}, + retcols=( + "id", + "action", + "status", + "timestamp", + "resource_id", + "params", + "result", + "error", + ), + allow_none=True, + desc="get_scheduled_task", + ) + + return TaskSchedulerWorkerStore._convert_row_to_task(row) if row else None + + async def delete_scheduled_task(self, id: str) -> None: + """Delete a specific task from its id. + + Args: + id: the id of the task to delete + """ + await self.db_pool.simple_delete( + "scheduled_tasks", + keyvalues={"id": id}, + desc="delete_scheduled_task", + ) diff --git a/synapse/storage/schema/__init__.py b/synapse/storage/schema/__init__.py index 7de9949a5b..649d3c8e9f 100644 --- a/synapse/storage/schema/__init__.py +++ b/synapse/storage/schema/__init__.py @@ -113,6 +113,7 @@ Changes in SCHEMA_VERSION = 79 Changes in SCHEMA_VERSION = 80 - The event_txn_id_device_id is always written to for new events. + - Add tables for the task scheduler. """ diff --git a/synapse/storage/schema/main/delta/80/02_scheduled_tasks.sql b/synapse/storage/schema/main/delta/80/02_scheduled_tasks.sql new file mode 100644 index 0000000000..286d109ed7 --- /dev/null +++ b/synapse/storage/schema/main/delta/80/02_scheduled_tasks.sql @@ -0,0 +1,28 @@ +/* Copyright 2023 The Matrix.org Foundation C.I.C + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +-- cf ScheduledTask docstring for the meaning of the fields. +CREATE TABLE IF NOT EXISTS scheduled_tasks( + id TEXT PRIMARY KEY, + action TEXT NOT NULL, + status TEXT NOT NULL, + timestamp BIGINT NOT NULL, + resource_id TEXT, + params TEXT, + result TEXT, + error TEXT +); + +CREATE INDEX IF NOT EXISTS scheduled_tasks_status ON scheduled_tasks(status); diff --git a/synapse/types/__init__.py b/synapse/types/__init__.py index 073f682aca..e750417189 100644 --- a/synapse/types/__init__.py +++ b/synapse/types/__init__.py @@ -15,6 +15,7 @@ import abc import re import string +from enum import Enum from typing import ( TYPE_CHECKING, AbstractSet, @@ -969,3 +970,41 @@ class UserProfile(TypedDict): class RetentionPolicy: min_lifetime: Optional[int] = None max_lifetime: Optional[int] = None + + +class TaskStatus(str, Enum): + """Status of a scheduled task""" + + # Task is scheduled but not active + SCHEDULED = "scheduled" + # Task is active and probably running, and if not + # will be run on next scheduler loop run + ACTIVE = "active" + # Task has completed successfully + COMPLETE = "complete" + # Task is over and either returned a failed status, or had an exception + FAILED = "failed" + + +@attr.s(auto_attribs=True, frozen=True, slots=True) +class ScheduledTask: + """Description of a scheduled task""" + + # Id used to identify the task + id: str + # Name of the action to be run by this task + action: str + # Current status of this task + status: TaskStatus + # If the status is SCHEDULED then this represents when it should be launched, + # otherwise it represents the last time this task got a change of state. + # In milliseconds since epoch in system time timezone, usually UTC. + timestamp: int + # Optionally bind a task to some resource id for easy retrieval + resource_id: Optional[str] + # Optional parameters that will be passed to the function ran by the task + params: Optional[JsonMapping] + # Optional result that can be updated by the running task + result: Optional[JsonMapping] + # Optional error that should be assigned a value when the status is FAILED + error: Optional[str] diff --git a/synapse/util/task_scheduler.py b/synapse/util/task_scheduler.py new file mode 100644 index 0000000000..773a8327f6 --- /dev/null +++ b/synapse/util/task_scheduler.py @@ -0,0 +1,364 @@ +# Copyright 2023 The Matrix.org Foundation C.I.C. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +import logging +from typing import TYPE_CHECKING, Awaitable, Callable, Dict, List, Optional, Set, Tuple + +from prometheus_client import Gauge + +from twisted.python.failure import Failure + +from synapse.metrics.background_process_metrics import run_as_background_process +from synapse.types import JsonMapping, ScheduledTask, TaskStatus +from synapse.util.stringutils import random_string + +if TYPE_CHECKING: + from synapse.server import HomeServer + +logger = logging.getLogger(__name__) + + +running_tasks_gauge = Gauge( + "synapse_scheduler_running_tasks", + "The number of concurrent running tasks handled by the TaskScheduler", +) + + +class TaskScheduler: + """ + This is a simple task sheduler aimed at resumable tasks: usually we use `run_in_background` + to launch a background task, or Twisted `deferLater` if we want to do so later on. + + The problem with that is that the tasks will just stop and never be resumed if synapse + is stopped for whatever reason. + + How this works: + - A function mapped to a named action should first be registered with `register_action`. + This function will be called when trying to resuming tasks after a synapse shutdown, + so this registration should happen when synapse is initialised, NOT right before scheduling + a task. + - A task can then be launched using this named action with `schedule_task`. A `params` dict + can be passed, and it will be available to the registered function when launched. This task + can be launch either now-ish, or later on by giving a `timestamp` parameter. + + The function may call `update_task` at any time to update the `result` of the task, + and this can be used to resume the task at a specific point and/or to convey a result to + the code launching the task. + You can also specify the `result` (and/or an `error`) when returning from the function. + + The reconciliation loop runs every 5 mns, so this is not a precise scheduler. When wanting + to launch now, the launch will still not happen before the next loop run. + + Tasks will be run on the worker specified with `run_background_tasks_on` config, + or the main one by default. + There is a limit of 10 concurrent tasks, so tasks may be delayed if the pool is already + full. In this regard, please take great care that scheduled tasks can actually finished. + For now there is no mechanism to stop a running task if it is stuck. + """ + + # Precision of the scheduler, evaluation of tasks to run will only happen + # every `SCHEDULE_INTERVAL_MS` ms + SCHEDULE_INTERVAL_MS = 1 * 60 * 1000 # 1mn + # Time before a complete or failed task is deleted from the DB + KEEP_TASKS_FOR_MS = 7 * 24 * 60 * 60 * 1000 # 1 week + # Maximum number of tasks that can run at the same time + MAX_CONCURRENT_RUNNING_TASKS = 10 + # Time from the last task update after which we will log a warning + LAST_UPDATE_BEFORE_WARNING_MS = 24 * 60 * 60 * 1000 # 24hrs + + def __init__(self, hs: "HomeServer"): + self._store = hs.get_datastores().main + self._clock = hs.get_clock() + self._running_tasks: Set[str] = set() + # A map between action names and their registered function + self._actions: Dict[ + str, + Callable[ + [ScheduledTask, bool], + Awaitable[Tuple[TaskStatus, Optional[JsonMapping], Optional[str]]], + ], + ] = {} + self._run_background_tasks = hs.config.worker.run_background_tasks + + if self._run_background_tasks: + self._clock.looping_call( + run_as_background_process, + TaskScheduler.SCHEDULE_INTERVAL_MS, + "handle_scheduled_tasks", + self._handle_scheduled_tasks, + ) + + def register_action( + self, + function: Callable[ + [ScheduledTask, bool], + Awaitable[Tuple[TaskStatus, Optional[JsonMapping], Optional[str]]], + ], + action_name: str, + ) -> None: + """Register a function to be executed when an action is scheduled with + the specified action name. + + Actions need to be registered as early as possible so that a resumed action + can find its matching function. It's usually better to NOT do that right before + calling `schedule_task` but rather in an `__init__` method. + + Args: + function: The function to be executed for this action. The parameters + passed to the function when launched are the `ScheduledTask` being run, + and a `first_launch` boolean to signal if it's a resumed task or the first + launch of it. The function should return a tuple of new `status`, `result` + and `error` as specified in `ScheduledTask`. + action_name: The name of the action to be associated with the function + """ + self._actions[action_name] = function + + async def schedule_task( + self, + action: str, + *, + resource_id: Optional[str] = None, + timestamp: Optional[int] = None, + params: Optional[JsonMapping] = None, + ) -> str: + """Schedule a new potentially resumable task. A function matching the specified + `action` should have been previously registered with `register_action`. + + Args: + action: the name of a previously registered action + resource_id: a task can be associated with a resource id to facilitate + getting all tasks associated with a specific resource + timestamp: if `None`, the task will be launched as soon as possible, otherwise it + will be launch as soon as possible after the `timestamp` value. + Note that this scheduler is not meant to be precise, and the scheduling + could be delayed if too many tasks are already running + params: a set of parameters that can be easily accessed from inside the + executed function + + Returns: + The id of the scheduled task + """ + if action not in self._actions: + raise Exception( + f"No function associated with action {action} of the scheduled task" + ) + + if timestamp is None or timestamp < self._clock.time_msec(): + timestamp = self._clock.time_msec() + + task = ScheduledTask( + random_string(16), + action, + TaskStatus.SCHEDULED, + timestamp, + resource_id, + params, + result=None, + error=None, + ) + await self._store.insert_scheduled_task(task) + + return task.id + + async def update_task( + self, + id: str, + *, + timestamp: Optional[int] = None, + status: Optional[TaskStatus] = None, + result: Optional[JsonMapping] = None, + error: Optional[str] = None, + ) -> bool: + """Update some task associated values. This is exposed publically so it can + be used inside task functions, mainly to update the result and be able to + resume a task at a specific step after a restart of synapse. + + It can also be used to stage a task, by setting the `status` to `SCHEDULED` with + a new timestamp. + + The `status` can only be set to `ACTIVE` or `SCHEDULED`, `COMPLETE` and `FAILED` + are terminal status and can only be set by returning it in the function. + + Args: + id: the id of the task to update + timestamp: useful to schedule a new stage of the task at a later date + status: the new `TaskStatus` of the task + result: the new result of the task + error: the new error of the task + """ + if status == TaskStatus.COMPLETE or status == TaskStatus.FAILED: + raise Exception( + "update_task can't be called with a FAILED or COMPLETE status" + ) + + if timestamp is None: + timestamp = self._clock.time_msec() + return await self._store.update_scheduled_task( + id, + timestamp, + status=status, + result=result, + error=error, + ) + + async def get_task(self, id: str) -> Optional[ScheduledTask]: + """Get a specific task description by id. + + Args: + id: the id of the task to retrieve + + Returns: + The task information or `None` if it doesn't exist or it has + already been removed because it's too old. + """ + return await self._store.get_scheduled_task(id) + + async def get_tasks( + self, + *, + actions: Optional[List[str]] = None, + resource_id: Optional[str] = None, + statuses: Optional[List[TaskStatus]] = None, + max_timestamp: Optional[int] = None, + ) -> List[ScheduledTask]: + """Get a list of tasks. Returns all the tasks if no args is provided. + + If an arg is `None` all tasks matching the other args will be selected. + If an arg is an empty list, the corresponding value of the task needs + to be `None` to be selected. + + Args: + actions: Limit the returned tasks to those specific action names + resource_id: Limit the returned tasks to the specific resource id, if specified + statuses: Limit the returned tasks to the specific statuses + max_timestamp: Limit the returned tasks to the ones that have + a timestamp inferior to the specified one + + Returns + A list of `ScheduledTask`, ordered by increasing timestamps + """ + return await self._store.get_scheduled_tasks( + actions=actions, + resource_id=resource_id, + statuses=statuses, + max_timestamp=max_timestamp, + ) + + async def delete_task(self, id: str) -> None: + """Delete a task. Running tasks can't be deleted. + + Can only be called from the worker handling the task scheduling. + + Args: + id: id of the task to delete + """ + if self.task_is_running(id): + raise Exception(f"Task {id} is currently running and can't be deleted") + await self._store.delete_scheduled_task(id) + + def task_is_running(self, id: str) -> bool: + """Check if a task is currently running. + + Can only be called from the worker handling the task scheduling. + + Args: + id: id of the task to check + """ + assert self._run_background_tasks + return id in self._running_tasks + + async def _handle_scheduled_tasks(self) -> None: + """Main loop taking care of launching tasks and cleaning up old ones.""" + await self._launch_scheduled_tasks() + await self._clean_scheduled_tasks() + + async def _launch_scheduled_tasks(self) -> None: + """Retrieve and launch scheduled tasks that should be running at that time.""" + for task in await self.get_tasks(statuses=[TaskStatus.ACTIVE]): + if not self.task_is_running(task.id): + if ( + len(self._running_tasks) + < TaskScheduler.MAX_CONCURRENT_RUNNING_TASKS + ): + await self._launch_task(task, first_launch=False) + else: + if ( + self._clock.time_msec() + > task.timestamp + TaskScheduler.LAST_UPDATE_BEFORE_WARNING_MS + ): + logger.warn( + f"Task {task.id} (action {task.action}) has seen no update for more than 24h and may be stuck" + ) + for task in await self.get_tasks( + statuses=[TaskStatus.SCHEDULED], max_timestamp=self._clock.time_msec() + ): + if ( + not self.task_is_running(task.id) + and len(self._running_tasks) + < TaskScheduler.MAX_CONCURRENT_RUNNING_TASKS + ): + await self._launch_task(task, first_launch=True) + + running_tasks_gauge.set(len(self._running_tasks)) + + async def _clean_scheduled_tasks(self) -> None: + """Clean old complete or failed jobs to avoid clutter the DB.""" + for task in await self._store.get_scheduled_tasks( + statuses=[TaskStatus.FAILED, TaskStatus.COMPLETE] + ): + # FAILED and COMPLETE tasks should never be running + assert not self.task_is_running(task.id) + if ( + self._clock.time_msec() + > task.timestamp + TaskScheduler.KEEP_TASKS_FOR_MS + ): + await self._store.delete_scheduled_task(task.id) + + async def _launch_task(self, task: ScheduledTask, first_launch: bool) -> None: + """Launch a scheduled task now. + + Args: + task: the task to launch + first_launch: `True` if it's the first time is launched, `False` otherwise + """ + assert task.action in self._actions + + function = self._actions[task.action] + + async def wrapper() -> None: + try: + (status, result, error) = await function(task, first_launch) + except Exception: + f = Failure() + logger.error( + f"scheduled task {task.id} failed", + exc_info=(f.type, f.value, f.getTracebackObject()), + ) + status = TaskStatus.FAILED + result = None + error = f.getErrorMessage() + + await self._store.update_scheduled_task( + task.id, + self._clock.time_msec(), + status=status, + result=result, + error=error, + ) + self._running_tasks.remove(task.id) + + self._running_tasks.add(task.id) + await self.update_task(task.id, status=TaskStatus.ACTIVE) + description = f"{task.id}-{task.action}" + run_as_background_process(description, wrapper) |