No Running Event Loop when table.update is called #2801

yuj2i0 · 2024-10-22T13:42:40Z

yuj2i0
Oct 22, 2024

Hi all,

I have recently upgraded my project from perspective 3.0.3 -> 3.1.1

Encountering this:
Exception has occurred: PyPerspectiveError
External error: PyErr { type: <class 'RuntimeError'>, value: RuntimeError('no running event loop'), traceback: Some(<traceback object at 0x0000025E7BD886C0>) }

main.py

import asyncio
from contextlib import asynccontextmanager
import logging
import threading
from time import sleep
from typing import Optional

from fastapi import FastAPI, WebSocket
from fastapi.middleware.cors import CORSMiddleware
from fastapi.staticfiles import StaticFiles
import pandas as pd
from perspective import Server
from perspective.handlers.starlette import PerspectiveStarletteHandler
import uvicorn


@asynccontextmanager
async def lifespan(app: FastAPI):  # noqa: RUF029
    yield

app = FastAPI(
    title="Hi",
    description="Hi",
    lifespan=lifespan,
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

def make_perspective_app(perspective_server,perspective_loop, app: FastAPI):
    def perspective_thread():
        perspective_loop.run_forever()

    thread = threading.Thread(target=perspective_thread, daemon=True)
    thread.start()

    async def websocket_handler(websocket: WebSocket):
        handler = PerspectiveStarletteHandler(
            perspective_server=perspective_server, websocket=websocket
        )
        await handler.run()

    app.add_api_websocket_route("/data", websocket_handler)

    app.mount("/", StaticFiles(directory=".", html=True), name="static")

    return app

def start_server(app: FastAPI, port: Optional[int] = None, threaded: bool = True):
    port_to_use = port
    logging.critical(f"Listening on http://localhost:{port_to_use}")
    if threaded:
        thread = threading.Thread(
            target=uvicorn.run,
            args=(app,),
            kwargs={"host": "0.0.0.0", "port": port_to_use},
            daemon=True,
        )
        thread.start()
        if port is None:
            return port_to_use
        return thread
    uvicorn.run(app, host="0.0.0.0", port=port_to_use)

def main():
    perspective_server = Server()
    perspective_loop = asyncio.new_event_loop()
    perspective_client = perspective_server.new_local_client(
        loop_callback=perspective_loop.call_soon_threadsafe
    )
    Table = perspective_client.table
    test1 = Table({"id": "string", "value":"float"}, index="id", name="temp_table")
    make_perspective_app(perspective_server,perspective_loop, app)
    ## Declare Perspective Table 
    
    thread = start_server(app, 8080)
    ## During Sleep Open localhost:8080/index.html
    sleep(10) 
    ## Open localhost/index.html
    df = pd.DataFrame(
        {
            "id": ["Id 1"],
            "value": [float(500)],
        }
    )
    perspective_client.open_table("temp_table").update(df)
    print("Updated")
    thread.join()

if __name__ == "__main__":
    main()

index.html

<html>

<head>
  <script type="module" src="https://cdn.jsdelivr.net/npm/@finos/perspective/dist/cdn/perspective.js"></script>
  <script type="module"
    src="https://cdn.jsdelivr.net/npm/@finos/perspective-viewer/dist/cdn/perspective-viewer.js"></script>
  <script type="module"
    src="https://cdn.jsdelivr.net/npm/@finos/perspective-viewer-datagrid/dist/cdn/perspective-viewer-datagrid.js"></script>
  <script type="module"
    src="https://cdn.jsdelivr.net/npm/@finos/perspective-viewer-d3fc/dist/cdn/perspective-viewer-d3fc.js"></script>
  <link rel="stylesheet" crossorigin="anonymous"
    href="https://cdn.jsdelivr.net/npm/@finos/perspective-viewer/dist/css/themes.css" />

  <style>
    perspective-viewer {
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
    }
  </style>
</head>

<body>
  <perspective-viewer id="viewer" ,> </perspective-viewer>

  <script type="module">
    import perspective from "https://cdn.jsdelivr.net/npm/@finos/perspective/dist/cdn/perspective.js";
    window.addEventListener("DOMContentLoaded", async function () {
      // Create a client that expects a Perspective server
      // to accept connections at the specified URL.
      const websocket = await perspective.websocket(
        "ws://localhost:8080/data"
      );

      // Get a handle to the Table on the server
      const server_table = await websocket.open_table("temp_table");

      // Create a new view
      const server_view = await server_table.view();

      // Create a Table on the client using `perspective.worker()`
      const worker = await perspective.worker();
      const client_table = await worker.table(server_view, { index: "id" });

      // Load the client table in the `<perspective-viewer>`.
      document.getElementById("viewer").load(client_table);


      viewer.restore
        (
          {
            "version": "2.10.1",
            "plugin": "Datagrid",
            "plugin_config": {
              "columns": {},
              "editable": false,
              "scroll_lock": false
            },
            "columns_config": {},
            "settings": true,
            "theme": "Pro Dark",
            "title": null,
            "group_by": [
              "Year",
              "Month",
              "Day"
            ],
            "split_by": [],
            "columns": [
              "impact_of_px_approx_index_ccy",
              "total_approximated_pnl",
              "total_value"
            ],
            "filter": [],
            "sort": [],
            "expressions": {},
            "aggregates": {}
          }
        )
      viewer.toggleConfig();
    });
  </script>
</body>

</html>

Anyone encountered this before?

tomjakubowski · 2024-10-22T23:04:59Z

tomjakubowski
Oct 22, 2024

It's not clear what's happening in your example, because it's missing definitions of make_prospective_app, start_server, perspective_client, etc.

If you would post a complete example which reproduces the error, I'll see if I can help. A git repo including a pyproject.toml or requirements.txt with the exact dependency versions you're using would be ideal.

1 reply

yuj2i0 Oct 22, 2024
Author

Hi there,

Thank you for taking the time out to help with this!
I have updated my initial post with the .py file and index.html, hopefully that should be enough.
IMPORTANT: Load up localhost:8080/index.html before the update occurs, sleep is there to give you enough time to load the page
If not github_repo here
https://github.com/yuj2i0/perspective-example

I validated my example works smoothly on 3.0.3 but version 3.1.1 >= encounters the error in the original post

yuj2i0 · 2024-11-11T15:25:12Z

yuj2i0
Nov 11, 2024
Author

Fixed by 3.14 Release

0 replies

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No Running Event Loop when table.update is called #2801

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