Resizing terminal from the dashboard fails

[David Edler]

When opening the instance terminal in Anbox cloud dashboard, the remote terminal process gets informed of the available lines and columns when opening the connection. On resize of the browser, a request to update the size is sent through the control websocket with updated dimensions. However, this does not always update the $LINES or $COLUMNS variables in the running terminal session.

While resizing the terminal sometimes works, in other occasions, it fails.

When restarting LXD, it surfaces several log message about several dozen, still open websocket connections being closed on the restart. It could be, that AMS is not closing the control connection properly and exceeding a limit of open connections in LXD over time.

[Michele Lo Russo (lorumic)]

Adding steps to reproduce the issue:

1. Go to https://<your-dashboard-ip>/instances/<cluster-id>/<instance-id>/terminal
2. Write "tput cols", take note of the output, e.g. 120
3. Resize your browser window, e.g. make it smaller
2. Write again "tput cols", see that you get exactly the same output as in step 2, instead that a smaller value
5. Wait a bit, the "connection closed abnormally" error will display in the form of a failure notification

[Simon Fels (morphis)]

I cannot reproduce the "tput cols" problem on a fresh installation so far. The value is always correctly reported so there seems to be more needed to trigger this.

[Simon Fels (morphis)]

Fixes for this have been merged.