Does the Remote SSH Console hang when opening any workspace?

[marcdotson]

I'm assuming this latest question continues to be simple ignorance on my part, but I'm wondering why the Remote SSH Console functionality doesn't play well with uv or cloned repositories?

Here's my attempt at making this reproducible:

• Spin up an AWS EC2 (Ubuntu 24.04, t2.micro)
• Connect and install uv with curl -LsSf https://astral.sh/uv/install.sh | sh and restart with exec bash
• Clone this test repo with git clone https://github.com/marcdotson/begin-with-bayes.git

So far so good? Here's where the path diverges:

• Running /clone/test.py from the terminal with uv run clone/test.py works
• Opening the begin-with-bayes folder with the Positron Explorer, opening /clone/test.py and trying to run it by sending it to the Console fails

Specifically, Positron says "Setting up SSH Host" and struggles to have a Console session start before the Remote SSH connection fails and tries to reconnect but can't. As a bonus, I can go to the terminal and connect to this same EC2 instance and still run everything successfully.

It looks like Positron is set up on the server-side with a version of Python using pyenv (but not pip?), so maybe it's uv that isn't playing well with the Console? But then I haven't been able to get any code to run in the Console once I open the cloned repository on the remote, so maybe that's what's failing?

[marcdotson]

Or maybe it's even more fundamental? Opening any folder in Positron on the server-side appears to lead to the Console hanging up and the SSH tunnel disconnecting and not being able to reconnect -- no uv or clone repository needed.

[austin3dickey]

Hey @marcdotson , thanks for the issue. Could you paste the output of the About Positron menu item?

I can't reproduce the problem, but I probably have a fairly different setup from you. Here's what I tried:

• From Positron, connect to an ubuntu host (it already has uv, git, and a uv-managed python 3.10 on its PATH)
• From the Positron terminal, do git clone https://github.com/marcdotson/begin-with-bayes.git
• Click "Open Folder" and select begin-with-bayes
• Trust this folder
  • Only after trusting it does a Console start up with my python 3.10
• Try uv run code/test.py in the Positron terminal
  • This fails because uv can't find an available distribution of python 3.13.4 that's compatible with my ubuntu OS
• Switch the .python-version file to 3.13.3 and try uv run code/test.py again. This works!
• Open code/test.py in the editor and click the play button to run the file.
  • This fails because my python 3.10 console environment doesn't have numpy
• Use the Interpreter: Discover All Interpreters command to pick up the new 3.13 .venv interpreter that uv just created, and select that interpreter for a new Console session
• Run the file with the play button again. It works!

Hopefully something in there helps you? If not, I'd be interested to see some logs. Particularly, in the Output tab, the Remote - SSH logs and Python Language Pack logs. If they're too big to paste here, I think you can upload them as .txt files.

[marcdotson]

Thanks, Austin. Here's the About Positron details:

Positron Version: 2025.06.0 (Universal) build 167
Code - OSS Version: 1.100.0
Commit: e7e5d55
Date: 2025-05-29T20:44:08.369Z
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.5.0

I'll try and produce the logs you requested. To confirm, was your ubuntu host on a t2.micro? Since it worked via the command line but not using Positron, I've been wondering if a t2.micro is just too small to run Positron.

[jthomasmock]

Thanks @marcdotson for the feedback!

The general guideline I follow is RAM 5-10x the data size, so even for just 500 MB of data, I’d need something like 2.5 to 5 GB of RAM on top of the compute needed to run Positron components.

While our implementation is different, per the VS Code remote SSH docs: https://code.visualstudio.com/docs/remote/ssh#_system-requirements

1 GB RAM is required for remote hosts, but at least 2 GB RAM and a 2-core CPU is recommended.

Especially for data-science work that can be RAM intensive, I wouldn’t suggest less than a 4 GB instance, although it’s likely that somewhere between 2-4 GB of RAM is sufficient to operate Positron REH itself. We're in progress on some specific load and performance testing to further dial in our recommendations for sizing of Positron sessions on Workbench, and that will also be informative for Remote SSH sessions.

[marcdotson]

Thanks, @jthomasmock. I was just sticking with a t2.micro to test spinning up a virtual machine on the free tier. I did try it with a t2.medium, which has 4 GB of RAM, and Positron worked fine -- except that the Interpreter: Discover All Interpreters command, like @austin3dickey recommended, still didn't find the version of Python I had installed using uv.

Maybe I should post this as a separate discussion, but since it's related -- is there a plan to have Positron remote spin up automatically using uv anyway? I would assume so given how fast it is (and how deeply integrated it is in {reticulate} now)?

[austin3dickey]

the Interpreter: Discover All Interpreters command still didn't find the version of Python I had installed using uv

Hm, this is strange. Just to confirm, you've opened a workspace that already has a .venv/bin/python interpreter, but it's not showing up in the list? If so, some things to check:

• Does a restart help?
• Can you update to the newest version of Positron? We've made some changes to uv location since the version you're using.
• Can you confirm the value of your python.locator setting?
• Check the log channels I mentioned above

Some more docs around the discovery process: https://positron.posit.co/python-installations.html

is there a plan to have Positron remote spin up automatically using uv anyway?

Yeah, this would be good for a separate discussion. I'm curious what your ideas are on how this would work! We've recently made changes such that if you have uv installed on your system, you can create a new project via the UI using its commands. And we have some future ideas like #6965, #7714, #6966.

[marcdotson]

Thanks, @austin3dickey.

A restart did help! This is still using the latest monthly release, 2025.06.0 (Universal) build 167. Running Interpreter: Discover All Interpreters discovered the uv-installed Python version on the t2.medium this time. The python.locator value was set to js (default). I've attached the requested logs as .txt files.

I'll create a separate discussion on this second topic. Thanks again!

Remote-SSH Log.txt
Python Language Pack Log.txt

[austin3dickey]

From the Python Language Pack logs, it looks like Positron attempted to call the uv binary but couldn't find it, so it disabled uv support for that session. I'm not exactly sure why it couldn't find the uv binary; perhaps it wasn't on the PATH when Positron started, or something else went wrong there. Either way, glad the restart helped!