lbry-sdk/lbry/stream/stream_manager.py

import os
import asyncio
import binascii
import logging
import random
import typing
from typing import Optional
from aiohttp.web import Request
from lbry.error import ResolveError, InvalidStreamDescriptorError, DownloadSDTimeoutError, InsufficientFundsError
from lbry.error import ResolveTimeoutError, DownloadDataTimeoutError, KeyFeeAboveMaxAllowedError
from lbry.utils import cache_concurrent
from lbry.stream.descriptor import StreamDescriptor
from lbry.stream.managed_stream import ManagedStream
from lbry.schema.claim import Claim
from lbry.schema.url import URL
from lbry.wallet.dewies import dewies_to_lbc
from lbry.wallet import Output

if typing.TYPE_CHECKING:
    from lbry.conf import Config
    from lbry.blob.blob_manager import BlobManager
    from lbry.dht.node import Node
    from lbry.extras.daemon.analytics import AnalyticsManager
    from lbry.extras.daemon.storage import SQLiteStorage, StoredContentClaim
    from lbry.extras.daemon.exchange_rate_manager import ExchangeRateManager

log = logging.getLogger(__name__)

FILTER_FIELDS = [
    'rowid',
    'status',
    'file_name',
    'added_on',
    'sd_hash',
    'stream_hash',
    'claim_name',
    'claim_height',
    'claim_id',
    'outpoint',
    'txid',
    'nout',
    'channel_claim_id',
    'channel_name',
    'full_status',  # TODO: remove
    'blobs_remaining',
    'blobs_in_stream'
]

COMPARISON_OPERATORS = {
    'eq': lambda a, b: a == b,
    'ne': lambda a, b: a != b,
    'g': lambda a, b: a > b,
    'l': lambda a, b: a < b,
    'ge': lambda a, b: a >= b,
    'le': lambda a, b: a <= b,
}


def path_or_none(path) -> Optional[str]:
    if not path:
        return
    return binascii.unhexlify(path).decode()


class StreamManager:
    def __init__(self, loop: asyncio.AbstractEventLoop, config: 'Config', blob_manager: 'BlobManager',
                 wallet_manager: 'WalletManager', storage: 'SQLiteStorage', node: Optional['Node'],
                 analytics_manager: Optional['AnalyticsManager'] = None):
        self.loop = loop
        self.config = config
        self.blob_manager = blob_manager
        self.wallet_manager = wallet_manager
        self.storage = storage
        self.node = node
        self.analytics_manager = analytics_manager
        self.streams: typing.Dict[str, ManagedStream] = {}
        self.resume_saving_task: Optional[asyncio.Task] = None
        self.re_reflect_task: Optional[asyncio.Task] = None
        self.update_stream_finished_futs: typing.List[asyncio.Future] = []
        self.running_reflector_uploads: typing.List[asyncio.Task] = []
        self.started = asyncio.Event(loop=self.loop)

    async def _update_content_claim(self, stream: ManagedStream):
        claim_info = await self.storage.get_content_claim(stream.stream_hash)
        self.streams.setdefault(stream.sd_hash, stream).set_claim(claim_info, claim_info['value'])

    async def recover_streams(self, file_infos: typing.List[typing.Dict]):
        to_restore = []

        async def recover_stream(sd_hash: str, stream_hash: str, stream_name: str,
                                 suggested_file_name: str, key: str,
                                 content_fee: Optional['Transaction']) -> Optional[StreamDescriptor]:
            sd_blob = self.blob_manager.get_blob(sd_hash)
            blobs = await self.storage.get_blobs_for_stream(stream_hash)
            descriptor = await StreamDescriptor.recover(
                self.blob_manager.blob_dir, sd_blob, stream_hash, stream_name, suggested_file_name, key, blobs
            )
            if not descriptor:
                return
            to_restore.append((descriptor, sd_blob, content_fee))

        await asyncio.gather(*[
            recover_stream(
                file_info['sd_hash'], file_info['stream_hash'], binascii.unhexlify(file_info['stream_name']).decode(),
                binascii.unhexlify(file_info['suggested_file_name']).decode(), file_info['key'],
                file_info['content_fee']
            ) for file_info in file_infos
        ])

        if to_restore:
            await self.storage.recover_streams(to_restore, self.config.download_dir)

        # if self.blob_manager._save_blobs:
        #     log.info("Recovered %i/%i attempted streams", len(to_restore), len(file_infos))

    async def add_stream(self, rowid: int, sd_hash: str, file_name: Optional[str],
                         download_directory: Optional[str], status: str,
                         claim: Optional['StoredContentClaim'], content_fee: Optional['Transaction'],
                         added_on: Optional[int]):
        try:
            descriptor = await self.blob_manager.get_stream_descriptor(sd_hash)
        except InvalidStreamDescriptorError as err:
            log.warning("Failed to start stream for sd %s - %s", sd_hash, str(err))
            return
        stream = ManagedStream(
            self.loop, self.config, self.blob_manager, descriptor.sd_hash, download_directory, file_name, status,
            claim, content_fee=content_fee, rowid=rowid, descriptor=descriptor,
            analytics_manager=self.analytics_manager, added_on=added_on
        )
        self.streams[sd_hash] = stream
        self.storage.content_claim_callbacks[stream.stream_hash] = lambda: self._update_content_claim(stream)

    async def load_and_resume_streams_from_database(self):
        to_recover = []
        to_start = []

        await self.storage.update_manually_removed_files_since_last_run()

        for file_info in await self.storage.get_all_lbry_files():
            # if the sd blob is not verified, try to reconstruct it from the database
            # this could either be because the blob files were deleted manually or save_blobs was not true when
            # the stream was downloaded
            if not self.blob_manager.is_blob_verified(file_info['sd_hash']):
                to_recover.append(file_info)
            to_start.append(file_info)
        if to_recover:
            await self.recover_streams(to_recover)

        log.info("Initializing %i files", len(to_start))
        to_resume_saving = []
        add_stream_tasks = []
        for file_info in to_start:
            file_name = path_or_none(file_info['file_name'])
            download_directory = path_or_none(file_info['download_directory'])
            if file_name and download_directory and not file_info['saved_file'] and file_info['status'] == 'running':
                to_resume_saving.append((file_name, download_directory, file_info['sd_hash']))
            add_stream_tasks.append(self.loop.create_task(self.add_stream(
                file_info['rowid'], file_info['sd_hash'], file_name,
                download_directory, file_info['status'],
                file_info['claim'], file_info['content_fee'],
                file_info['added_on']
            )))
        if add_stream_tasks:
            await asyncio.gather(*add_stream_tasks, loop=self.loop)
        log.info("Started stream manager with %i files", len(self.streams))
        if not self.node:
            log.info("no DHT node given, resuming downloads trusting that we can contact reflector")
        if to_resume_saving:
            self.resume_saving_task = self.loop.create_task(self.resume(to_resume_saving))

    async def resume(self, to_resume_saving):
        log.info("Resuming saving %i files", len(to_resume_saving))
        await asyncio.gather(
            *(self.streams[sd_hash].save_file(file_name, download_directory, node=self.node)
              for (file_name, download_directory, sd_hash) in to_resume_saving),
            loop=self.loop
        )

    async def reflect_streams(self):
        while True:
            if self.config.reflect_streams and self.config.reflector_servers:
                sd_hashes = await self.storage.get_streams_to_re_reflect()
                sd_hashes = [sd for sd in sd_hashes if sd in self.streams]
                batch = []
                while sd_hashes:
                    stream = self.streams[sd_hashes.pop()]
                    if self.blob_manager.is_blob_verified(stream.sd_hash) and stream.blobs_completed:
                        if not stream.fully_reflected.is_set():
                            host, port = random.choice(self.config.reflector_servers)
                            batch.append(stream.upload_to_reflector(host, port))
                    if len(batch) >= self.config.concurrent_reflector_uploads:
                        await asyncio.gather(*batch, loop=self.loop)
                        batch = []
                if batch:
                    await asyncio.gather(*batch, loop=self.loop)
            await asyncio.sleep(300, loop=self.loop)

    async def start(self):
        await self.load_and_resume_streams_from_database()
        self.re_reflect_task = self.loop.create_task(self.reflect_streams())
        self.started.set()

    def stop(self):
        if self.resume_saving_task and not self.resume_saving_task.done():
            self.resume_saving_task.cancel()
        if self.re_reflect_task and not self.re_reflect_task.done():
            self.re_reflect_task.cancel()
        while self.streams:
            _, stream = self.streams.popitem()
            stream.stop_tasks()
        while self.update_stream_finished_futs:
            self.update_stream_finished_futs.pop().cancel()
        while self.running_reflector_uploads:
            self.running_reflector_uploads.pop().cancel()
        self.started.clear()
        log.info("finished stopping the stream manager")

    async def create_stream(self, file_path: str, key: Optional[bytes] = None,
                            iv_generator: Optional[typing.Generator[bytes, None, None]] = None) -> ManagedStream:
        stream = await ManagedStream.create(self.loop, self.config, self.blob_manager, file_path, key, iv_generator)
        self.streams[stream.sd_hash] = stream
        self.storage.content_claim_callbacks[stream.stream_hash] = lambda: self._update_content_claim(stream)
        if self.config.reflect_streams and self.config.reflector_servers:
            host, port = random.choice(self.config.reflector_servers)
            task = self.loop.create_task(stream.upload_to_reflector(host, port))
            self.running_reflector_uploads.append(task)
            task.add_done_callback(
                lambda _: None
                if task not in self.running_reflector_uploads else self.running_reflector_uploads.remove(task)
            )
        return stream

    async def delete_stream(self, stream: ManagedStream, delete_file: Optional[bool] = False):
        stream.stop_tasks()
        if stream.sd_hash in self.streams:
            del self.streams[stream.sd_hash]
        blob_hashes = [stream.sd_hash] + [b.blob_hash for b in stream.descriptor.blobs[:-1]]
        await self.blob_manager.delete_blobs(blob_hashes, delete_from_db=False)
        await self.storage.delete_stream(stream.descriptor)
        if delete_file and stream.output_file_exists:
            os.remove(stream.full_path)

    def get_stream_by_stream_hash(self, stream_hash: str) -> Optional[ManagedStream]:
        streams = tuple(filter(lambda stream: stream.stream_hash == stream_hash, self.streams.values()))
        if streams:
            return streams[0]

    def get_filtered_streams(self, sort_by: Optional[str] = None, reverse: Optional[bool] = False,
                             comparison: Optional[str] = None,
                             **search_by) -> typing.List[ManagedStream]:
        """
        Get a list of filtered and sorted ManagedStream objects

        :param sort_by: field to sort by
        :param reverse: reverse sorting
        :param comparison: comparison operator used for filtering
        :param search_by: fields and values to filter by
        """
        if sort_by and sort_by not in FILTER_FIELDS:
            raise ValueError(f"'{sort_by}' is not a valid field to sort by")
        if comparison and comparison not in COMPARISON_OPERATORS:
            raise ValueError(f"'{comparison}' is not a valid comparison")
        if 'full_status' in search_by:
            del search_by['full_status']
        for search in search_by:
            if search not in FILTER_FIELDS:
                raise ValueError(f"'{search}' is not a valid search operation")
        if search_by:
            comparison = comparison or 'eq'
            streams = []
            for stream in self.streams.values():
                for search, val in search_by.items():
                    if COMPARISON_OPERATORS[comparison](getattr(stream, search), val):
                        streams.append(stream)
                        break
        else:
            streams = list(self.streams.values())
        if sort_by:
            streams.sort(key=lambda s: getattr(s, sort_by))
            if reverse:
                streams.reverse()
        return streams

    async def _check_update_or_replace(self, outpoint: str, claim_id: str, claim: Claim
                                       ) -> typing.Tuple[Optional[ManagedStream], Optional[ManagedStream]]:
        existing = self.get_filtered_streams(outpoint=outpoint)
        if existing:
            return existing[0], None
        existing = self.get_filtered_streams(sd_hash=claim.stream.source.sd_hash)
        if existing and existing[0].claim_id != claim_id:
            raise ResolveError(f"stream for {existing[0].claim_id} collides with existing download {claim_id}")
        if existing:
            log.info("claim contains a metadata only update to a stream we have")
            await self.storage.save_content_claim(
                existing[0].stream_hash, outpoint
            )
            await self._update_content_claim(existing[0])
            return existing[0], None
        else:
            existing_for_claim_id = self.get_filtered_streams(claim_id=claim_id)
            if existing_for_claim_id:
                log.info("claim contains an update to a stream we have, downloading it")
                return None, existing_for_claim_id[0]
        return None, None

    @staticmethod
    def _convert_to_old_resolve_output(wallet_manager, resolves):
        result = {}
        for url, txo in resolves.items():
            if isinstance(txo, Output):
                tx_height = txo.tx_ref.height
                best_height = wallet_manager.ledger.headers.height
                result[url] = {
                    'name': txo.claim_name,
                    'value': txo.claim,
                    'protobuf': binascii.hexlify(txo.claim.to_bytes()),
                    'claim_id': txo.claim_id,
                    'txid': txo.tx_ref.id,
                    'nout': txo.position,
                    'amount': dewies_to_lbc(txo.amount),
                    'effective_amount': txo.meta.get('effective_amount', 0),
                    'height': tx_height,
                    'confirmations': (best_height+1) - tx_height if tx_height > 0 else tx_height,
                    'claim_sequence': -1,
                    'address': txo.get_address(wallet_manager.ledger),
                    'valid_at_height': txo.meta.get('activation_height', None),
                    'timestamp': wallet_manager.ledger.headers[tx_height]['timestamp'],
                    'supports': []
                }
            else:
                result[url] = txo
        return result

    @cache_concurrent
    async def download_stream_from_uri(self, uri, exchange_rate_manager: 'ExchangeRateManager',
                                       timeout: Optional[float] = None,
                                       file_name: Optional[str] = None,
                                       download_directory: Optional[str] = None,
                                       save_file: Optional[bool] = None,
                                       resolve_timeout: float = 3.0,
                                       wallet: Optional['Wallet'] = None) -> ManagedStream:
        manager = self.wallet_manager
        wallet = wallet or manager.default_wallet
        timeout = timeout or self.config.download_timeout
        start_time = self.loop.time()
        resolved_time = None
        stream = None
        txo: Optional[Output] = None
        error = None
        outpoint = None
        if save_file is None:
            save_file = self.config.save_files
        if file_name and not save_file:
            save_file = True
        if save_file:
            download_directory = download_directory or self.config.download_dir
        else:
            download_directory = None

        payment = None
        try:
            # resolve the claim
            if not URL.parse(uri).has_stream:
                raise ResolveError("cannot download a channel claim, specify a /path")
            try:
                response = await asyncio.wait_for(
                    manager.ledger.resolve(wallet.accounts, [uri]),
                    resolve_timeout
                )
                resolved_result = self._convert_to_old_resolve_output(manager, response)
            except asyncio.TimeoutError:
                raise ResolveTimeoutError(uri)
            except Exception as err:
                if isinstance(err, asyncio.CancelledError):  # TODO: remove when updated to 3.8
                    raise
                log.exception("Unexpected error resolving stream:")
                raise ResolveError(f"Unexpected error resolving stream: {str(err)}")
            await self.storage.save_claims_for_resolve([
                value for value in resolved_result.values() if 'error' not in value
            ])
            resolved = resolved_result.get(uri, {})
            resolved = resolved if 'value' in resolved else resolved.get('claim')
            if not resolved:
                raise ResolveError(f"Failed to resolve stream at '{uri}'")
            if 'error' in resolved:
                raise ResolveError(f"error resolving stream: {resolved['error']}")
            txo = response[uri]

            claim = Claim.from_bytes(binascii.unhexlify(resolved['protobuf']))
            outpoint = f"{resolved['txid']}:{resolved['nout']}"
            resolved_time = self.loop.time() - start_time

            # resume or update an existing stream, if the stream changed: download it and delete the old one after
            updated_stream, to_replace = await self._check_update_or_replace(outpoint, resolved['claim_id'], claim)
            if updated_stream:
                log.info("already have stream for %s", uri)
                if save_file and updated_stream.output_file_exists:
                    save_file = False
                await updated_stream.start(node=self.node, timeout=timeout, save_now=save_file)
                if not updated_stream.output_file_exists and (save_file or file_name or download_directory):
                    await updated_stream.save_file(
                        file_name=file_name, download_directory=download_directory, node=self.node
                    )
                return updated_stream

            if not to_replace and txo.has_price and not txo.purchase_receipt:
                payment = await manager.create_purchase_transaction(
                    wallet.accounts, txo, exchange_rate_manager
                )

            stream = ManagedStream(
                self.loop, self.config, self.blob_manager, claim.stream.source.sd_hash, download_directory,
                file_name, ManagedStream.STATUS_RUNNING, content_fee=payment,
                analytics_manager=self.analytics_manager
            )
            log.info("starting download for %s", uri)

            before_download = self.loop.time()
            await stream.start(self.node, timeout)
            stream.set_claim(resolved, claim)
            if to_replace:  # delete old stream now that the replacement has started downloading
                await self.delete_stream(to_replace)

            if payment is not None:
                await manager.broadcast_or_release(payment)
                payment = None  # to avoid releasing in `finally` later
                log.info("paid fee of %s for %s", dewies_to_lbc(stream.content_fee.outputs[0].amount), uri)
                await self.storage.save_content_fee(stream.stream_hash, stream.content_fee)

            self.streams[stream.sd_hash] = stream
            self.storage.content_claim_callbacks[stream.stream_hash] = lambda: self._update_content_claim(stream)
            await self.storage.save_content_claim(stream.stream_hash, outpoint)
            if save_file:
                await asyncio.wait_for(stream.save_file(node=self.node), timeout - (self.loop.time() - before_download),
                                       loop=self.loop)
            return stream
        except asyncio.TimeoutError:
            error = DownloadDataTimeoutError(stream.sd_hash)
            raise error
        except Exception as err:  # forgive data timeout, don't delete stream
            expected = (DownloadSDTimeoutError, DownloadDataTimeoutError, InsufficientFundsError,
                        KeyFeeAboveMaxAllowedError)
            if isinstance(err, expected):
                log.warning("Failed to download %s: %s", uri, str(err))
            elif isinstance(err, asyncio.CancelledError):
                pass
            else:
                log.exception("Unexpected error downloading stream:")
            error = err
            raise
        finally:
            if payment is not None:
                # payment is set to None after broadcasting, if we're here an exception probably happened
                await manager.ledger.release_tx(payment)
            if self.analytics_manager and (error or (stream and (stream.downloader.time_to_descriptor or
                                                                 stream.downloader.time_to_first_bytes))):
                server = self.wallet_manager.ledger.network.client.server
                self.loop.create_task(
                    self.analytics_manager.send_time_to_first_bytes(
                        resolved_time, self.loop.time() - start_time, None if not stream else stream.download_id,
                        uri, outpoint,
                        None if not stream else len(stream.downloader.blob_downloader.active_connections),
                        None if not stream else len(stream.downloader.blob_downloader.scores),
                        None if not stream else len(stream.downloader.blob_downloader.connection_failures),
                        False if not stream else stream.downloader.added_fixed_peers,
                        self.config.fixed_peer_delay if not stream else stream.downloader.fixed_peers_delay,
                        None if not stream else stream.sd_hash,
                        None if not stream else stream.downloader.time_to_descriptor,
                        None if not (stream and stream.descriptor) else stream.descriptor.blobs[0].blob_hash,
                        None if not (stream and stream.descriptor) else stream.descriptor.blobs[0].length,
                        None if not stream else stream.downloader.time_to_first_bytes,
                        None if not error else error.__class__.__name__,
                        None if not error else str(error),
                        None if not server else f"{server[0]}:{server[1]}"
                    )
                )

    async def stream_partial_content(self, request: Request, sd_hash: str):
        return await self.streams[sd_hash].stream_file(request, self.node)