Minimum changes to component.Host, to allow split of the component package

[bogdandrutu]

This is the first step towards moving the [Receiver|Processor|Exporter|Extension] specific parts of the components package to its corresponding packages as defined in #6578. For that, we need to remove the component.Host dependency on component.Exporter and component.Extension.

Since component.[Exporter|Receiver|Processor] are useless interface given that we component.[Traces|Metrics|Log][Exporter|Receiver|Processor] exist, they can be simply removed.

component.Extension should not be removed, but GetExtensions() method of component.Host interface has to be changed to component.Host.GetExtensions() map[component.ID]component.Component to remove dependency on component.Extension. In this PR, it's done through aliasing, so it's not a breaking change. But, later, we will need to remove the aliasing, so make sure to update your implementations of component.Host.GetExtensions() from

component.Host.GetExtensions() map[component.ID]component.Extension

to

component.Host.GetExtensions() map[component.ID]component.Component

[codeboten]

Just one question, one way I could imagine doing this gracefully is by providing a new HostWithComponent interface and deprecating Host in favour of it, any thoughts?

[bogdandrutu]

@codeboten the idea behind this draft PR was mostly to agree on the path forward that it is possible to split component as I proposed initially, if we do this change (if we are ok with the result). We can debate how to get there, but important is the part that we have a path forward for the split of component, and I showed that in #6552

[codeboten]

@codeboten the idea behind this draft PR was mostly to agree on the path forward that it is possible to split component as I proposed initially, if we do this change (if we are ok with the result). We can debate how to get there, but important is the part that we have a path forward for the split of component, and I showed that in #6552

I'm ok with this plan, assuming others are as well. I think the changes to Host are minimal enough and help us untangle all the other components into more meaningful packages. I'm in favour of #6552

[codecov]

Codecov Report

Base: 90.94% // Head: 90.91% // Decreases project coverage by -0.03% ⚠️

Coverage data is based on head (fed87b8) compared to base (86d886c).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6553      +/-   ##
==========================================
- Coverage   90.94%   90.91%   -0.04%     
==========================================
  Files         241      241              
  Lines       14025    14077      +52     
==========================================
+ Hits        12755    12798      +43     
- Misses       1021     1027       +6     
- Partials      249      252       +3     

Impacted Files	Coverage Δ
component/exporter.go	96.07% <ø> (ø)
component/extension.go	86.66% <ø> (ø)
component/processor.go	96.07% <ø> (ø)
component/receiver.go	96.07% <ø> (ø)
component/componenttest/nop_host.go	100.00% <100.00%> (ø)
config/configauth/configauth.go	100.00% <100.00%> (ø)
exporter/exporterhelper/queued_retry.go	95.23% <100.00%> (ø)
receiver/scraperhelper/scrapercontroller.go	89.28% <100.00%> (ø)
service/extensions/extensions.go	82.97% <100.00%> (ø)
service/host.go	100.00% <100.00%> (ø)
... and 5 more

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[dmitryax]

Do we to remove component.Exporter and component.Extension only? What about component.Receiver and component.Processor?

[bogdandrutu]

Do we to remove component.Exporter and component.Extension only? What about component.Receiver and component.Processor?

Extension is the only one that needs to stay as a type.

[dmitryax]

Extension is the only one that needs to stay as a type

Can you please point me to why? I'm not sure splitting component package justifies removing only component.Exporter and leaving others as is

[bogdandrutu]

Can you please point me to why? I'm not sure splitting component package justifies removing only component.Exporter and leaving others as is

Not sure I understand, I said that only "Extension" needs to stay as a type since we don't have a TracesExtension, all the other will go, as you see in the PR.

[dmitryax]

Could you also please provide some reasoning behind this change in the PR description