Add new 'type' and 'encryption' labels to weave_connections metric

[hairyhenderson]

Fixes #3788

Notes:

• I don't have a good way of testing this out locally, but make succeeds, so that's encouraging...
• instead of limiting the state label's value to the values in allConnectionStates, the state will reflect whatever's in conn.State (which may be out of sync with allConnectionStates some day? 🤷‍♂)
• I felt like maybe logging some sort of error message if the value of the name attribute was a non-string, but not sure if this is really necessary. Maybe removing the check and allowing a panic instead would be better somehow?

Signed-off-by: Dave Henderson dhenderson@gmail.com

[bboreham]

Hi, if you're not finding time to come back to this I'll pick it up.

[hairyhenderson]

@bboreham thanks - I had this on my ever-growing TODO list, but simply haven't gotten back to it yet... if you're able to handle this that would be much appreciated! 😅

[bboreham]

I added the test, and also the branch needed rebasing so I did that, and then added an encryption label.
See the result at master...add-connection-type-label-to-weave-connection-metric-3788

@hairyhenderson I can try to push that to your branch if you like, or I can merge from my branch.
Either way please take a look and see if you spot any flaws.

[hairyhenderson]

@bboreham thanks! (and sorry again for the slow response time)

Your changes LGTM, and please feel free to push to this branch - I've enabled the Allow edits by maintainers so you should be able to add a commit without issue.

[bboreham]

Smoke-tests won't run when the branch is pushed from a 3rd-party repo, but they did complete at the same commit here:
https://circleci.com/gh/weaveworks/weave/tree/add-connection-type-label-to-weave-connection-metric-3788

[hairyhenderson]

Thanks so much @bboreham - and sorry again for dropping the ball on this one 😅