stable/freqtrade/rpc/api_server/api_ws.py

import logging
import time
from typing import Any, Dict

from fastapi import APIRouter, Depends
from fastapi.websockets import WebSocket
from pydantic import ValidationError

from freqtrade.enums import RPCMessageType, RPCRequestType
from freqtrade.rpc.api_server.api_auth import validate_ws_token
from freqtrade.rpc.api_server.deps import get_message_stream, get_rpc
from freqtrade.rpc.api_server.ws.channel import WebSocketChannel, create_channel
from freqtrade.rpc.api_server.ws.message_stream import MessageStream
from freqtrade.rpc.api_server.ws_schemas import (WSAnalyzedDFMessage, WSMessageSchema,
                                                 WSRequestSchema, WSWhitelistMessage)
from freqtrade.rpc.rpc import RPC


logger = logging.getLogger(__name__)

# Private router, protected by API Key authentication
router = APIRouter()


async def channel_reader(channel: WebSocketChannel, rpc: RPC):
    """
    Iterate over the messages from the channel and process the request
    """
    async for message in channel:
        await _process_consumer_request(message, channel, rpc)


async def channel_broadcaster(channel: WebSocketChannel, message_stream: MessageStream):
    """
    Iterate over messages in the message stream and send them
    """
    async for message, ts in message_stream:
        if channel.subscribed_to(message.get('type')):
            # Log a warning if this channel is behind
            # on the message stream by a lot
            if (time.time() - ts) > 60:
                logger.warning("Channel {channel} is behind MessageStream by 1 minute,"
                               " this can cause a memory leak if you see this message"
                               " often, consider reducing pair list size or amount of"
                               " consumers.")

            await channel.send(message, timeout=True)


async def _process_consumer_request(
    request: Dict[str, Any],
    channel: WebSocketChannel,
    rpc: RPC
):
    """
    Validate and handle a request from a websocket consumer
    """
    # Validate the request, makes sure it matches the schema
    try:
        websocket_request = WSRequestSchema.parse_obj(request)
    except ValidationError as e:
        logger.error(f"Invalid request from {channel}: {e}")
        return

    type, data = websocket_request.type, websocket_request.data
    response: WSMessageSchema

    logger.debug(f"Request of type {type} from {channel}")

    # If we have a request of type SUBSCRIBE, set the topics in this channel
    if type == RPCRequestType.SUBSCRIBE:
        # If the request is empty, do nothing
        if not data:
            return

        # If all topics passed are a valid RPCMessageType, set subscriptions on channel
        if all([any(x.value == topic for x in RPCMessageType) for topic in data]):
            channel.set_subscriptions(data)

        # We don't send a response for subscriptions
        return

    elif type == RPCRequestType.WHITELIST:
        # Get whitelist
        whitelist = rpc._ws_request_whitelist()

        # Format response
        response = WSWhitelistMessage(data=whitelist)
        await channel.send(response.dict(exclude_none=True))

    elif type == RPCRequestType.ANALYZED_DF:
        # Limit the amount of candles per dataframe to 'limit' or 1500
        limit = min(data.get('limit', 1500), 1500) if data else None

        # For every pair in the generator, send a separate message
        for message in rpc._ws_request_analyzed_df(limit):
            # Format response
            response = WSAnalyzedDFMessage(data=message)
            await channel.send(response.dict(exclude_none=True))


@router.websocket("/message/ws")
async def message_endpoint(
    websocket: WebSocket,
    token: str = Depends(validate_ws_token),
    rpc: RPC = Depends(get_rpc),
    message_stream: MessageStream = Depends(get_message_stream)
):
    if token:
        async with create_channel(websocket) as channel:
            await channel.run_channel_tasks(
                channel_reader(channel, rpc),
                channel_broadcaster(channel, message_stream)
            )