Adding LXD with nonexistent address returns empty error

[Huw Wilkins]

On Bolla I tried to add a LXD with the address `1.2.3.4` which eventually returned an empty message over the websocket. This could possibly have been a timeout that wasn't handled.

Message:
```
method: "pod.get_projects"
params: {password: "", power_address: "1.2.3.4", type: "lxd"}
password: ""
power_address: "1.2.3.4"
type: "lxd"
request_id: 11
type: 0
```
Response:
```
error: ""
request_id: 11
rtype: 1
type: 1
```

[Huw Wilkins (huwshimi)]

I also passed a `power_address` of `somenonipstring` and I got an unhandled error (see attached).

[Alberto Donato (ack)]

There are two different cases here:

- passing a valid address (like 1.2.3.4) which isn't reachable will have a very long timeout (MAAS sends the request but nothing comes back)

- passing an unknown hostname (like "somenonipstring") is (correctly) failing, but hitting https://bugs.launchpad.net/maas/+bug/1922569, which is preventing the error message from being displayed correctly.

[Huw Wilkins (huwshimi)]

These errors should contain links: https://bugs.launchpad.net/maas/+bug/1928621.

[Huw Wilkins (huwshimi)]

I hit this again today, when providing an LXD address that wasn't correct it had the same empty response.

Sending:

```
{
    "method": "pod.get_projects",
    "type": 0,
    "params": {
        "password": "",
        "power_address": "1.2.3.4:1234",
        "type": "lxd"
    },
    "request_id": 8
}
```

A few minutes later returned:

```
{
    "type": 1,
    "request_id": 8,
    "rtype": 1,
    "error": ""
}
`

[Adam Collard (adam-collard)]

Is this still an issue in a recent version of MAAS (3.3 onwards)? The websocket code for handling LXD projects and instances has changed since this bug was filed

[Launchpad Janitor (janitor)]

[Expired for MAAS because there has been no activity for 60 days.]