lokiexporter: Implementation ( PR 2/3 )

[gramidt]

Description:
The implementation of the Loki exporter.

Link to tracking Issue:
#1894

Testing:
Unit Tests

Documentation:
Godoc and README

Notes:
#1952 was the original PR, but we were unable to re-open it after it was closed for being stale.

[codecov]

Codecov Report

Merging #2262 (6e323bf) into main (339dd56) will increase coverage by 0.02%.
The diff coverage is 96.19%.

@@            Coverage Diff             @@
##             main    #2262      +/-   ##
==========================================
+ Coverage   90.60%   90.62%   +0.02%     
==========================================
  Files         401      402       +1     
  Lines       19899    19985      +86     
==========================================
+ Hits        18029    18111      +82     
- Misses       1413     1414       +1     
- Partials      457      460       +3     

Flag	Coverage Δ
integration	69.26% <ø> (-0.07%)	⬇️
unit	89.44% <96.19%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
exporter/lokiexporter/exporter.go	94.80% <94.80%> (ø)
exporter/lokiexporter/config.go	100.00% <100.00%> (ø)
exporter/lokiexporter/factory.go	94.73% <100.00%> (-5.27%)	⬇️
receiver/k8sclusterreceiver/watcher.go	95.29% <0.00%> (-2.36%)	⬇️
processor/groupbytraceprocessor/event.go	95.96% <0.00%> (-0.81%)	⬇️
receiver/prometheusexecreceiver/receiver.go	88.33% <0.00%> (+2.50%)	⬆️

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[gramidt]

Happy Tuesday, @kbrockhoff!

Hope your week is off to a great start! Do you have a timeframe when you would be able to review this? No rush, just need to ensure that I block out time to respond promptly during the review process.

Thank you for all of your help in the Otel community!

[cyriltovena]

Nice work @gramidt appreciate the effort 👏

We're starting a new repo for easing client integration here https://github.com/grafana/loki-client-go , I'm not saying you should use this, but just wanted to make you aware :) it would simplify your go.mod and how much vendor you have to pull into this repository.

How does the log push request batching is working ? Sorry to ask I'm not familiar with open-telemetry log collector.

[gramidt]

@cyriltovena - Thank you so much! I'm so glad to see that a Loki client was split out. This will definitely help with the inevitable dependency issue. I will go ahead and use the protos from 'loki-client-go' now, then submit a future PR with updating the code to use the other pieces of the client where applicable.

The OpenTelemetry Collector has the concept of Receivers, Processors, and Exporters. Receivers are responsible for getting data from systems (push or pull), Processors are responsible for processing the data (Batching, Queueing, Sampling, etc), and Exporters are responsible for sending the data off to a another system to either continue processing or storing the data. Here is the list of the "core" processors: https://github.com/open-telemetry/opentelemetry-collector/blob/main/processor/README.md . There are also additional "contrib" processors in this repo.

[gramidt]

@cyriltovena - After taking another look at the project, I will switch over to 'loki-client-go' for the protos after an official release of it is out. Looking forward to when it's available. :)

[gramidt]

Thank you for all of your help, @kbrockhoff!

[gramidt]

@bogdandrutu - When you're available, could you merge this?