gradio/gradio/queueing.py

from __future__ import annotations

import asyncio
import copy
import json
import os
import random
import time
import traceback
import uuid
from collections import defaultdict
from queue import Queue as ThreadQueue
from typing import TYPE_CHECKING

import fastapi
from gradio_client.utils import ServerMessage
from typing_extensions import Literal

from gradio import route_utils, routes
from gradio.data_classes import (
    Estimation,
    LogMessage,
    PredictBody,
    Progress,
    ProgressUnit,
)
from gradio.exceptions import Error
from gradio.helpers import TrackedIterable
from gradio.utils import LRUCache, run_coro_in_background, safe_get_lock, set_task_name

if TYPE_CHECKING:
    from gradio.blocks import BlockFunction


class Event:
    def __init__(
        self,
        session_hash: str,
        fn_index: int,
        request: fastapi.Request,
        username: str | None,
        concurrency_id: str,
    ):
        self.session_hash = session_hash
        self.fn_index = fn_index
        self.request = request
        self.username = username
        self.concurrency_id = concurrency_id
        self._id = uuid.uuid4().hex
        self.data: PredictBody | None = None
        self.progress: Progress | None = None
        self.progress_pending: bool = False
        self.alive = True


class EventQueue:
    def __init__(self, concurrency_id: str, concurrency_limit: int | None):
        self.queue: list[Event] = []
        self.concurrency_id = concurrency_id
        self.concurrency_limit = concurrency_limit
        self.current_concurrency = 0
        self.start_times_per_fn_index: defaultdict[int, set[float]] = defaultdict(set)


class ProcessTime:
    def __init__(self):
        self.process_time = 0
        self.count = 0
        self.avg_time = 0

    def add(self, time: float):
        self.process_time += time
        self.count += 1
        self.avg_time = self.process_time / self.count


class Queue:
    def __init__(
        self,
        live_updates: bool,
        concurrency_count: int,
        update_intervals: float,
        max_size: int | None,
        block_fns: list[BlockFunction],
        default_concurrency_limit: int | None | Literal["not_set"] = "not_set",
    ):
        self.pending_messages_per_session: LRUCache[str, ThreadQueue] = LRUCache(2000)
        self.pending_event_ids_session: dict[str, set[str]] = {}
        self.pending_message_lock = safe_get_lock()
        self.event_queue_per_concurrency_id: dict[str, EventQueue] = {}
        self.stopped = False
        self.max_thread_count = concurrency_count
        self.update_intervals = update_intervals
        self.active_jobs: list[None | list[Event]] = []
        self.delete_lock = safe_get_lock()
        self.server_app = None
        self.process_time_per_fn_index: defaultdict[int, ProcessTime] = defaultdict(
            ProcessTime
        )
        self.live_updates = live_updates
        self.sleep_when_free = 0.05
        self.progress_update_sleep_when_free = 0.1
        self.max_size = max_size
        self.block_fns = block_fns
        self.continuous_tasks: list[Event] = []
        self._asyncio_tasks: list[asyncio.Task] = []
        self.default_concurrency_limit = self._resolve_concurrency_limit(
            default_concurrency_limit
        )

    def start(self):
        self.active_jobs = [None] * self.max_thread_count
        self.set_event_queue_per_concurrency_id()

        run_coro_in_background(self.start_processing)
        run_coro_in_background(self.start_progress_updates)
        if not self.live_updates:
            run_coro_in_background(self.notify_clients)

    def set_event_queue_per_concurrency_id(self):
        for block_fn in self.block_fns:
            concurrency_id = block_fn.concurrency_id
            concurrency_limit: int | None
            if block_fn.concurrency_limit == "default":
                concurrency_limit = self.default_concurrency_limit
            else:
                concurrency_limit = block_fn.concurrency_limit
            if concurrency_id not in self.event_queue_per_concurrency_id:
                self.event_queue_per_concurrency_id[concurrency_id] = EventQueue(
                    concurrency_id, concurrency_limit
                )
            elif (
                concurrency_limit is not None
            ):  # Update concurrency limit if it is lower than existing limit
                existing_event_queue = self.event_queue_per_concurrency_id[
                    concurrency_id
                ]
                if (
                    existing_event_queue.concurrency_limit is None
                    or concurrency_limit < existing_event_queue.concurrency_limit
                ):
                    existing_event_queue.concurrency_limit = concurrency_limit

    def reload(self):
        self.set_event_queue_per_concurrency_id()

    def close(self):
        self.stopped = True

    def send_message(
        self,
        event: Event,
        message_type: str,
        data: dict | None = None,
    ):
        if not event.alive:
            return
        data = {} if data is None else data
        messages = self.pending_messages_per_session[event.session_hash]
        messages.put_nowait({"msg": message_type, "event_id": event._id, **data})

    def _resolve_concurrency_limit(
        self, default_concurrency_limit: int | None | Literal["not_set"]
    ) -> int | None:
        """
        Handles the logic of resolving the default_concurrency_limit as this can be specified via a combination
        of the `default_concurrency_limit` parameter of the `Blocks.queue()` or the `GRADIO_DEFAULT_CONCURRENCY_LIMIT`
        environment variable. The parameter in `Blocks.queue()` takes precedence over the environment variable.
        Parameters:
            default_concurrency_limit: The default concurrency limit, as specified by a user in `Blocks.queu()`.
        """
        if default_concurrency_limit != "not_set":
            return default_concurrency_limit
        if default_concurrency_limit_env := os.environ.get(
            "GRADIO_DEFAULT_CONCURRENCY_LIMIT"
        ):
            if default_concurrency_limit_env.lower() == "none":
                return None
            else:
                return int(default_concurrency_limit_env)
        else:
            return 1

    def __len__(self):
        total_len = 0
        for event_queue in self.event_queue_per_concurrency_id.values():
            total_len += len(event_queue.queue)
        return total_len

    async def push(
        self, body: PredictBody, request: fastapi.Request, username: str | None
    ) -> tuple[bool, str]:
        if body.session_hash is None:
            return False, "No session hash provided."
        if body.fn_index is None:
            return False, "No function index provided."
        if self.max_size is not None and len(self) >= self.max_size:
            return (
                False,
                f"Queue is full. Max size is {self.max_size} and size is {len(self)}.",
            )

        event = Event(
            body.session_hash,
            body.fn_index,
            request,
            username,
            self.block_fns[body.fn_index].concurrency_id,
        )
        event.data = body
        async with self.pending_message_lock:
            if body.session_hash not in self.pending_messages_per_session:
                self.pending_messages_per_session[body.session_hash] = ThreadQueue()
            if body.session_hash not in self.pending_event_ids_session:
                self.pending_event_ids_session[body.session_hash] = set()
        self.pending_event_ids_session[body.session_hash].add(event._id)
        event_queue = self.event_queue_per_concurrency_id[event.concurrency_id]
        event_queue.queue.append(event)

        self.broadcast_estimations(event.concurrency_id, len(event_queue.queue) - 1)

        return True, event._id

    def _cancel_asyncio_tasks(self):
        for task in self._asyncio_tasks:
            task.cancel()
        self._asyncio_tasks = []

    def set_server_app(self, app: routes.App):
        self.server_app = app

    def get_active_worker_count(self) -> int:
        count = 0
        for worker in self.active_jobs:
            if worker is not None:
                count += 1
        return count

    def get_events(self) -> tuple[list[Event], bool, str] | None:
        concurrency_ids = list(self.event_queue_per_concurrency_id.keys())
        random.shuffle(concurrency_ids)
        for concurrency_id in concurrency_ids:
            event_queue = self.event_queue_per_concurrency_id[concurrency_id]
            if len(event_queue.queue) and (
                event_queue.concurrency_limit is None
                or event_queue.current_concurrency < event_queue.concurrency_limit
            ):
                first_event = event_queue.queue[0]
                block_fn = self.block_fns[first_event.fn_index]
                events = [first_event]
                batch = block_fn.batch
                if batch:
                    events += [
                        event
                        for event in event_queue.queue[1:]
                        if event.fn_index == first_event.fn_index
                    ][: block_fn.max_batch_size - 1]

                for event in events:
                    event_queue.queue.remove(event)

                return events, batch, concurrency_id

    async def start_processing(self) -> None:
        try:
            while not self.stopped:
                if len(self) == 0:
                    await asyncio.sleep(self.sleep_when_free)
                    continue

                if None not in self.active_jobs:
                    await asyncio.sleep(self.sleep_when_free)
                    continue

                # Using mutex to avoid editing a list in use
                async with self.delete_lock:
                    event_batch = self.get_events()

                if event_batch:
                    events, batch, concurrency_id = event_batch
                    self.active_jobs[self.active_jobs.index(None)] = events
                    event_queue = self.event_queue_per_concurrency_id[concurrency_id]
                    event_queue.current_concurrency += 1
                    start_time = time.time()
                    event_queue.start_times_per_fn_index[events[0].fn_index].add(
                        start_time
                    )
                    process_event_task = run_coro_in_background(
                        self.process_events, events, batch, start_time
                    )
                    set_task_name(
                        process_event_task,
                        events[0].session_hash,
                        events[0].fn_index,
                        batch,
                    )

                    self._asyncio_tasks.append(process_event_task)
                    if self.live_updates:
                        self.broadcast_estimations(concurrency_id)
                else:
                    await asyncio.sleep(self.sleep_when_free)
        finally:
            self.stopped = True
            self._cancel_asyncio_tasks()

    async def start_progress_updates(self) -> None:
        """
        Because progress updates can be very frequent, we do not necessarily want to send a message per update.
        Rather, we check for progress updates at regular intervals, and send a message if there is a pending update.
        Consecutive progress updates between sends will overwrite each other so only the most recent update will be sent.
        """
        while not self.stopped:
            events = [
                evt for job in self.active_jobs if job is not None for evt in job
            ] + self.continuous_tasks

            if len(events) == 0:
                await asyncio.sleep(self.progress_update_sleep_when_free)
                continue

            for event in events:
                if event.progress_pending and event.progress:
                    event.progress_pending = False
                    self.send_message(
                        event, ServerMessage.progress, event.progress.model_dump()
                    )

            await asyncio.sleep(self.progress_update_sleep_when_free)

    def set_progress(
        self,
        event_id: str,
        iterables: list[TrackedIterable] | None,
    ):
        if iterables is None:
            return
        for job in self.active_jobs:
            if job is None:
                continue
            for evt in job:
                if evt._id == event_id:
                    progress_data: list[ProgressUnit] = []
                    for iterable in iterables:
                        progress_unit = ProgressUnit(
                            index=iterable.index,
                            length=iterable.length,
                            unit=iterable.unit,
                            progress=iterable.progress,
                            desc=iterable.desc,
                        )
                        progress_data.append(progress_unit)
                    evt.progress = Progress(progress_data=progress_data)
                    evt.progress_pending = True

    def log_message(
        self,
        event_id: str,
        log: str,
        level: Literal["info", "warning"],
    ):
        events = [
            evt for job in self.active_jobs if job is not None for evt in job
        ] + self.continuous_tasks
        for event in events:
            if event._id == event_id:
                log_message = LogMessage(
                    log=log,
                    level=level,
                )
                self.send_message(event, ServerMessage.log, log_message.model_dump())

    async def clean_events(
        self, *, session_hash: str | None = None, event_id: str | None = None
    ) -> None:
        for job_set in self.active_jobs:
            if job_set:
                for job in job_set:
                    if job.session_hash == session_hash or job._id == event_id:
                        job.alive = False

        async with self.delete_lock:
            events_to_remove: list[Event] = []
            for event_queue in self.event_queue_per_concurrency_id.values():
                for event in event_queue.queue:
                    if event.session_hash == session_hash or event._id == event_id:
                        events_to_remove.append(event)

            for event in events_to_remove:
                self.event_queue_per_concurrency_id[event.concurrency_id].queue.remove(
                    event
                )

    async def notify_clients(self) -> None:
        """
        Notify clients about events statuses in the queue periodically.
        """
        while not self.stopped:
            await asyncio.sleep(self.update_intervals)
            if len(self) > 0:
                for concurrency_id in self.event_queue_per_concurrency_id:
                    self.broadcast_estimations(concurrency_id)

    def broadcast_estimations(
        self, concurrency_id: str, after: int | None = None
    ) -> None:
        wait_so_far = 0
        event_queue = self.event_queue_per_concurrency_id[concurrency_id]
        time_till_available_worker: int | None = 0

        if event_queue.current_concurrency == event_queue.concurrency_limit:
            expected_end_times = []
            for fn_index, start_times in event_queue.start_times_per_fn_index.items():
                if fn_index not in self.process_time_per_fn_index:
                    time_till_available_worker = None
                    break
                process_time = self.process_time_per_fn_index[fn_index].avg_time
                expected_end_times += [
                    start_time + process_time for start_time in start_times
                ]
            if time_till_available_worker is not None and len(expected_end_times) > 0:
                time_of_first_completion = min(expected_end_times)
                time_till_available_worker = max(
                    time_of_first_completion - time.time(), 0
                )

        for rank, event in enumerate(event_queue.queue):
            process_time_for_fn = (
                self.process_time_per_fn_index[event.fn_index].avg_time
                if event.fn_index in self.process_time_per_fn_index
                else None
            )
            rank_eta = (
                process_time_for_fn + wait_so_far + time_till_available_worker
                if process_time_for_fn is not None
                and wait_so_far is not None
                and time_till_available_worker is not None
                else None
            )

            if after is None or rank >= after:
                self.send_message(
                    event,
                    ServerMessage.estimation,
                    Estimation(
                        rank=rank, rank_eta=rank_eta, queue_size=len(event_queue.queue)
                    ).model_dump(),
                )
            if event_queue.concurrency_limit is None:
                wait_so_far = 0
            elif wait_so_far is not None and process_time_for_fn is not None:
                wait_so_far += process_time_for_fn / event_queue.concurrency_limit
            else:
                wait_so_far = None

    def get_status(self) -> Estimation:
        return Estimation(
            queue_size=len(self),
        )

    async def call_prediction(self, events: list[Event], batch: bool):
        body = events[0].data
        if body is None:
            raise ValueError("No event data")
        username = events[0].username
        body.event_id = events[0]._id if not batch else None
        try:
            body.request = events[0].request
        except ValueError:
            pass

        if batch:
            body.data = list(zip(*[event.data.data for event in events if event.data]))
            body.request = events[0].request
            body.batched = True

        app = self.server_app
        if app is None:
            raise Exception("Server app has not been set.")
        api_name = "predict"

        fn_index_inferred = route_utils.infer_fn_index(
            app=app, api_name=api_name, body=body
        )

        gr_request = route_utils.compile_gr_request(
            app=app,
            body=body,
            fn_index_inferred=fn_index_inferred,
            username=username,
            request=None,
        )

        try:
            output = await route_utils.call_process_api(
                app=app,
                body=body,
                gr_request=gr_request,
                fn_index_inferred=fn_index_inferred,
            )
        except Exception as error:
            show_error = app.get_blocks().show_error or isinstance(error, Error)
            traceback.print_exc()
            raise Exception(str(error) if show_error else None) from error

        # To emulate the HTTP response from the predict API,
        # convert the output to a JSON response string.
        # This is done by FastAPI automatically in the HTTP endpoint handlers,
        # but we need to do it manually here.
        response_class = app.router.default_response_class
        if isinstance(response_class, fastapi.datastructures.DefaultPlaceholder):
            actual_response_class = response_class.value
        else:
            actual_response_class = response_class
        http_response = actual_response_class(
            output
        )  # Do the same as https://github.com/tiangolo/fastapi/blob/0.87.0/fastapi/routing.py#L264
        # Also, decode the JSON string to a Python object, emulating the HTTP client behavior e.g. the `json()` method of `httpx`.
        response_json = json.loads(http_response.body.decode())

        return response_json

    async def process_events(
        self, events: list[Event], batch: bool, begin_time: float
    ) -> None:
        awake_events: list[Event] = []
        fn_index = events[0].fn_index
        try:
            for event in events:
                if event.alive:
                    self.send_message(
                        event,
                        ServerMessage.process_starts,
                        {
                            "eta": self.process_time_per_fn_index[fn_index].avg_time
                            if fn_index in self.process_time_per_fn_index
                            else None
                        },
                    )
                    awake_events.append(event)
            if not awake_events:
                return
            try:
                response = await self.call_prediction(awake_events, batch)
                err = None
            except Exception as e:
                response = None
                err = e
                for event in awake_events:
                    self.send_message(
                        event,
                        ServerMessage.process_completed,
                        {
                            "output": {
                                "error": None
                                if len(e.args) and e.args[0] is None
                                else str(e)
                            },
                            "success": False,
                        },
                    )
            if response and response.get("is_generating", False):
                old_response = response
                old_err = err
                while response and response.get("is_generating", False):
                    old_response = response
                    old_err = err
                    for event in awake_events:
                        self.send_message(
                            event,
                            ServerMessage.process_generating,
                            {
                                "output": old_response,
                                "success": old_response is not None,
                            },
                        )
                    awake_events = [event for event in awake_events if event.alive]
                    if not awake_events:
                        return
                    try:
                        response = await self.call_prediction(awake_events, batch)
                        err = None
                    except Exception as e:
                        response = None
                        err = e
                for event in awake_events:
                    relevant_response = response or err or old_err
                    self.send_message(
                        event,
                        ServerMessage.process_completed,
                        {
                            "output": {"error": str(relevant_response)}
                            if isinstance(relevant_response, Exception)
                            else relevant_response,
                            "success": relevant_response
                            and not isinstance(relevant_response, Exception),
                        },
                    )
            elif response:
                output = copy.deepcopy(response)
                for e, event in enumerate(awake_events):
                    if batch and "data" in output:
                        output["data"] = list(zip(*response.get("data")))[e]
                    self.send_message(
                        event,
                        ServerMessage.process_completed,
                        {
                            "output": output,
                            "success": response is not None,
                        },
                    )
            end_time = time.time()
            if response is not None:
                self.process_time_per_fn_index[events[0].fn_index].add(
                    end_time - begin_time
                )
        except Exception as e:
            traceback.print_exc()
        finally:
            event_queue = self.event_queue_per_concurrency_id[events[0].concurrency_id]
            event_queue.current_concurrency -= 1
            start_times = event_queue.start_times_per_fn_index[fn_index]
            if begin_time in start_times:
                start_times.remove(begin_time)
            try:
                self.active_jobs[self.active_jobs.index(events)] = None
            except ValueError:
                # `events` can be absent from `self.active_jobs`
                # when this coroutine is called from the `join_queue` endpoint handler in `routes.py`
                # without putting the `events` into `self.active_jobs`.
                # https://github.com/gradio-app/gradio/blob/f09aea34d6bd18c1e2fef80c86ab2476a6d1dd83/gradio/routes.py#L594-L596
                pass
            for event in events:
                # Always reset the state of the iterator
                # If the job finished successfully, this has no effect
                # If the job is cancelled, this will enable future runs
                # to start "from scratch"
                await self.reset_iterators(event._id)

    async def reset_iterators(self, event_id: str):
        # Do the same thing as the /reset route
        app = self.server_app
        if app is None:
            raise Exception("Server app has not been set.")
        if event_id not in app.iterators:
            # Failure, but don't raise an error
            return
        async with app.lock:
            del app.iterators[event_id]
            app.iterators_to_reset.add(event_id)
        return