Support WithSpanNameFormatter to otelecho

[gifff]

Problem Statement

otelecho lacks support of custom span name formatter like one in otelhttp.

Proposed Solution

Add WithSpanNameFormatter option to otelecho.

Alternatives

Prior Art

opentelemetry-go-contrib/instrumentation/net/http/otelhttp/config.go

Lines 179 to 183 in 73c4165

	func WithSpanNameFormatter(f func(operation string, r *http.Request) string) Option {
	return optionFunc(func(c *config) {
	c.SpanNameFormatter = f
	})
	}

Additional Context

[pellared]

Why would we need to create a custom span name? I feel that the instrumentation library should follow the semantic conventions the semantic conventions: https://opentelemetry.io/docs/specs/semconv/http/http-spans/#name. The user can always create a child span with a custom name.

[dmathieu]

I would add: is this issue based on an actual need (could you describe it?), or is it just for parity with otelhttp?

[flc1125]

mark

[gifff]

Why would we need to create a custom span name? I feel that the instrumentation library should follow the semantic conventions the semantic conventions: https://opentelemetry.io/docs/specs/semconv/http/http-spans/#name. The user can always create a child span with a custom name.

I’m new to opentelemetry and currently learning to integrate it with existing system. So my initial plan was to annotate the span name with some prefixes so the span name becomes Echo/HTTP GET /some/actions for handlers and ServiceX/HTTP GET /some/other/actions for outgoing HTTP calls. I decided to use span.kind for filtering and add custom attribute to identify different http.Client(s).

Thanks for the pointer to the semantic conventions! I haven't gone through it.

[flc1125]

I decided to use span.kind for filtering and add custom attribute to identify different http.Client(s).

This is a very good choice. I am doing the same at the moment. And there are no problems at all.

[flc1125]

@pellared For this reason, we need to re-evaluate whether we need to add this feature.

#6375 (comment)