🚀 Always launch a new Jupyter Server

Fixes #1716

.changeset/strange-baboons-build.md

@@ -0,0 +1,5 @@
+---
+"myst-cli": patch
+---
+
+Do not findExistingJupyterServer when using execute

docs/execute-notebooks.md

@@ -32,12 +32,13 @@ In order to execute your MyST content, you must install a Jupyter Server and the
 ## Expect a code-cell to fail
 
 By default, MyST will stop executing a notebook if a cell raises an error.
-If instead you'd like MyST to continue executing subsequent cells (e.g., in order to demonstrate an expected error message), add the `raises-exception` tag to the cell.
+If instead you'd like MyST to continue executing subsequent cells (e.g., in order to demonstrate an expected error message), add the `raises-exception` tag to the cell (see [all cell tags](#tbl:notebook-cell-tags)).
 If a cell with this tag raises an error, then the error is provided with the cell output, and MyST will continue executing the rest of the cells in a notebook.
 
+## Adding Tags to Notebook Cells
+
 The easiest way to add cell tags is via [the JupyterLab interface](https://jupyterlab.readthedocs.io).
 Additionally, you can specify tags (and other cell metadata) with markdown using the {myst:directive}`code-cell` directive.
-
 Here's an example of adding this tag with a {myst:directive}`code-cell` directive:
 
 ````markdown
@@ -62,6 +63,8 @@ name = input("What is your name?")
 ```
 ````
 
+Additional [cell tags](#tbl:notebook-cell-tags) to hide, remove, or raise exceptions are also possible.
+
 ## Cache execution outputs
 
 When MyST executes your notebook, it will store the outputs in a cache in a folder called `execute/` in your MyST build folder.
@@ -98,7 +101,7 @@ Jupyter Server is only responsible for orchestrating execution of your code. To
 pip install ipykernel
 ```
 
-If Jupyter Server is installed and the `--execute` flag is passed to `myst start` or `myst build`, then MyST will attempt to find a healthy existing Jupyter Server. Internally, this is performed using `python -m jupyter_server list`. If no existing servers are found, then MyST will attempt to launch one using `python -m jupyter_server`.
+If Jupyter Server is installed and the `--execute` flag is passed to `myst start` or `myst build` MyST will attempt to launch a Jupyter Server using `python -m jupyter_server`.
 
 ## Manually launch a Jupyter server
 

packages/myst-cli/src/session/session.ts

@@ -25,7 +25,7 @@ import type { ISession } from './types.js';
 import { isWhiteLabelled } from '../utils/whiteLabelling.js';
 import { KernelManager, ServerConnection, SessionManager } from '@jupyterlab/services';
 import type { JupyterServerSettings } from 'myst-execute';
-import { findExistingJupyterServer, launchJupyterServer } from 'myst-execute';
+import { launchJupyterServer } from 'myst-execute';
 import type { RequestInfo, RequestInit } from 'node-fetch';
 import { default as nodeFetch, Headers, Request, Response } from 'node-fetch';
 
@@ -229,16 +229,10 @@ export class Session implements ISession {
           token: process.env.JUPYTER_TOKEN,
         };
       } else {
-        // Load existing running server
-        const existing = await findExistingJupyterServer(this);
-        if (existing) {
-          this.log.debug(`Found existing server on: ${existing.appUrl}`);
-          partialServerSettings = existing;
-        } else {
-          this.log.debug(`Launching jupyter server on ${this.sourcePath()}`);
-          // Create and load new server
-          partialServerSettings = await launchJupyterServer(this.sourcePath(), this.log);
-        }
+        // Note: To use an existing Jupyter server use `findExistingJupyterServer`, see #1716
+        this.log.debug(`Launching jupyter server on ${this.sourcePath()}`);
+        // Create and load new server
+        partialServerSettings = await launchJupyterServer(this.sourcePath(), this.log);
       }
 
       const serverSettings = ServerConnection.makeSettings(partialServerSettings);