feat(koa): Adds support to ignore a span by its layer name

[MrFabio]

Which problem is this PR solving?

• Adds ignoreLayersName option to instrumentation constructor config to allow layers to be ignored by its name.
• Currently we have the ignoreLayersType config, this new one will run after this check.
• It is useful if we want to ignore some layers like logger, allowedMethods, and some ones with no name. It also helps with reducing the number of spans.

Short description of the changes

• Defines KoaInstrumentationConfig with ignoreLayersName which is an array of string (layer names):
• Utils module with isLayerNameIgnored to check if a layer should be ignored by the name
• Modifies _patchLayer to check if the layer is ignored by the config

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: MrFabio / name: Fábio Gomes (30a395f)

[codecov]

Codecov Report

Attention: Patch coverage is 96.15385% with 1 line in your changes missing coverage. Please review.

Project coverage is 90.75%. Comparing base (5eb61d8) to head (30a395f).

Files with missing lines	Patch %	Lines
...lemetry-instrumentation-koa/src/instrumentation.ts	75.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2028   +/-   ##
=======================================
  Coverage   90.75%   90.75%           
=======================================
  Files         169      169           
  Lines        8018     8040   +22     
  Branches     1632     1638    +6     
=======================================
+ Hits         7277     7297   +20     
- Misses        741      743    +2     

Files with missing lines	Coverage Δ
...ode/opentelemetry-instrumentation-koa/src/types.ts	100.00% <ø> (ø)
...ode/opentelemetry-instrumentation-koa/src/utils.ts	100.00% <100.00%> (ø)
...lemetry-instrumentation-koa/src/instrumentation.ts	94.04% <75.00%> (-1.08%)	⬇️

... and 1 file with indirect coverage changes

[trentm]

@MrFabio What would you think about changing this from ignoreLayersName to ignoreLayers and copying the behaviour of the ignoreLayers config from instrumentation-express, given that instrumentation-express already has a very similar config option with (mostly) the same behaviour?

[trentm]

Is there a strong need to have a separate layerName from the name here? The name is the user-visible value used for the span name (IIUC), so it would be a little confusing to not match against that.

See also the matching handling that instrumentation-express does: supporting a string (exact match), regexp, or function for matching:

opentelemetry-js-contrib/plugins/node/opentelemetry-instrumentation-express/src/utils.ts

Lines 120 to 133 in 80d0c74

	const satisfiesPattern = (
	constant: string,
	pattern: IgnoreMatcher
	): boolean => {
	if (typeof pattern === 'string') {
	return pattern === constant;
	} else if (pattern instanceof RegExp) {
	return pattern.test(constant);
	} else if (typeof pattern === 'function') {
	return pattern(constant);
	} else {
	throw new TypeError('Pattern is in unsupported datatype');
	}
	};

[MrFabio]

That was because this logic ran after the name is mutated. This json is what I have when processing the metadata

{
    "attributes": {
        "koa.name": "/documents",
        "koa.type": "router",
        "http.route": "/documents"
    },
    "name": "router - /documents",
    "layerName": "/documents" <--- original layer name
}

so I used the layerName. I will change it to use the interpolated name instead.

[MrFabio]

Updated ✅

[trentm]

Given that instrumentation.ts calls isLayerIgnored in two different ways -- once to check the type and once to check the name -- I think it would be cleaner to have two separate isLayerTypeIgnored and isLayerNameIgnored (or whatever names).

For example, I think the current isLayerIgnored has an issue: when it is called without a name: isLayerIgnored(type, config), the code below that calls satisfiesPattern is still called, even though name is undefined. It shouldn't be called. Separating to two functions would make this cleaner.

[trentm]

Were these meant to have been adapted for isLayerNameIgnored()?