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/*
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Conat WebSocket proxy -- this primarily just directly proxied the conats
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socketio websocket server, so outside browsers can connect to it.
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So far I'm only using this for testing, but it could be useful in a non-kubernetes
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setting, where we need certain types of scalability.
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*/
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import { createProxyServer, type ProxyServer } from "http-proxy-3";
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import getLogger from "@cocalc/backend/logger";
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import {
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  conatServer as conatServer0,
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  conatClusterPort,
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} from "@cocalc/backend/data";
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import basePath from "@cocalc/backend/base-path";
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import { conat } from "@cocalc/backend/conat";
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import { type Client } from "@cocalc/conat/core/client";
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import { delay } from "awaiting";
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const logger = getLogger("hub:proxy-conat");
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const ADDRESS_UPDATE_INTERVAL = 30_000;
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export async function proxyConatWebsocket(req, socket, head) {
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  const i = req.url.lastIndexOf("/conat");
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  const target = randomServer() + req.url.slice(i);
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  logger.debug(`conat proxy -- proxying a WEBSOCKET connection to ${target}`);
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  // todo -- allowing no cookie, since that's used by projects and compute servers!
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  // do NOT disable this until compute servers all set a cookie... which could be a long time.
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  // make the proxy server
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  const proxy: ProxyServer = createProxyServer({
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    ws: true,
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    secure: false,
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    target,
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  });
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  proxy.on("error", (err) => {
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    logger.debug(`WARNING: conat websocket proxy error -- ${err}`);
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  });
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  // connect the client's socket to conat via the proxy server:
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  proxy.ws(req, socket, head);
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}
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let client: Client | null = null;
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let addresses: string[] = [];
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function randomServer(): string {
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  if (client == null) {
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    addressUpdateLoop();
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  }
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  if (addresses.length == 0) {
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    addresses.push(
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      conatServer0
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        ? conatServer0
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        : `http://localhost:${conatClusterPort}${basePath.length > 1 ? basePath : ""}`,
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    );
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    return addresses[0];
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  }
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  // random choice
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  const i = Math.floor(Math.random() * addresses.length);
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  return addresses[i];
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}
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async function addressUpdateLoop() {
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  client = conat();
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  await client.waitUntilSignedIn();
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  if (!client.info?.clusterName) {
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    // no point -- not a cluster
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    return;
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  }
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  while (true) {
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    try {
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      addresses = await client.cluster();
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      logger.debug("addressUpdateLoop: got", addresses);
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    } catch (err) {
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      logger.debug(
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        "addressUpdateLoop: error -- updating cluster addresses",
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        err,
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      );
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    }
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    await delay(ADDRESS_UPDATE_INTERVAL);
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  }
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}
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