chore: retire legacy v3 dev websocket execution + legacy self-hosting docs

The v3 (engine V1) is end-of-lifed and enforced off in prod. Remove the dead
legacy execution behind the deprecated dev websocket while KEEPING the
user-facing deprecation message so old `trigger dev` CLIs are still told to
upgrade:

- app/v3/handleWebsockets.server.ts: the /ws websocket is only used by the
  legacy v3 dev CLI (v4 uses a different transport). Authenticate, then close
  with V3_DEV_DEPRECATION_MESSAGE. Drops the AuthenticatedSocketConnection /
  DevQueueConsumer legacy path that can no longer run.
- Delete app/v3/authenticatedSocketConnection.server.ts (its only consumer).

Docs: delete the intentionally-legacy 'Docker (legacy)' self-hosting page and
redirect /open-source-self-hosting (+ the /v3 alias) to /self-hosting/overview;
repoint the two inbound links.

Scoped deliberately: MarQS and the rest of the v3-engine removal are left for a
follow-up - MarQS is entangled with live v2 queue/metrics/cleanup code and
needs a per-file reviewed pass, not a bulk delete.

Author: nicktrn

apps/webapp/app/v3/authenticatedSocketConnection.server.ts

@@ -3,31 +3,15 @@ import { WebSocketServer, type WebSocket } from "ws";
 import { authenticateApiKey } from "~/services/apiAuth.server";
 import { logger } from "~/services/logger.server";
 import { singleton } from "../utils/singleton";
-import { AuthenticatedSocketConnection } from "./authenticatedSocketConnection.server";
-import { Gauge } from "prom-client";
-import { metricsRegister } from "~/metrics.server";
-import { isV3Disabled, V3_DEV_DEPRECATION_MESSAGE } from "./engineDeprecation.server";
+import { V3_DEV_DEPRECATION_MESSAGE } from "./engineDeprecation.server";
 
 export const wss = singleton("wss", initalizeWebSocketServer);
 
-let authenticatedConnections: Map<string, AuthenticatedSocketConnection>;
-
 function initalizeWebSocketServer() {
   const server = new WebSocketServer({ noServer: true });
 
   server.on("connection", handleWebSocketConnection);
 
-  authenticatedConnections = new Map();
-
-  new Gauge({
-    name: "dev_authenticated_connections",
-    help: "Number of authenticated dev connections",
-    collect() {
-      this.set(authenticatedConnections.size);
-    },
-    registers: [metricsRegister],
-  });
-
   return server;
 }
 
@@ -59,35 +43,14 @@ async function handleWebSocketConnection(ws: WebSocket, req: IncomingMessage) {
 
   const authenticatedEnv = authenticationResult.environment;
 
-  // This legacy websocket is only used by the v3 `trigger dev` CLI (v4 uses a
-  // different dev transport). When the v3 shutdown is on, close it with a
-  // graceful reason instead of letting the CLI sit connected with no work.
-  if (isV3Disabled()) {
-    logger.warn("Rejected deprecated v3 dev CLI websocket connection", {
-      environmentId: authenticatedEnv.id,
-      projectId: authenticatedEnv.projectId,
-      organizationId: authenticatedEnv.organizationId,
-    });
-    ws.close(1008, V3_DEV_DEPRECATION_MESSAGE);
-    return;
-  }
-
-  const authenticatedConnection = new AuthenticatedSocketConnection(
-    ws,
-    authenticatedEnv,
-    req.headers["x-forwarded-for"] ?? req.socket.remoteAddress ?? "unknown"
-  );
-
-  authenticatedConnections.set(authenticatedConnection.id, authenticatedConnection);
-
-  authenticatedConnection.onClose.attachOnce((closeEvent) => {
-    logger.debug("Websocket closed", {
-      closeEvent,
-      authenticatedConnectionId: authenticatedConnection.id,
-    });
-
-    authenticatedConnections.delete(authenticatedConnection.id);
+  // This websocket is only used by the legacy v3 `trigger dev` CLI (v4 uses a
+  // different dev transport). The v3 engine is end-of-lifed, so there is no
+  // longer any work to run here — close with the graceful upgrade message so
+  // an old CLI is told what to do instead of sitting connected.
+  logger.warn("Rejected deprecated v3 dev CLI websocket connection", {
+    environmentId: authenticatedEnv.id,
+    projectId: authenticatedEnv.projectId,
+    organizationId: authenticatedEnv.organizationId,
   });
-
-  await authenticatedConnection.initialize();
+  ws.close(1008, V3_DEV_DEPRECATION_MESSAGE);
 }

apps/webapp/app/v3/handleWebsockets.server.ts

@@ -286,8 +286,7 @@
               {
                 "group": "Environment variables",
                 "pages": ["self-hosting/env/webapp", "self-hosting/env/supervisor"]
-              },
-              "open-source-self-hosting"
+              }
             ]
           },
           {
@@ -735,9 +734,13 @@
       "source": "/v3/upgrading-from-v2",
       "destination": "/guides/use-cases/upgrading-from-v2"
     },
+    {
+      "source": "/open-source-self-hosting",
+      "destination": "/self-hosting/overview"
+    },
     {
       "source": "/v3/open-source-self-hosting",
-      "destination": "/open-source-self-hosting"
+      "destination": "/self-hosting/overview"
     },
     {
       "source": "/v3/:slug*",

docs/docs.json

@@ -5,4 +5,4 @@ url: "https://github.com/triggerdotdev/trigger.dev"
 
 Trigger.dev is [Open Source on GitHub](https://github.com/triggerdotdev/trigger.dev). You can contribute to the project by submitting issues, pull requests, or simply by using it and providing feedback.
 
-You can also [self-host](/open-source-self-hosting) the project if you want to run it on your own infrastructure.
+You can also [self-host](/self-hosting/overview) the project if you want to run it on your own infrastructure.