Cannot join an active session on some of the clusters (4.3)

[alex-kovoy]

The endpoint which returns an active session information may return an empty cluster_name field (which has been added in 4.3) thus preventing webui from joining a session. This has been observed on cluster upgraded from 4.2 to 4.3 using the dir storage.

/v1/webapi/sites/:siteID/sessions/:SID

{
  id: "XX"
  namespace: "default"
  parties: [{id: "XXX", remote_addr: "XXX",…}]
  terminal_params: {w: 80, h: 25}
  login: "root"
  created: "2020-07-10T16:08:25.033352638Z"
  last_active: "2020-07-10T16:08:25.033354254Z"
  server_id: "61ada453-eb22-4692-b07f-9c729ad35b83"
  server_hostname: ""
  server_addr: ""
  cluster_name: ""
}

There are 2 things that we can do:

1. Understand why cluster_name might be empty.
2. If we cannot guarantee an availability of this field after upgrading from 4.2 to 4.3 then make UI more resilient - if empty, take this value from URL.

[stevenGravy]

This is specifically happening with a 4.2.X agent with a 4.3.0 proxy/auth. A 4.3.0 agent works. Note that the webui is that part that doesn't work. tsh joining does work.

[russjones]

Best: 1
Realistic: 1