An offline workspace with a file sync session is accessed using `coder ssh` if `config-ssh` was run

[ethanndickson]

The latest coder config-ssh creates an SSH config item that fallsback to coder ssh if the Coder Connect hostname is unavailable. This means if a file sync session exists for a workspace that's currently offline, rather than failing to connect, Mutagen uses the SSH config and attempts to connect to that workspace using coder ssh, this in-turn automatically starts the workspace, and then when the Mutagen operation times out, cancels the build.

These are the Mutagen logs relayed via the Coder Desktop logs:

2025-04-23 14:17:14.123009 [E] [sync.sync_43eBU5AW.beta] Workspace was stopped, starting workspace to allow connecting to "pog11"...
2025-04-23 14:17:15.717849 [E] [sync.sync_43eBU5AW.beta] Planning workspace...
2025-04-23 14:17:15.955351 [E] [sync.sync_43eBU5AW.beta] === ✔ Queued [0ms]
2025-04-23 14:17:15.955395 [E] [sync.sync_43eBU5AW.beta] ==> ⧗ Running
2025-04-23 14:17:15.955401 [E] [sync.sync_43eBU5AW.beta] ==> ⧗ Running
2025-04-23 14:17:17.340596 [E] [sync.sync_43eBU5AW.beta] === ✔ Running [14ms]
2025-04-23 14:17:17.340645 [E] [sync.sync_43eBU5AW.beta] ==> ⧗ Setting up
2025-04-23 14:17:17.340654 [E] [sync.sync_43eBU5AW.beta] === ✔ Setting up [71ms]
2025-04-23 14:17:17.340668 [E] [sync.sync_43eBU5AW.beta] ==> ⧗ Detecting persistent resources
2025-04-23 14:17:17.911125 [E] [sync.sync_43eBU5AW.beta] Connection timed out during banner exchange
2025-04-23 14:17:34.113115 [E] [sync.sync_43eBU5AW.beta] Workspace was stopped, starting workspace to allow connecting to "pog11"...
2025-04-23 14:17:35.837161 [E] [sync.sync_43eBU5AW.beta] Planning workspace...

One way to fix this might be to patch our Mutagen build to ignore the SSH config. This should be fine as nobody should ever need or want to customize the SSH config used by the file sync connection.

This was observed on Mac, but presumably occurs on Windows too.

[ibetitsmike]

1. Consider the option of using env variables when making the connection to mark the session as mutagen.
2. Go with the solution to create an option to specify a new ssh config for mutagen.

[matifali]

Or let us make mutagen in Coder Desktop work exclusively on Coder Connect tunnel and not fallback to CLI i.e. coder ssh.

[ethanndickson]

That's what's accomplished by the second option above, creating an option on Mutagen to specify the SSH config to use.