feature request: compatibility between published Go types to collector's own types

[errordeveloper]

Right now it's not easily possible to covert data that was constructed using published Go types (go.opentelemetry.io/proto/otlp) and the internal version of the same (go.opentelemetry.io/collector/model). This makes it very complicated for someone to build a collector component externally, e.g. they need to fork the collector repo or do other tricks, like marshalling and unmarshalling. Some types can be constructed using exported helpers, but it's hard to work with those and many fields are not settable.

[bogdandrutu]

This is intentionally, and encourage to construct use directly the go.opentelemetry.io/collector/model/pdata instead of go.opentelemetry.io/proto/otlp

[bogdandrutu]

Alternative you can "Marshal" the go "otlp" and unmarshal as "pdata"

[errordeveloper]

This is intentionally, and encourage to construct use directly the go.opentelemetry.io/collector/model/pdata instead of go.opentelemetry.io/proto/otlp

I found it very limited and unintuitive to use.

[errordeveloper]

Alternative you can "Marshal" the go "otlp" and unmarshal as "pdata"

Sure, if you don't care about performance...

[bogdandrutu]

" many fields are not settable." all the fields are settable, we are actually using them to construct everything.

[errordeveloper]

I've tried, and couldn't rewrite this code: https://github.com/cilium/hubble-otel/blob/acc3a282a62b35fa432b1d47200904082fbaf797/common/common.go#L178

It wasn't possible to handle AnyValue in the generic way with pdata. I don't remember exact details now, I'm afraid.

[errordeveloper]

@bogdandrutu this illustrates what I am actually referring to:

opentelemetry-collector/model/pdata/generated_trace.go

Lines 179 to 184 in db6d31e

	// NewResourceSpans creates a new empty ResourceSpans.
	//
	// This must be used only in testing code since no "Set" method available.
	func NewResourceSpans() ResourceSpans {
	return newResourceSpans(&otlptrace.ResourceSpans{})
	}

The thing is that Inside the collector you can set any fields you like cause internal structs can still be accessed, but not in another project... You see what I'm saying now?

[bogdandrutu]

@errordeveloper no I don't see what you are trying to say. If you need to create a new "ResourceSpans" you do from top to bottom:

td := pdata.NewTraces()
rs := td.ResourceSpans().AppendEmpty()

vs

rs := pdata.NewResourceSpans()
pdata.NewTraces().Append(rs) // or Set.

This is optimal to reduce the amount of allocations, as well as avoid common mistakes as "sharing" the same object between multiple data objects.

The thing is that Inside the collector you can set any fields you like cause internal structs can still be accessed, but not in another project...

Inside the collector we use "model" module and we don't have access to internal as any other project.