Better error handling on Zulip

[alexmv]

We noticed that matterbridge bots were making thousands of requests to Zulip servers with unauthenticated credentials. This is an attempt to stem that tide.

Specifically, it catches failures when registering, which were previously completely ignored -- most of the unauthenticated requests were to yourserver.zulipchat.com which is the example host in the configuration, which isn't currently a valid Zulip realm:

matterbridge/matterbridge.toml.sample

Lines 1564 to 1582 in 53cafa9

	[zulip]
	#You can configure multiple servers "[zulip.name]" or "[zulip.name2]"
	#In this example we use [zulip.streamchat]
	#REQUIRED
	[zulip.streamchat]
	#Token to connect with zulip API (called bot API key in Settings - Your bots)
	#REQUIRED
	Token="Yourtokenhere"
	#Username of the bot, normally called yourbot-bot@yourserver.zulipchat.com
	#See username in Settings - Your bots
	#REQUIRED
	Login="yourbot-bot@yourserver.zulipchat.com"
	#Servername of your zulip instance
	#REQUIRED
	Server="https://yourserver.zulipchat.com"

It also catches the 401's when fetching events, which were not rate-limited previously.

Finally, it provides a more specific user-agent, which will make it easier to track down errors like this in the future. It does so by doing a small re-arrangement of packages to make the version information available via a package which is not main.

I made commits directly into vendor/github.com/matterbridge/gozulipbot/ directly, rather than open a PR against https://github.com/matterbridge/gozulipbot. It looks like the gozulipbot code in this repo has already diverged from the other repository, so it looked easier to fix it here. Regardless, however, the key flaws of failing to check for failure during queue registration and failing to rate-limit 401 responses also apply to the matterbridge/gozulipbot repository, and should also be applied there.

I'm happy to open a second PR there if you'd prefer; let me know how you'd like to proceed, as it looks like there are changes other than these which need backporting out of vendor/ and into matterbridge/gozulipbot.

[alexmv]

Gentle poke on this?

[42wim]

@alexmv Thank you very much! and sorry for the delay.

The gozulipbot vendor is uptodate, but it's against the work branch.

Could you make your PR against https://github.com/matterbridge/gozulipbot/tree/work ?
I'll update the matterbridge dependencies afterwards.

This PR can be closed then, let me know if that's okay for you.

[alexmv]

I've pushed the gozulipbot-specific changes to matterbridge/gozulipbot#1; this PR shouldn't be closed, because there are changes that are not contained within the vendored gozulipbot.

I've rebased, dropping the gozulipbot-only changes, and re-pushed. This is not expected to pass tests until it is rebased past a commit which pulls in the gozulipbot changes.

[codeclimate]

Code Climate has analyzed commit 8e4906a and detected 1 issue on this pull request.

Here's the issue category breakdown:

Category	Count
Complexity	1

View more on Code Climate.

[42wim]

Thanks!