Support RFC3164 syslog entries

[sushain97]

PR Description

Ports the changes from grafana/loki#12810 here.

Which issue(s) this PR fixes

Fixes #305.

Notes to the Reviewer

Suggest reviewing commit-by-commit.

PR Checklist

• CHANGELOG.md updated
• Documentation added
• Tests updated
• Config converters updated

[CLAassistant]

All committers have signed the CLA.

[sushain97]

@clayton-cornell it looks like there's one test failing (really timing out):

FAIL	github.com/grafana/alloy/internal/component/loki/process	600.159s

I doubt that it's related to this PR per se but it could be from the bump to github.com/grafana/loki/v3 ?

[clayton-cornell]

it could be from the bump to github.com/grafana/loki/v3 ?

Possible. The macos test fails once in a while. I'll leave it as-is for now.

First we need a code review from someone in @grafana/grafana-alloy-maintainers.

[wildum]

LGTM, only two small comments for the Alloy part

[sushain97]

@wildum @ptodev Thanks for taking a look! I think I've addressed the comments.

[sushain97]

@ptodev thanks for triggering tests! I just pushed a fix for the failing one.

[clayton-cornell]

Approving for docs

[sushain97]

@ptodev is this good to merge?

[ptodev]

Hi @wildum, would you mind reviewing the PR again please? It should be ready to merge, but I pushed a few changes to it and it'd be nice to have some else double check them :)

[sboschman]

Would it be easy to add 'raw' as format, apart from 'RFC3164' and 'RFC5424' formats? So, the parsing of the message can be done in a loki.process component.

I have firewall devices sending syslog messages in CEF format.

[sushain97]

@sboschman I'd suggest creating an issue for that, it's probably best as a separate PR.

[sushain97]

@wildum @ptodev please let me know if I should resolve the conflicts with master. Don't want to resolve them just to see it get conflicted again 😅

[sushain97]

@ptodev @wildum 👋 Just checking in again on this. I'm happy to resolve the conflicts if someone can merge it afterwards.

[wildum]

Sorry for the delay, I missed the notifications. LGTM, I will merge once the conflicts are resolved

[sushain97]

@wildum no worries, thanks for taking a look! I've merged master to eliminate the conflicts.

[sushain97]

There's one failing test but it doesn't look related?

--- FAIL: TestAdditionalLabels (3.01s)
    events_test.go:276: 
        	Error Trace:	/drone/src/internal/component/mimir/rules/kubernetes/events_test.go:276
        	            				/usr/local/go/src/runtime/asm_amd64.s:1695
        	Error:      	Not equal: 
        	            	expected: 1
        	            	actual  : 0
        	Test:       	TestAdditionalLabels
    events_test.go:272: 
        	Error Trace:	/drone/src/internal/component/mimir/rules/kubernetes/events_test.go:272
        	Error:      	Condition never satisfied
        	Test:       	TestAdditionalLabels
level=info ts=2024-09-27T07:54:17.90219047Z msg="shutting down event loop"
FAIL
FAIL	github.com/grafana/alloy/internal/component/mimir/rules/kubernetes	3.360s

[wildum]

yeah seems like a flaky test, restarting the build